Seattle Active Power GT40 - A Father/Son build
- Thread starter Peter Umino
- Start date
I can see the neighbor across the street getting a free GT40 when the winch brake breaks
and it's a Harbor Freight unit!! I usually put wheel chalks behind the car when I'm winching it up...just in case.
The scarier part was the first time I drove off the lift...triple checked that my brake pedal was firm! I even had my wife ensure our street was clear just in case.
a few miscl. updates...
Installed my Relay box from Painless...this will handle everything outside of the engine fuse box.
includes 8 relays, should be more than enough.
Making updates for the wire routing...the bottom holes are wires, the middle notches are for the cage door bar.
Turn signs work, including the hazards! always easier to test things outside the car....cause laying on my back under the dash is cramped!
Running the new rear wire harness for the tail lights...dropping zip ties, adding P-Clamps
Turn signals & High beam indicators
dash wiring...In hindsight I should have slowed down and completed all of the under-dash wiring when the dash was out. When I do paint this winter and remove all of the body, I'll likely re-wire the dash and make a few big bulkhead connectors so that it's more modular. Doing the wiring on my back really makes it hard to keep everything neat.
Installed my Relay box from Painless...this will handle everything outside of the engine fuse box.
includes 8 relays, should be more than enough.
Making updates for the wire routing...the bottom holes are wires, the middle notches are for the cage door bar.
Turn signs work, including the hazards! always easier to test things outside the car....cause laying on my back under the dash is cramped!
Running the new rear wire harness for the tail lights...dropping zip ties, adding P-Clamps
Turn signals & High beam indicators
dash wiring...In hindsight I should have slowed down and completed all of the under-dash wiring when the dash was out. When I do paint this winter and remove all of the body, I'll likely re-wire the dash and make a few big bulkhead connectors so that it's more modular. Doing the wiring on my back really makes it hard to keep everything neat.
a few more updates.
12VDC electric Heater: thought this would be simplier than a coolant version, it includes a small fan. I added 2 more in lines fans.
installed: put the heaters and 2 fans in the passenger footwell...I added a foot rest to ensure a passenger would never kick it.
Hood prop installed! I decided to go with a simple SS rod with a captive ball. works really well, and far better than the random ropes I had used from the ceiling.
Rear prop hood installed
door leathers installed to prevent them from being opened too far and contacting the hood.
The front had a ~5" ride height and ran out of threads to go any lower...so I got shorter spring and added the helper spring. Riding around 3.5" now, which is probably a hair too low for some of the speed bumps in my area. The set up works well, and lets me go lower than I'd want, and the helper spring ensures that at full droop, everything stays tight and the spring doesn't become unseated.
12VDC electric Heater: thought this would be simplier than a coolant version, it includes a small fan. I added 2 more in lines fans.
installed: put the heaters and 2 fans in the passenger footwell...I added a foot rest to ensure a passenger would never kick it.
Hood prop installed! I decided to go with a simple SS rod with a captive ball. works really well, and far better than the random ropes I had used from the ceiling.
Rear prop hood installed
door leathers installed to prevent them from being opened too far and contacting the hood.
The front had a ~5" ride height and ran out of threads to go any lower...so I got shorter spring and added the helper spring. Riding around 3.5" now, which is probably a hair too low for some of the speed bumps in my area. The set up works well, and lets me go lower than I'd want, and the helper spring ensures that at full droop, everything stays tight and the spring doesn't become unseated.
Hi you guys got some very nice GT cars, I just started a scratch car and was wondering were could I get the body parts? Thank you
Reach out to Chris at Active Power. Good luck! : http://www.activepowercars.com/
it's been a few months since I've updated here...I've been very fortunate with COVID to be able to work virtual, but that means my days are literally 100% in front of monitors, so I haven't felt like spending more of my off-work time making build updates; but I have spent a lot more time in the garage
Intake: This is a compromise set-up...but with all of my ITB issues, I just needed something "good enough" to get me through the next ~12 months, then I'll come back and figure out the permanent set-up.
I cutup the aft bulkhead surround to accomoate the intake piping coming into the cabin. Once I had installed the front windsheild, the air pressures were driving all of the engine bay fumes into the passenger compartment, so I needed something that would seal the bulkhead.
I then made a intake filter box, which mounts to the back of where the passenger seat would normally be.
This is the top of the intake box. Overall it turned out exactly what I wanted...
My little helper putting in all of the intake box bolts...small fingers are great!
The final intake installed. It's out of the way, keeps lots of room for groceries and tools in the passenger area, and sucks fresh air from the lower forward section of the engine bay.
I needed some cooler air coming into the passenger compartment, so I opened up the center NACA duct, and then added a seal on the footwell top panel and cut some holes.
The 1" raised compression seal does a descent job of sealing against the front hood. The lower 1/"4 seal is meant to keep any rain from entering the footwell.
The passenger area has a vent/fan that helps suck it in...but I added another set of holes above my feet. The NACA does a great job at pushing fresh air into this...but it needs ~40MPH or above to really provide cooling. The seals need a bit more work...as there's still some warmer air coming from the radiator that leaks in.
Intake: This is a compromise set-up...but with all of my ITB issues, I just needed something "good enough" to get me through the next ~12 months, then I'll come back and figure out the permanent set-up.
I cutup the aft bulkhead surround to accomoate the intake piping coming into the cabin. Once I had installed the front windsheild, the air pressures were driving all of the engine bay fumes into the passenger compartment, so I needed something that would seal the bulkhead.
I then made a intake filter box, which mounts to the back of where the passenger seat would normally be.
This is the top of the intake box. Overall it turned out exactly what I wanted...
My little helper putting in all of the intake box bolts...small fingers are great!
The final intake installed. It's out of the way, keeps lots of room for groceries and tools in the passenger area, and sucks fresh air from the lower forward section of the engine bay.
I needed some cooler air coming into the passenger compartment, so I opened up the center NACA duct, and then added a seal on the footwell top panel and cut some holes.
The 1" raised compression seal does a descent job of sealing against the front hood. The lower 1/"4 seal is meant to keep any rain from entering the footwell.
The passenger area has a vent/fan that helps suck it in...but I added another set of holes above my feet. The NACA does a great job at pushing fresh air into this...but it needs ~40MPH or above to really provide cooling. The seals need a bit more work...as there's still some warmer air coming from the radiator that leaks in.
Getting the front clamshell to sit flush...orginally I was thinking that I needed to shim up the windsheild base, but instead I installed a central Hood latch on the hood, and that holds the hood down flush. Far easier...and it keep the hood from bouncing up/down on the road when at speed.
Installed a Fire Extinguisher...still not sure if I like the position. But even once I have a passenger seat, it's far enough away that you wouldn't hit your head, and I do like that it's visible; just hope I never need it!
Installed the widnsheild...not cosmetically perfect, but descent, and it's water tight and strong.
Heating the edge of the windhseild to help the fiberglass sit flush.
I've been getting more and more miles on the GT40...one of the times I tried to pull the door closed from underneath the inner door panel and it immediately cracked. always frustrating, but it's also why I wanted to wait to paint it until I got some of these teething pains out of the way.
I added a simple pull strap mounted to the inside of the door latch. you need to be somewhat flexible to reach it, but it works well.
I mounted a central hood pin on the after clam. The center section is fairly thin, and the plexi rear doesn't add much structure...I didn't want aero loads pulling up the center section.
My passenger area is always filled with 2 sets of tools. I went to Harbor Freight and just bought a full 2nd set of cheap tools so that I could just leave these in the car all the time. I now have 1,000 miles on the car and I've yet to use it
Took the car out for a cruise around Seattle and to meet up with a good freind...he owns a DSP (Delivery Service Provider) for Amazon; I couldn't resist taking a pic next to 1 of his new vans.
Installed a Fire Extinguisher...still not sure if I like the position. But even once I have a passenger seat, it's far enough away that you wouldn't hit your head, and I do like that it's visible; just hope I never need it!
Installed the widnsheild...not cosmetically perfect, but descent, and it's water tight and strong.
Heating the edge of the windhseild to help the fiberglass sit flush.
I've been getting more and more miles on the GT40...one of the times I tried to pull the door closed from underneath the inner door panel and it immediately cracked. always frustrating, but it's also why I wanted to wait to paint it until I got some of these teething pains out of the way.
I added a simple pull strap mounted to the inside of the door latch. you need to be somewhat flexible to reach it, but it works well.
I mounted a central hood pin on the after clam. The center section is fairly thin, and the plexi rear doesn't add much structure...I didn't want aero loads pulling up the center section.
My passenger area is always filled with 2 sets of tools. I went to Harbor Freight and just bought a full 2nd set of cheap tools so that I could just leave these in the car all the time. I now have 1,000 miles on the car and I've yet to use it
Took the car out for a cruise around Seattle and to meet up with a good freind...he owns a DSP (Delivery Service Provider) for Amazon; I couldn't resist taking a pic next to 1 of his new vans.
Attachments
Some fairly big milestones...all thanks to COVID and having a lot more time at home!
Went to the local dyno to ensure the tune/engine were running well. Carb Conn in Kirkland WA is great, I've come here a few times over the years and they have already been great to work with.
Made just over 500HP at the rear wheels. This was the first pull....we weren't trying to make #'s, just making it safe and reliable. We gained something like 15HP peak, and ~30HP through a lot of the mid-range.
Getting ready for my Washington State Patrol Inspection....I had all their check-lists printed, completed, and all of the paperwork ready.
The Big day...took the day off work, and drove ~1hr north to the WSP inspection facility. With COVID-19, they were shut down for a few months, so all of the local places were booked solid. Was really looking forward to not spending $30 per 3-day permit every time I wanted to go for a quick test drive.
Waiting at the inspection facility...What should've been a 1 hr inspection ended up being nearly 2hrs! The WSP officer was really nice and easy to work with. He spent a lot of time documenting all of the major components (Engine, chassis, Transaxle,...), P/Ns, serials #'s,...both checking that I had receipts (aka they weren't stolen), and also to protect me in case the GT40 is ever stolen.
I was a bit worried that it was taking so long...I didn't mind waiting, but was worried I missed some peice of paperwork. Luckily at the end I got this!! The important detail is that it documented that the car was in the likeness of a 1968 Ford GT40...so that sets the stage for me to get Historic plates
I immediately drove to the local licensing office, and already had a 1968 vintage plate ready....so it's a 1 time registration for my "1968 Ford GT40"!
Went to the local dyno to ensure the tune/engine were running well. Carb Conn in Kirkland WA is great, I've come here a few times over the years and they have already been great to work with.
Made just over 500HP at the rear wheels. This was the first pull....we weren't trying to make #'s, just making it safe and reliable. We gained something like 15HP peak, and ~30HP through a lot of the mid-range.
Getting ready for my Washington State Patrol Inspection....I had all their check-lists printed, completed, and all of the paperwork ready.
The Big day...took the day off work, and drove ~1hr north to the WSP inspection facility. With COVID-19, they were shut down for a few months, so all of the local places were booked solid. Was really looking forward to not spending $30 per 3-day permit every time I wanted to go for a quick test drive.
Waiting at the inspection facility...What should've been a 1 hr inspection ended up being nearly 2hrs! The WSP officer was really nice and easy to work with. He spent a lot of time documenting all of the major components (Engine, chassis, Transaxle,...), P/Ns, serials #'s,...both checking that I had receipts (aka they weren't stolen), and also to protect me in case the GT40 is ever stolen.
I was a bit worried that it was taking so long...I didn't mind waiting, but was worried I missed some peice of paperwork. Luckily at the end I got this!! The important detail is that it documented that the car was in the likeness of a 1968 Ford GT40...so that sets the stage for me to get Historic plates
I immediately drove to the local licensing office, and already had a 1968 vintage plate ready....so it's a 1 time registration for my "1968 Ford GT40"!
I had signed up for the Packwood SCCA autoX National Tour event in early July, and was thinking I'd most likely run my M3, as the GT40 still had a descent amount of work needed before it was ready for an AutoX event. Luckily I was wrong...made it just in time; the only downside was that I had literally zero seat-time.
Muffler mods: SCCA has a sound limit, and when you car buddy who loves loud cars tells you that your car is REALLY LOUD...it's time to make some mods. I got these auger style inserts...at idle, there's not much difference, but it's a whole bunch quieter at full throttle; at some point I may take out a portion of these.
I also made some clamp on exhaust tips in case I was too loud and needed a quick fix. These will be useful in the coming years when I finnaly make the pilgrimage to Laguna Seca.
Muffler tips bolted on. Ugly, but effective. for SCCA, you can't point them to a specific side (ie. away from the microphone)...but Laguna Seca you can, so these simple slip ons will get pointed away from the noise booth.
Packwood WA is a good 2.5hrs from Seattle, so my friend and I opted to use his van and just tow the GT40 down...was also nice to have plenty of space for lots of tools! I drove the M3 down as well...just in case.
Like any good project...some last minute changes being done at the event. For those who haven't autoX'd at Packwood, this place is fabulous...lots of covered areas to park, and some of the best veiws of the Mt. Rainer area.
Not being too worried about actual performance, we signed up for the E-Modified class...I think we could've done X-Prepared, but didn't want to spend too much time reading the rules. for EM, the minimum weight was ~1,400 lbs...and we were 2,500; so a brand new car, never driven in anger, a track oreinted street tire, 1,000lbs over weight; You got that right, we had the biggest smiles of all!!
My co-driver Dennis pulling up to the line
and there he goes! The car was perfectly reliable, and the handling was within reason...no big issues, just lots of little adjustments that needs to be made (like tuning out the transitional oversteer). Did I mentioned how beautiful it is in Packwood?!
Action Shot curtesouy of the OR SCCA FB group.
Muffler mods: SCCA has a sound limit, and when you car buddy who loves loud cars tells you that your car is REALLY LOUD...it's time to make some mods. I got these auger style inserts...at idle, there's not much difference, but it's a whole bunch quieter at full throttle; at some point I may take out a portion of these.
I also made some clamp on exhaust tips in case I was too loud and needed a quick fix. These will be useful in the coming years when I finnaly make the pilgrimage to Laguna Seca.
Muffler tips bolted on. Ugly, but effective. for SCCA, you can't point them to a specific side (ie. away from the microphone)...but Laguna Seca you can, so these simple slip ons will get pointed away from the noise booth.
Packwood WA is a good 2.5hrs from Seattle, so my friend and I opted to use his van and just tow the GT40 down...was also nice to have plenty of space for lots of tools! I drove the M3 down as well...just in case.
Like any good project...some last minute changes being done at the event. For those who haven't autoX'd at Packwood, this place is fabulous...lots of covered areas to park, and some of the best veiws of the Mt. Rainer area.
Not being too worried about actual performance, we signed up for the E-Modified class...I think we could've done X-Prepared, but didn't want to spend too much time reading the rules. for EM, the minimum weight was ~1,400 lbs...and we were 2,500; so a brand new car, never driven in anger, a track oreinted street tire, 1,000lbs over weight; You got that right, we had the biggest smiles of all!!
My co-driver Dennis pulling up to the line
and there he goes! The car was perfectly reliable, and the handling was within reason...no big issues, just lots of little adjustments that needs to be made (like tuning out the transitional oversteer). Did I mentioned how beautiful it is in Packwood?!
Action Shot curtesouy of the OR SCCA FB group.
Neil
Supporter
Peter,
Congratulations on getting your car registered! That is a real Milestone.
"My passenger area is always filled with 2 sets of tools. I went to Harbor Freight and just bought a full 2nd set of cheap tools so that I could just leave these in the car all the time. I now have 1,000 miles on the car and I've yet to use it"
Anything in the cockpit should be tied down solidly. In a crash, all the loose stuff becomes ballistic and a box full of tools isn't something you want flying around.
Congratulations on getting your car registered! That is a real Milestone.
"My passenger area is always filled with 2 sets of tools. I went to Harbor Freight and just bought a full 2nd set of cheap tools so that I could just leave these in the car all the time. I now have 1,000 miles on the car and I've yet to use it
"Anything in the cockpit should be tied down solidly. In a crash, all the loose stuff becomes ballistic and a box full of tools isn't something you want flying around.
Peter,
Congratulations on getting your car registered! That is a real Milestone.
"My passenger area is always filled with 2 sets of tools. I went to Harbor Freight and just bought a full 2nd set of cheap tools so that I could just leave these in the car all the time. I now have 1,000 miles on the car and I've yet to use it
Anything in the cockpit should be tied down solidly. In a crash, all the loose stuff becomes ballistic and a box full of tools isn't something you want flying around.
Agreed. Early on when I was just putting around the neightborhood I had it loose, but once I got above ~20 MPH, I switched to a fabric tool bag, and use the passenger harness to secure it to the floor.
I keep dreaming of taking a month off work, and making the entire drive in the GT40 all the way to San Diego. Hit all the major tracks, and scenic roads along the way.
I've done a good amount of AutoX, mostly in the Seattle area, but also neighboring states and a few national events...Packwood is far from any major city which makes it harder, but it's also a really cool experience since it's beautiful scenery, and a really fun community; for the National Tour events, we likely double the population
100% agreed. I bought a ND Miata a few years ago down in LA, and drove it back along the coast w/ my wife all the way to Seattle. Would love to do many of those same roads to the music of a 427 rubmling behind me...although I doubt my wife would want to come on this trip, she likes a quiet smooth ride.
Last set up of updates...
Took the GT40 to it's 2nd AutoX...this time I made the ~100miles drive (1 way). The car drives well on the freeway, but the engine doesn't like being at ~2,000 rpms...it's some bad vibrations, which I assume is at part due to the big cam, and being hard mounted probably doesn't help. But I made it round trip w/ no issues, so the day was a big success!
2nd AutoX for the GT40. a Co-worker brought out his GT3 RS, and my friend borrowed my M3. This was a small practice session, so I pushed the limits a lot more...found some interesting dynamics...overseer in quick transitions (slalom, lane changes), and terminal understeer in steady state corners (big turn around sections). Overall times were descent and on-par with the GT3 RS...but I'd guess I'm still 1-2 seconds off the pace the car is capable of. But AutoX is not where this car will shine...I was lower RPMs in 2nd gear, and rarely full throttle; this is really about helping me tune the suspension, learn how the car handles at and beyond the limits,...and then get to a track day to stretch it's legs.
The rear Toyo R888Rs...with warmer temps (80-90F) and ~7 back to back autoX runs w/ only a few minutes between each run, these finnally heated up and actually started to get greasy. The outside edge had a lot more wear than inside...and when I checked camber afterwards, it made sense why; I had almost 0 camber! When I did the initial alingment it was when the car was lower...after I had some front tire rubbing issues at full lock, I raised everything...and never went back to check alignment.
AutoX Sucess...fun cars, great freinds, and chicken wings for dinner! The car behind us is the "Locost 7" that I build about 10 years ago which I sold to my freind Dennis (far right); it's far more suited for AutoX duty...~1,400lbs, 220HP (1.8L Miata turbo engine).
I plan to do paint this winter...and wanted to try out the color I've been thinking of; so I got a rattle can version and just did the radiator extractor portion. I'm terrible at body work...so this was also a good trial to help me improve, knowing that this will get sanded down later when it's done for real.
The paint I plan on using. It's Oslo Blue from Porsche...it's an older style paint that doesn't have flakes or anything fancy, but I like the color and it seems to match the vintage. I got a similar looking off-white that I was hoping would match.
paint is done, including a simple clear. No way near perfect, but I like the colors. Plan is to do the whole car in the Blue, then White for the radiator extractor and the big circular car #'s on the doors and front/rear hoods. There will be a few accents of Red,...the 2 tow hooks, and maybe 1 of 2 other pieces.
After the AutoX, I knew I had some rear alignment tweaks needed...I stopped at this point once I realized something was wrong. Toe was 1/4" out, and camber nearly 0! When I raised the rear, I knew it could tweak the static alignment, but didn't realize the ~1.5" rear ride height gain would've caused that much difference! I also spent extra time taking the rear inboard suspension apart and checking for any wear signs...so far, so good.
I made the rear sway bar w/ 4 holes each side for adjustment, and have adjustable end links...but I just had flat washers that only allowed for minimal angles, and therefore the end link could only use 2 of the mounting holes, not all 4. I had some left over high misalignment spacers from another project (left side of picture),...I didn't need the full thickness, so I made my own smaller versions (right side); I was going to do them on my small lathe, but I was using an existing spacer that didn't have much length, so I just files them down on my sander (I let them rotate as I sanded, which worked out perfectly).
Took the GT40 to it's 2nd AutoX...this time I made the ~100miles drive (1 way). The car drives well on the freeway, but the engine doesn't like being at ~2,000 rpms...it's some bad vibrations, which I assume is at part due to the big cam, and being hard mounted probably doesn't help. But I made it round trip w/ no issues, so the day was a big success!
2nd AutoX for the GT40. a Co-worker brought out his GT3 RS, and my friend borrowed my M3. This was a small practice session, so I pushed the limits a lot more...found some interesting dynamics...overseer in quick transitions (slalom, lane changes), and terminal understeer in steady state corners (big turn around sections). Overall times were descent and on-par with the GT3 RS...but I'd guess I'm still 1-2 seconds off the pace the car is capable of. But AutoX is not where this car will shine...I was lower RPMs in 2nd gear, and rarely full throttle; this is really about helping me tune the suspension, learn how the car handles at and beyond the limits,...and then get to a track day to stretch it's legs.
The rear Toyo R888Rs...with warmer temps (80-90F) and ~7 back to back autoX runs w/ only a few minutes between each run, these finnally heated up and actually started to get greasy. The outside edge had a lot more wear than inside...and when I checked camber afterwards, it made sense why; I had almost 0 camber! When I did the initial alingment it was when the car was lower...after I had some front tire rubbing issues at full lock, I raised everything...and never went back to check alignment.
AutoX Sucess...fun cars, great freinds, and chicken wings for dinner! The car behind us is the "Locost 7" that I build about 10 years ago which I sold to my freind Dennis (far right); it's far more suited for AutoX duty...~1,400lbs, 220HP (1.8L Miata turbo engine).
I plan to do paint this winter...and wanted to try out the color I've been thinking of; so I got a rattle can version and just did the radiator extractor portion. I'm terrible at body work...so this was also a good trial to help me improve, knowing that this will get sanded down later when it's done for real.
The paint I plan on using. It's Oslo Blue from Porsche...it's an older style paint that doesn't have flakes or anything fancy, but I like the color and it seems to match the vintage. I got a similar looking off-white that I was hoping would match.
paint is done, including a simple clear. No way near perfect, but I like the colors. Plan is to do the whole car in the Blue, then White for the radiator extractor and the big circular car #'s on the doors and front/rear hoods. There will be a few accents of Red,...the 2 tow hooks, and maybe 1 of 2 other pieces.
After the AutoX, I knew I had some rear alignment tweaks needed...I stopped at this point once I realized something was wrong. Toe was 1/4" out, and camber nearly 0! When I raised the rear, I knew it could tweak the static alignment, but didn't realize the ~1.5" rear ride height gain would've caused that much difference! I also spent extra time taking the rear inboard suspension apart and checking for any wear signs...so far, so good.
I made the rear sway bar w/ 4 holes each side for adjustment, and have adjustable end links...but I just had flat washers that only allowed for minimal angles, and therefore the end link could only use 2 of the mounting holes, not all 4. I had some left over high misalignment spacers from another project (left side of picture),...I didn't need the full thickness, so I made my own smaller versions (right side); I was going to do them on my small lathe, but I was using an existing spacer that didn't have much length, so I just files them down on my sander (I let them rotate as I sanded, which worked out perfectly).
Peter,
First let me start by saying your build is one of my favorites I've seen... primarily because I relate to its direction the most. I did not know of Active Power until reading your post and am very excited about the chassis / body. I emailed them about 30 minutes ago with some questions but I had some for you as well if you don't mind!
First let me introduce myself. My name is Nick and I am a recent grad from Clemson University's Mechanical Engineering program. I am doing automotive engineering in Columbus Ohio where I grew up. I have worked on old muscle cars restoring them and maintaining them since I was 13. (Now 24). It has been a dream of mine for years to build my own GT40 that can tear up the track. I have many coworkers that head to mid ohio on the weekends.
Now for the questions...
1. I read on Active Power's website that they support a Windsor and Coyote engine. I definitely want to run an LS as it is cheap, reliable, and simple. I am excited to see that you made an LS work on the chassis. Could you share some insight into how you made that happen? Where did you get an adapter plate? You chose a beautiful engine but I am probably picking out an ls from a local junkyard. How high can you comfortably rev up the LS3? Are the heads stock? I am willing the spend some extra money on the valvetrain if it means I get some extra revs. Hoping you could provide some insight here. Do you plan to isolate the drivetrain at some point to mitigate the harsh vibrations at 2000rpm you mentioned?
2. Your pushrod suspension really caught my eye... would you be kind enough to share some details on it? Like the hardware you chose? (pushrod/shock)
3. Currently I am settled on using a Porsche 996 transaxle (G96/01). With your extra horsepower you rightfully so went for something better. However I am curious about whether or not you are running a LSD. Also wondering what axles you chose/would recommend.
4. I really like your roll cage. Could you share some more details on it? Was part of it an extra when buying from Active Powers and then you just welded in the door bar?
5. People have crafted very different fuel systems on their builds... would you please give some more details on how you built yours? I read that you have one tank supplying the other and a single main feed. How has this worked so far? Did you also run a swirl pot? What is some of the hardware you used?
6. I read that you used a baffled oil pan. Many of my coworkers strongly suggest a dry sump setup over baffled pans. They are saying an oil system is one thing not to cheap out on for a track day car (especially for an LS). Have you head any problems with starvation? A dry sump system is expensive so wondering if you could convince me that it ISN'T worth it.
7. Are your sway arms custom or where did you get them?
I apologize for the huge amount of questions I hope I am not asking too much. I am just trying to do my "homework" so to speak before I pull the trigger...
Thanks in advance!
Nick
First let me start by saying your build is one of my favorites I've seen... primarily because I relate to its direction the most. I did not know of Active Power until reading your post and am very excited about the chassis / body. I emailed them about 30 minutes ago with some questions but I had some for you as well if you don't mind!
First let me introduce myself. My name is Nick and I am a recent grad from Clemson University's Mechanical Engineering program. I am doing automotive engineering in Columbus Ohio where I grew up. I have worked on old muscle cars restoring them and maintaining them since I was 13. (Now 24). It has been a dream of mine for years to build my own GT40 that can tear up the track. I have many coworkers that head to mid ohio on the weekends.
Now for the questions...
1. I read on Active Power's website that they support a Windsor and Coyote engine. I definitely want to run an LS as it is cheap, reliable, and simple. I am excited to see that you made an LS work on the chassis. Could you share some insight into how you made that happen? Where did you get an adapter plate? You chose a beautiful engine but I am probably picking out an ls from a local junkyard. How high can you comfortably rev up the LS3? Are the heads stock? I am willing the spend some extra money on the valvetrain if it means I get some extra revs. Hoping you could provide some insight here. Do you plan to isolate the drivetrain at some point to mitigate the harsh vibrations at 2000rpm you mentioned?
2. Your pushrod suspension really caught my eye... would you be kind enough to share some details on it? Like the hardware you chose? (pushrod/shock)
3. Currently I am settled on using a Porsche 996 transaxle (G96/01). With your extra horsepower you rightfully so went for something better. However I am curious about whether or not you are running a LSD. Also wondering what axles you chose/would recommend.
4. I really like your roll cage. Could you share some more details on it? Was part of it an extra when buying from Active Powers and then you just welded in the door bar?
5. People have crafted very different fuel systems on their builds... would you please give some more details on how you built yours? I read that you have one tank supplying the other and a single main feed. How has this worked so far? Did you also run a swirl pot? What is some of the hardware you used?
6. I read that you used a baffled oil pan. Many of my coworkers strongly suggest a dry sump setup over baffled pans. They are saying an oil system is one thing not to cheap out on for a track day car (especially for an LS). Have you head any problems with starvation? A dry sump system is expensive so wondering if you could convince me that it ISN'T worth it.
7. Are your sway arms custom or where did you get them?
I apologize for the huge amount of questions I hope I am not asking too much. I am just trying to do my "homework" so to speak before I pull the trigger...
Thanks in advance!
Nick
Great to hear, thanks! You'll like Chris (Owner of Active Power)...very much a fellow car enthusiast!
-Chris has a dummy LS block, so I just told him the transaxle and he did the engine & transaxle mounts. Key to remember is that everything is super tight clearances...so it took me some time to find the right accessories/mounting, as they needed to hang low (Alt, water pump)
-The LS3 is hard to beat...OE drivetrain is ~6,600rpms. I didn't mess w/ that...especially w/ so much low end power, I haven't considered the need to have it rev higher.
-The main concern I hear about LS3 motors is oil starvation at sustained high lateral G's (Long sweepers on the track w/ R-Comp tires)...so I got an accusump system, I just haven't installed it yet.
-Harsh vibrations: I don't plan to do anything about it....my engine/tranny is hard mounted to the chassis (Delrin bushings), so I was expected some harshness.
I'll have to go dig up my notes, and likely just measure it. I'd do it again, but would likely make a few small changes.
The Mendeola transaxle includes a clutch style LSD. On a previous Porsche 911 I had an open diff, and at higher power levels it would spin the inside wheel...so I was certain I wanted an LSD on the GT40
Chris put in most of the cage (it's one of his options)...the longitudinal door bar integrates with the fuel tank structure, so it's essentially a standard dual side bar design (very strong against side impacts). It's very tight clearances inside, and Chris did a great job maximizing space. I added vertical pinned door bars, which help to triangulate the front hoop...
Currently I only have 1 fuel tank installed. I bought ATL fuel cells w/ integrated baffles into the back of the fuel tank, so it acts like a swirl pot to help prevent fuel starvation. I'm using a Bosch 044 fuel pump...old tech, but well know and rated for my power levels.
-2nd tank: This will be a very simple set-up that only has a pump to transfer fuel to the primary tank. so I'll have to manually turn on the 2nd fuel pump to transfer...and then turn off; my main concern is that I'll forget to turn it off, so I'll add an overflow line between the 2 tanks.
-I haven't had any issues thus far, but I am concerned about overheating the fuel when driving stop/go, as the fuel pump is constant speed...if that occurs, I'll either use a PWM fuel controller to slow down or speed up based on RPM, or just buy a newer (and $$) brush-less pump setup. In hindsight I should've done this up front...but it's easy to get "analysis paralysis" in all of the details, so I was conscious to make decisions and just get the car running...then I'll have years to perfect.
I agree (see my above comment about the accusump)...we were quickly hitting our budget limit, so the oil baffle and accusump was our compromise. The other factor is that I'm not sure if I'll ever run full slicks on it...I plan to drive it to most events, so it'll need street-able tires.
Yes, got them from Speedway Engineering. Really nice quality. The arms come straight...then the fronts I cut/bent/welded to clear the front suspension. I liked the speedway set-up as I could order different thicknesses...currently I have 3 bars, and with the arms having multiple holes, there's lots of adjust-ability. (http://1speedway.com/index.php?route=product/product&path=81&product_id=113)
Hope that answers most of your questions. If you're ever in the Seattle area, make sure to stop by!
