Ok guys help me.

[Erik]

I am still in the research part of building a SL-C. So please for forgive me asking. I am debating Between three main motors. One is the new Ford 5.0 414 claimed hp. I heard more then once ford underrated it. Its more like 430. A LS3 with a hot cam 480hp. The ls7 with 500 hp.

I have a few things that scare me about the Ls3 and 5.0. The main thing is there wet sump. I don't plan on this being a road only car. I live a few hours from Brainerd International Raceway and Road America. Those two tracks have very high speed turns. I am worried about oil not getting to the motor. Plus I plan on doing autocross a lot.

I know the ls3 can be converted to dry sump. But that will not be cheap. Its almost 2-4 grand more. I also know That the ls3 has a few good pans out there for auto racing. The ford is to new for munch of any thing right now. Give it a year or two parts will be coming. I have never heard of a Ford engine smaller the 5.4 being dry sump.

My main goal is at least 550 hp total. I know the ls7 with good plugs and wires, a intake and throttle body, and a good tune could touch that. That is from what I have seen on Chevy forums.

I also know that if I buy the ls3 I will need to spend a few more bucks to hit that same hp number. I am thinking at lest a tune, intake, plugs, wires, some minor valve train work, and maybe a mild port job. But that should still be cheaper then buying a ls7 by a long shot. Most of it me and a buddy could do in mine or his shop. I am just worried about getting it to a dyno. I am guessing I would have to take it to a dyno to get it tuned right with that munch work.

Like I said the 5.0 is to new yet. But when I saw one in a SL-C I started looking. The motor is about the same price of the ls3. I saw that ford is making a supercharger for it. That will give me 620 some hp. It comes with every thing even a tuner. Just spend a day putting it on. Run the program into the computer and you set to go. But that a total investment of over 12 grand. I am not sure if I would want that munch hp on a car the top out at 2400 lbs. Not to many cars scare me, but that would.

I have read on this forum were a guy with a SL-C wished he would have bought a Ls3 instead of the Ls7. I think I read that it would have been cheaper to tune a ls3 then the buying the ls7 in total. Maybe if he reads it he can tell me why.

Sorry about the long post. I am sure this wont be my last. I just like to do my research before I buy.

 

[Doc Kaler]

Hi Erik,

It appears that you have done some planning for a "dual purpose" SLC. When you get into purpose-built racing tires and higher G cornering you probably would start to want the dry sump setup. You would also want to consider a higher pressure internal oil pump at the least. Depending on your anticipated RPM limit, at least a rocker arm trunnion upgrade or even beam-type rockers may be needed. The LS7 dry sump setup is effective when running high performance street tires but may not be adequate with R compound tires, so an upgraded setup may be in order. You can use an Accusump with either a dry sump or wet sump setup. If you "start" with a hot-cam LS3, I'm not certain you can get to 550+ HP with the mods you mentioned but someone can correct me if I'm off base. I have an LS7 with a few mods for the track and I am pleased with my choice. I know Fran uses the LS3 in the factory race SLC with fantastic results, but I'm not sure what has been done internally.

 

[Fran Hall RCR]

The FoMoCo SC package for the Coyote will not fit insde the stock SL-C bodywork...we have tried.
Doc is correct...
The LS7 is rated at 505 hp but in reality they are much closer to 535-540hp straight from the box..
My race SL-C has an LS3 based engine and it takes far more than cam, port job to make 590hp(crank)...a nice tune on the dyno for a stock LS7 will get you where you want to be...and its dry sumped to boot....just make sure to use a 3 gallon tank minimum...the mods that Doc mentiones should be done to any serious LS series engine...most are not expensive but are good for long term reliabilty.
It will cost you more to build the LS3 to the power levels of the LS7, even at full retail for an LS7.

Next years race car will be running an LS7 based engine...so we can keep up with the 700hp SU guys ...oh wait...we already beat them with under 600hp...:stunned:

 

[Alex]

Right or wrong here's my take - I'd put a 1000hp carb'd LS in it and call it a day

Unless you're tracking it, don't worry about power-to-weight .... it's easy to drive if you arn't retarded and feel the need to stab the gas pedal at every light. Tracking it...I dunno, go to the standing mile, heh.

I'd personally rather have a professional built-up LS3 than a mild stocker LS7 - you'll get the engine the way you want it, make more power, and be more reliable. I've seen a lot of threads on sites like ls1tech where people basically treat a crate LS7 as a ticking timebomb, expecting to have to heads-off work to it at some point in the future(?something like weak valves, I dunno, I'm not an expert on it, somebody else can probably add more details?).

I'd also expect to put any engine I purchase on the dyno - you're paying $10k+ for an object you don't want to explode on you ... I'd darn sure pay $500 to make certain the a/f is bang on and everything is a-okay.

But again, that's just my non-professional opinion.

 

[Erik]

Ok Fran my real name is Erik. I think I might have screwed up the display name and screen name. If you want as a mod you can fix it. I am not sure how to fix it if I can.

Fran I didn't know Chevy underrated there motors. I guess the 550 hp goal is more easier then what I thought. Like you said a good tune should get me them numbers.

Doc you have any good links to parts and what not. I have a few saved. I might go with the ls7 like you and Fran said. I wish I would have saved the one for converting r compound tire numbers to street tire numbers. I will have to Google it. The car will see 1-20 track days a year. I know the Porsche club gos to road America a few times a year. I would love to smoke some of them. If I smoke a gt3 rs my dream Porsche I will be very happy.

I also have to head over to the shop Fran. Its just a 10 hour drive one way. I would feel like I am wasting your and my time if I didn't bring you a 20k check. I might see if one of my buddy's are going to any red wings games this year. I then could tag along and take a shop tour.

I also had a good dream a few nights ago. I had a white SL-C in my shop running at idle. All my buddy's were sitting there with there jaws on the floor. There wife's and girlfriends were all pissed that a car was getting more attention then them. They were also saying that I was overcompensating for some thing. After that dream I really need to get one now.

 

[Doc Kaler]

Erik,

I have a ton of links I can send to you if you go the LS7 route. Roberto (Stage7) is very experienced with the LS platform and may have suggestions as well. There are a few potential weak spots in the LS7, some of which I addressed. Given the number of track days you may want to up the build. First, changing to the LS9 internal oil pump or the Katech version, possibly changing out the timing chain to the C5R version, using a 3-gallon oil tank as Fran mentioned, changing out the valve train (I think both Roberto and I use Jesel roller rockers) will add to the longevity of the build. You can go with the ARE dry sump and Aviad external scavange pump. Most of this will do no significant increase in HP......that's another list. I've heard of the trunnions in the stock rockers letting needles go free, of the stock dry sump pan allowing some sloshing away from the pickup with R-compound tires, of the stock internal pump not maintaining adequate pressure on the track, of the stock vette oil tank being too small. But no mention of valves letting go. That may be related to the builder/cam lift/valve springs/rocker geometry selected. I'll PM some links if you like.

 

[Alex]

But no mention of valves letting go. That may be related to the builder/cam lift/valve springs/rocker geometry selected. I'll PM some links if you like.

Now I vaguely remember - valve drop on LS7s
e.g.,
Ls7 valve issues--real or E-phenom? - Corvette Forum


There have been dozens of threads about this issue on ls1tech and cf

 

[Erik]

Alex I feel like I have to tell you this. I have never touched a car carb in my life. I am only 26. So every car I have owned never had one. So the carb idea is out. Nothing wrong with them. I just come form the EFI world.

I wish I dyno would only cost 500 dollars. That sad part is it wont. Its going to cost more like 2 grand. I would have to drive 5 hours to chicago or the twin city's for a good dyno shop. I would most likely also have to take a day off from work. Then add one at lest a half a day on the dyno. If I am driving that far. I would want to get good use of it. I just asked if I need a dyno. I figured if I went with more then basic bolt ons I would need it.

I have also thought about building a motor my self. I have no doubt I could do it my self. I might need some help form a buddy but that's about it. I am just not sure yet if I would like to build my own.

I also have heard about the valve train problems. Alex thanks for the link. I will read it after I post. If me and a buddy have to spend a day prepping the valve train so be it. Its cheap insurance. Also if I have to tare part the bottom end like doc said for up grades. I am not afraid one bit.

Doc thanks for helping me. You can send me the links.

 

[Doc Kaler]

Will do Erik. The thread is interesting and reinforces the fact that if you want to track your car regularly be prepared to inspect/rebuild, use premium parts (in the LS7, that means special attention to the oiling and valve train), stay within the parameters of your engine design. This is not exclusive to the LS7, BTW (personal experiences!). That said, if you want a "dual purpose" car, consider staying on premium performance tires with moderate attention to the oiling.

 

[Alex]

Alex I feel like I have to tell you this. I have never touched a car carb in my life. I am only 26. So every car I have owned never had one. So the carb idea is out. Nothing wrong with them. I just come form the EFI world.

I wish I dyno would only cost 500 dollars. That sad part is it wont. Its going to cost more like 2 grand. I would have to drive 5 hours to chicago or the twin city's for a good dyno shop. I would most likely also have to take a day off from work. Then add one at lest a half a day on the dyno. If I am driving that far. I would want to get good use of it. I just asked if I need a dyno. I figured if I went with more then basic bolt ons I would need it.

I have also thought about building a motor my self. I have no doubt I could do it my self. I might need some help form a buddy but that's about it. I am just not sure yet if I would like to build my own.

I also have heard about the valve train problems. Alex thanks for the link. I will read it after I post. If me and a buddy have to spend a day prepping the valve train so be it. Its cheap insurance. Also if I have to tare part the bottom end like doc said for up grades. I am not afraid one bit.

Doc thanks for helping me. You can send me the links.

Even better idea to use a carb - easier to tune, haha I think it's a lot easier than tuning fuel injection myself - I hadn't seen a carb until I was 25 and built my 65 cobra ... adjust the float screws, adjust the idle screws, plug in your wide-band for fine tweaking, then deal w/ the jetting.

 

[Tom]

Erik,

if you talk with Thomson automotive in Michigan you might be surprised at the cost for a built LS7. Doc mentioned some of the potential weak spots in the motor, using aftermarket exhaust valves and a rocker rebuild from Comp Cams results in a reliable valve train for not too much $.

Best of luck on your project.

Tom

 

[Fran Hall RCR]

Tom,

Thompson are good friends of mine and they are actually my engine builders for 2012.
I have used dozens of their builds over the years...never had a problem.
Just like Katech, you get what you pay for.

 

[Erik]

I found Tomson's web site. I think I found my motor. I just cant figure out of I need to provide a block or not. They say they don't need a core exchange.

Here is what I got from there web site. If I did all that my self. There would be no way I could touch that for 14k. It sounds like its almost a bullet proof motor the way they build them.

Tire-Killing Capability with 550-650+ Horsepower!
The LS7 engine is a legend in its own time. With more than 500 horsepower from the factory, it delivers power that was reserved for race cars only a few years ago.
But as powerful as the LS7 is, we couldn't help but explore its capabilities. The result is Thomson Automotive's range of Ultimate LS7 performance engines. We start with a LS7 7.0-liter (427-cu-in) core and perform the following upgrades:

• Bore and hone the cylinders with torque plates
• Rebalance the rotating assembly
• Replace the factory cast pistons with stronger forged aluminum pistons
• Install custom, file-fit piston rings
• Install one of our custom-grind camshafts
• Add stronger valve springs and retainers to withstand the lift of the new cam
• Available in dry-sump or wet-sump configurations

Our most basic upgrade delivers about 550 horsepower, while our most radical cam enables 650 horsepower or more!
We also offer a number of component upgrades to suit your needs, as well as a variety of oil pan applications to fit your vehicle.
When it comes to engine assembly, Thomson's experienced engine builders meticulously measure and re-check tolerances and clearances to ensure the engines make big power reliably.
Ultimate LS7 engines start at $14,995. (No core exchange required.)
Thomson Automotive is a leader in high-performance LS engines. We've spent countless hours designing, building and dyno-testing street and strip engines, from production-based, normally aspirated engines to custom, forced-induction and nitrous engines. We know what works.
Give us a call and let us build an Ultimate LS7 performance engine for you!

 

[Ken Roberts]

Here is my choice for a strong low cost LS engine going in my planned SLC next year.

Dry sleeved LSA block (has piston oil squirters from the factory). This block is similar to the LS3 but was used in the super charged CTS-V. The cast sleeves are replaced with ductile iron sleeves (much stronger) and are longer than the factory sleeve. Displacement now becomes 427. Long nose forged crank to be used with a Katech LS7 machined oil pump. Katech C5R timing chain (a must). Dry sump factory LS7 oil pan modified with internal baffles to control oil slosh. ZR1 factory fluid to fluid oil cooler (just to be different). West Coast Cylinder Head machined LS3 heads. 3 Gallon dry sump tank. Pat G spec'd cam for around 570hp (flywheel HP).

The short block sells for about $7000 outright from ERL. The cylinder heads are about $2100 from WCCH.

 

[Doc Kaler]

Ken,

I have the C5R chain and did not see any improvement over the LS7 chain. The C5R chain is not seamless. The LS7 chain was seamless. Given that, we decided to box up the C5R chain, so I now have it as my back-up. I understand the need to have a strong chain, but compare the two chains next to each other. I was kind of surprised. Maybe I have a better chain already installed?

 

[Erik]

I talked to a buddy about this same topic. More or less about building a bullet proof drive train. He agrees with me about going through Thompson. We both know I couldn't even touch 15k with me building it my self. So thinks spud and fran for the info on them.

We also talked about me buying a used pro 4 corr tuck engine. That would be a blast. 700 plus hp and with a carb like Alex would like. The only problem is that no one is selling one yet. There also might be a problem if some thing breaks. The good thing is he works for corr teams. So parts might not be hard to find. They just wont be cheap.

 

[Alex]

Did somebody just mention a carb ........

I have no idea what a pro 4 corr engine is, but if that's the way you wanted to go you can easily knock that out with an LS......at least there parts are available and cheap.

 

[Erik]

Alex thanks for the laugh. Corr trucks are what type of truck you see at baja. Corr folded a few years ago. It became the Traxxas torc Series. Most people still call them corr trucks. But they go buy many names manly corr trucks, Throphy trucks, soda trucks. They usally have engine specs like NASCAR dose. I think there max engine displacement. I will have to get back to you on that. But NASCAR limits it to 358 c.i.

Alex here is a pro 4 torc race.
http://www.youtube.com/watch?v=08tlYt52N5E