turbochargers?

John · 02-11-04, 06:42 PM

Hi everyone,

I'm a new guy and have a possibly flameworthy question.

I don't yet have a GT40 (hopefully will buy a kit within a few years), but love any sort of fast car. So, when I do eventually build a kit, I'd like it to be able to get up and go!

Now, I realize that I'd be just fine (and better off financially) with a fairly mild small block Ford... but just for the sake of conversation has anyone ever built a twin-turbo V8 for their GT40 kit?

It seems like there wouldn't be much room back there for the turbo plumbing (especially with intercoolers) and that the heat from the turbos might cause problems. But turbos are just so fun! (I have a twin turbo car... it is great)

So, while I probably couldn't afford to do it, and wouldn't anyway because it would be a headache and much more power than I need... what about a 32 valve Ford 302 (heads at www.araoengineering.com ) with twin turbos? I've seen small block V8s with twin turbos running close to 2000 horsepower... could any transaxle survive that?

Anyway, just a thought. Nice meeting you all. Flame away! [img]/ubbthreads/images/graemlins/smile.gif[/img]

John
www.geocities.com/boodlefoof

Bill Bayard · 02-11-04, 07:27 PM

Hi John,

Welcome to the Forum!

Before the flame wars begin, do a search on the 32 valve heads, turboed 40s, and bulletproof gearboxes. These topics have been discussed at length in the past. You'll find some good information to add to your research file.
The "cool factor" of a high horsepower(over 500HP) GT40 doesn't add up to the high cost factor, unless you plan to use the car exclusively on a track, or have an unlimited supply of cash!
GT40s are light cars, and don't require that much horsepower
to have plenty of get up and go. I had a 514HP 392W in my car, and replaced it with a more streetable 425HP 351W, as the rear tires and clutch were taking a pretty hard beating!
Before you decide on a 2000HP, fire breathing monster, catch
a ride in a GT40 of 450HP or so. Unless you are some kind of speed psycho, that should be plenty.

Bill

Bill Musarra · 02-11-04, 09:21 PM

Bill,
I never knew you were so tame!! [img]/ubbthreads/images/graemlins/grin.gif[/img]
Bill

Brian Kissel · 02-12-04, 01:49 AM

Welcome !!
If you are going to wait for the ARAO heads, it certainly will be a few years down the road on your build. It took me 9 months to get any kind of response from them after countless emails, snail mails, and even leaving messages on their answering machine. I last heard from them back in September I believe. Their latest promise was a full information packet, and a updated website. If you look at their website,I would bet it still says 2002 on it. Use the search feature, and there is more information on them. Whatever you do, don't send them ANY money up front. When and if the heads are ever available but them COD.

Regards Brian

Danny · 02-12-04, 05:45 AM

Hi John,

If you do a search I know there are some posts of a twin turbo GT40 around hear somewhere. IMO there is plenty of space for a turbo system though as you say heat could be an issue especially with the fibre-glass rear clip. There are guys more knowageable about 40's around here than I so I'll leave it at that. There are a few non-gt40 TT V8's around one in particular is here: The judge

Unfortunatly the guy who engineered these cars died in a motor racing accindent though some of the specs are still up on the site if you are interested. May give you an idea on whats required.

As far as Fords I have also read an articles on a TT Pantera (think they had 351 clevos in them?) and an Aussie XC Falcon Cobra (Performance Ford mag) 351 with Twin To3 turbos. Engine dynoed 370kw (496 hp) at a mild 10lbs. You have to admit that would be extreme in a car as light as a gt40. But a hell of a lot of fun!!!!

Cheers,

Danny

Bill Bayard · 02-12-04, 06:41 AM

Bill,

I'm not![img]/ubbthreads/images/graemlins/crazy.gif[/img] Just more cautious! The more close calls I

have, the crazier I was! [img]/ubbthreads/images/graemlins/grin.gif[/img]

Bill

John · 02-12-04, 09:46 AM

I took a quick peek at some old threads using the search term "turbo" but most all of them seemed to be talking about a specific transaxle from a porshe. I'll look again to see if I can find any turbocharger info.

I realize that a 2000 horsepower monster would be comlete overkill. [img]/ubbthreads/images/graemlins/cool.gif[/img] I don't plan on doing it, (although I really love the feeling when the turbos spool up) but it is good to hear some info about those Arao heads. I was seriously considering those at some distant time in the future.

I'll check around the archives some more to find some info on the heads. Thanks!

P.S., for those of you wondering... yes, I'm a youngin! Just 22 yet. [img]/ubbthreads/images/graemlins/grin.gif[/img]

Kevin M · 02-12-04, 10:53 AM

John,

Three thoughts on how far there is any point going with the engine in one of these:

Traction, Traction, Traction.

You can unquestionably make more power than you could ever hook up, even with full racing tires on the car. (You never mentioned if you plan the car primarily for street use or track use). The transaxle issue is not as bad as it might seem because the rear tires will break loose and spin before you can put too much load on the drivetrain. The minimum point of entry would be something like an RBT ZF and then from there, there are Hewland and Ricardo racing boxes if you are planning a track car.

Bill Bayard’s comments were very revealing. (Bill correct me if I’m wrong, but I believe you are using 255/16 rear tires?). For a high HP car you will want Gulf Flairs and the largest rear tires you can get (335/17 or 345/18). DOT race rubber would be a good idea if you don’t plan to drive the car when it rains.

It would be very interesting to hear from some of the other members with fairly high HP engines (450 HP and over) what rear tires they use and what their experiences have been with the minimum speed at which they can get the car to hook up. If you can’t get the throttle all the way down below 80 MPH, is there anything to be gained from more power? (Assuming we are not talking a track only car).

Hopefully some of the other members will be willing to share their experiences here and give you some idea where traction can no longer be had and more engine is pointless.

Kevin

Bill Bayard · 02-12-04, 11:37 AM

Kevin,

225/50ZR16s & 255/50ZR16s. With the 500HP+ engine, traction was a BIG issue, even with a Quaife LSD. I could break the rear tires loose at 90MPH+, when shifting from 3rd to 4th.
I also blew the springs out of a clutch disc. With wider rear tires, the odds of damaging drivetrain components become greater, hence the 255s. I went back to my old engine(425HP), as it was only a matter of time before I did some serious damage, both to myself and the car. It will still smoke the tires, but is FAR more comfortable to drive under everyday conditions. High horsepower can be tamed with the proper torque, power band, and gear ratios, but it really isn't necessary for a street car to be able to smoke the tires at any given moment, or reach the speed of sound! Yes, it was a blast for a short while, then I realized how impractical the car really was on the street.
I hope that those who plan on mega high horsepower engines
for their cars, have their life insurance paid in full. Not to be putting a damper on somebody's dreams of a Mach 2 GT40, but I don't relish the thought of reading about someone's demise on this forum!

Bill

andys · 02-12-04, 12:11 PM

I think Bill's experience speaks volume in this debate. A nicely balanced package is way more fun (or less of a pain) to drive than the big HP stuff for the street. Rare also is the occassion when you can even apply all that HP.

Oh, that's right, we're discussing turbo's......It is possible to build a tractable and well mannered V8 turbo motor with reasonably good power that is not so abrupt. (And) Keeping boost levels low would demand less of the bottom end both in terms of cost and longevity. It would also be driveline friendly. Even a bone stock 302 @ 5-7 psi would run quite nicely in such a light weight car. FWIW.

Andy

JP · 02-12-04, 12:38 PM

450hp is mega horsepower, especially in a 40!

Not this max HP deal again! [img]/ubbthreads/images/graemlins/shocked.gif[/img]

Kevin M · 02-12-04, 02:43 PM

Bill,

Thanks for the further info. Having a car go sideways at 90 MPH on a public road is possibly just a little more excitement than I for one need. [img]/ubbthreads/images/graemlins/shocked.gif[/img] [img]/ubbthreads/images/graemlins/shocked.gif[/img]

Just as a passing thought, the Mk1 cars ran with 390 HP in race trim. The Gulf cars ran both 302 and 351 engines making 440 HP and 460 HP respectively. And the Mk II cars had 485 to 500 HP (But were several hundred pounds heavier which offset some of that).

Bottom line, about 450 HP makes the car equal or superior to any of those cars when they were racing.

Kevin

John · 02-12-04, 03:18 PM

Yes, if I ever do build a car it will primarily be for sunday street cruising and perhaps an occassional trip to the local road course for autocross fun. Nothing that would ever require anything more than a very mild build.

While it is completely impractical... when I build myself a GT40 I'm sure I'm not really going to be thinking much about practicality though. [img]/ubbthreads/images/graemlins/wink.gif[/img]

That said, I don't plan on doing the TT GT40, but it was just a thought. Something that would really wow the crowd at the friday night car shows! [img]/ubbthreads/images/graemlins/cool.gif[/img]

I do like the idea of packing some 335 rubber out back though! I hope to do a little inner fender well cutting on my Camaro to fit in some 335s at some point.

Howard Jones · 02-12-04, 03:26 PM

The Canam mk7's and 917-30's made 750 and aprox 1000 Hp, weighed about 1600 pounds and required the likes of Mark Donue, Mario Andretti, Denny Hume and Jackie Steward to drive them. The Porche had too much power even for them and thats why the series changed formula. F1 cars reached their power limmit at about 1500hp and Indy cars at about 925. Think about who those guys were! Enough said? Stick with <400hp and enjoy the car instead of being affraid of it. Really.

PReese270 · 02-12-04, 04:00 PM

Having driven cars with turbos and superchargers, I much prefer a good old blower. Get the heat out of the engine bay and get better engine response w/o spool up.