pig4bill

I've seen a lot of ads for various bolt-on performance mods like turbos, chips, fuel injectors, MAF, exhaust, etc. They all promise a certain hp gain. I know if you put them all on the gain is not cumulative. Even so, it seems like 100 hp gain is not hard to achieve. Maybe even 150 hp. Is this so? Do any other changes have to be made, such as internal engine changes? Can the driveline stand it? I sure seems like an economical way to go versus hunting up a 3.6 Turbo.

Steve Weiner-Rennsport Systems

Hi:

There are certainly a lot of things that can be done to the 3.3 litre Turbo that will increase power. You are also quite correct when you state that these things are NOT cumulative.

A few things about these cars must be mentioned here,......

Its not hard to make big power from these engines, its hard to make big power and retain some semblance of longevity. Nobody wants a grenade,......

Further, what you really need is usable torque and throttle response, not power just at the top end of the RPM range. This is why the '94 3.6 Turbo is so neat, its a bigger engine coupled to a decently geared 5-speed transmission.

That said, we have done some street Turbos that will run harder than the '94 3.6 car however, this is not inexpensive to do. Turbo engines are simply airpumps and to get more HP and torque, you must move more air in and out. To that end, we have done engines in this configuration that retain stock type durability and reliability on pump fuel.

1) 3.4 or 3.5 litres at 7.5 to 8:1 CR
2) Twin-ignition (a must)
3) SC or 964 cams
4) B&B headers and muffler
5) Extensively modified heads, intake manifold and larger billet injector blocks
6) C2 Intercooler
7) K27-200 Turbo
8) ARP Rod bolts
9) Aase racing valve springs and titanium retainers
10) Airflow meter and fuel distributor modified for more air and fuel under boost.

With very careful assembly followed by dyno setup and run-in, these engines make an honest 450-460 at the flywheel and are rather intimidating to drive. We build up a custom Sachs clutch with the later, lighter flywheel that will handle this kind of torque without stress.

The best part is that these engines are making 300 lb-ft of torque at 3000 RPM and this makes them very drivable. Boost pressures are not over .8 bar.

pig4bill

Thanks for your input. Almost none of the stuff you listed is bolt-on, which is what I'm after. I don't want to sink 5 figures into an engine that still won't keep up with a Supra.

Using purely bolt-ons, how much power do you think I could add without affecting reliability to a large degree? Thanks.

BigPorscheGuy39

If your 930 cannot keep up to a Supra I'd suggest you want a complete engine overhaul and maybe make sure you don't have something seriously wrong with your gas pedal placement. My 931 can easily take a Supra and it's half the size.

You sure that wasn't a typo?

Steve Weiner-Rennsport Systems

Bill (in San Jose):

Soms of the things that I listed there ARE bolt-on,.......

Turbocharger
Exhaust headers & muffler
Intercooler

Changing these things will provide a modest increase in power however, my goal was to show that all these components work in concert with each other to increase airflow and maintain reliability.

Establishing the health of your engine should be the first priority before undertaking any performance upgrades and I would encourage you to have a compression & leakdown test done before anything else......many times we find things like broken rings from insufficient octane fuel and these things must be dealt with before moving forward.

Lastly, there are some Turbo Supra's that are very fast, for a short time. A properly done 450 HP, 3.4-3.5 litre 930 will give them a VERY bad time for a very long time.

pig4bill

Once again I appreciate your input. Care to quantify "modest increase in power" of your listed bolt-ons? I know the motor has to be checked, etc. I don't have a car yet. I'm researching which car to base my project on.

BTW, people shouldn't underestimate Supras. Stock, they are as quick as 3.3 930's (320hp, 0-60 5.0) and easy to get to 450 hp. 500-600 reliable hp is not that hard to get, and the radical ones are doing 700-800 hp.

aka 951

If you want to go fast for less cash you should consider a 944 turbo (951). 325-350 wheel hp is really not that difficult with bolt-ons. I run 20 psi on pump gas in mine with stock internals, along with MAF, Turbo, and some other goodies. Total investment - less than 12k including car.

Erick

Steve Weiner-Rennsport Systems

Its always difficult to make accurate HP projections on any engine, and even more so on a used one.

I would tell you that installing the B&B Header/muffler system on a 930 will not only increase the overall torque, it will make a significant reduction in throttle lag, something these cars really need. I would further tell you that a larger, more efficient intercooler will help keep the engine making its rated HP, a lot longer by containing the charge-air temperature increases over time. I would recommend not increasing boost pressures over 1.0 bar

There is no problem in getting any turbocharged car to make big power, the challenge is keeping it reliable and not compromising durability. Anyone can build a "grenade" engine that will produce impressive numbers on a dyno.

Good luck in your search!

[ 06-28-2001: Message edited by: Steve Weiner-Rennsport Systems ]

pig4bill

Okay, so the real answer to my original question is that internal changes DO have to be made. I think a 930 is not a good candidate for what I'm after and I need to keep looking.

ZCAT3

Hey pig4bill - have you thought about looking for an already modified 930? Given your goal is overall power, perhaps you should find someone who has already done all the work for you. I see 80s 930s advertised all the time in the 30K + range where people have already done the mods required to get the car abover 400 HP. There is a nice slant nose on eBay right now that is in that category.

pig4bill

The problem with going that route is it would be hard to determine if the adequate longevity mods had been made to go along with the power. I guess I've been spoiled by reading about the modern turbo motors in the Supra and VW that are over-engineered in the bottom end and can be boosted considerably without concern for the internals.

But just for grins, maybe Steve could throw out a ballpark figure for one of these "built" 930 motors. Please keep in mind it has to pass California emissions. Thanks.

JBH

I think the statement that one can boost a Supra to 500-600hp and not be concerned for internals has to be challenged.

While modifying a Supra may cost less than a Porsche taking a stock motor and nearly doubling the HP is going to have an impact on longevity. There is no way that it can't. Building a car that lasts under that kind of stress has to take some serious money.

pig4bill: you don't state your objectives for all this HP - is this strictly a straight line acceleration issue? If it is, then I think the approach is different than a car that you build to take on the track and street.

When it comes time to stop and turn, I'll take a Porsche Turbo over the Supra Turbo every day.

Steve Weiner-Rennsport Systems

The bottom end of the Turbo motor is quite well equipped to handle the extra power available in a CIS-equipped Turbo, if the rod bolts are upgraded to ARP or Raceware stuff.

As to ballpark figures,.......ball park only here,.......When a Turbo comes in needing a complete rebuild, and the owner wishes the "Full Monty" street engine setup. this will typically run in the $ 20-22K range. This would be a 3.4 litre, twin-plug, 450 HP street Turbo at .8 bar and very reliable.

pig4bill

JBH, yes, I'm just looking for staright-line speed enhancement. I have no intention of taking it on the track - that would be just about my last choice for a track car. Too fast, too hard to drive, and too expensive to fix. Yeah, I'd rather have a 930 than a Supra too, that's why I'm making these inquiries.

As far as a Supra motor living on 500-600 hp, I can only go by what the guys with those cars are saying. There are quite a few making over 500 hp on the dyno (with stock internals), which is approaching 600 at the crank, and I've yet to hear of a blowup.

pig4bill

Even a seemingly innocuous modification as replacing the rod bolts requires a complete engine teardown if I'm not mistaken. A few thousand bucks, right?

Thanks for your help Steve, and putting up with my nearly endless stream of questions.