Mattman928

On a 1990 GT, what are soe of the things I can do to boost horsepower? And what are the approximate costs?

Thanks all!

ErnestSw

There are two main categories of horsepower gains:
1. The ones that come from the horse's mouth, in other words the ones that have been proven and quantified on a dyno.
2. The ones that come from the other end of the horse like the wires, filters, plugs, and magic formulas.
Some, like after market chips, are a little of both.

Shane

Click on the search engine at top right corner of page. Type in Hp gains, super charger, turbo charger and any other conceivable phrase dealing with horse power gains. There is a wealth of info in the archives on this subject.

Chris

One of the more commont topics, 1st thing is to get a baseline as to your cars current status. Go find a local dyno, then before you do any mods make sure your car is up to snuff.

Flappy, fuel delivery (pressure,filter and injectors), ignition (plugs,wires,caprs,rotors) etc etc ...

Now your car is working as per factory, go explore prior listings. Exhaust seems to be the most bang for your buck, after that its how fat is your wallet ?

Have fun.

Chris

John..

Maybe look into a set of header pipes and cam work? On that new of a car, I would not supercgarge or turbocharge it....limited production, it may have historic value some day.

bcdavis

Headers, exhaust, and chip, are the simple mods that will not cost too much...

Beyond that, you are talking major engine work...

ErnestSw

Devek has produced OVER 450HP from STOCK headers. They have dyno proof that the stock headers are NOT HP restrictive.

Jim Nowak

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Devek has produced OVER 450HP from STOCK headers. They have dyno proof that the stock headers are NOT HP restrictive.

</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Funny that Devek should advertise that their headers make more horsepower than the stock exhaust?

<a href="http://www.devek.net/index.php?page=nfo_pro_per_headers&cat=2" target="_blank">http://www.devek.net/index.php?page=nfo_pro_per_headers&cat=2</a>

ErnestSw

My mistake. The Devek post referred to the INTAKE manifold.
Slight diference!

bcdavis

Well, still...the intake manifolds on the Devek cars are usually the s4 intake manifolds. Which may indeed be non-restrictive. But many people have the s2 cars, which has the "Spider" manifold, which in Europe, was bored out to be larger, and it increased power. There are not many choices for people when it comes to manifolds anyhow. But if someone was to ask what they can do to increase HP, they *could* indeed find a few ponies by running the Euro intake, or a set of extrudehoned US intakes... The early manifolds ARE restrictive, FYI... So are the early exhaust headers...

Fastest928

The best we have been able to acheive in a DEVEK based stroker with stock cams, modified heads, headers, cat and exhaust is 440 rwhp or about 520 crank hp with durability, serviceability and emmissions equal to the stock engine and improved fuel efficiency at cruise. Add DEVEK B1 cams to the equation, add about 20 - 25 rwhp. Add DEVEK race intake, add about ......ooops, gonna have to wait for the REAL dyno numbers first.

The average stock based stroker...no heads, headers or other mods other than a professional perfromance rebuild is 380-390 rwhp.

DEVEK headers, cat and exhaust is worth about 25-30 RWHP! There have been two examples of big number gains....but the above is more typical.

DEVEK big valve heads with mild port work is worth about 30-35 rwhp on an otherwise stock engine.

DEVEK B1 cams in a 5.0 l engine is worth close to 45 rwhp, however, loss of drivability, rpm for peak hp and tuning requirements prevents sale for street use.

Marc
DEVEK

bcdavis

Regarding intake manifolds...

With American V8's, they have many different manifold configurations, for the same small block V8, and same carb, all which produce HP and torque at different ranges. So even if people feel that Porsche did a great job with the stock manifold, and it is ideal at what it was intended to do, there are probably still variations that can be made to it's design, to make more power at different places in the power curve.

Anyhow, looking forward to some new Devek products and numbers...

John.

And I am waiting for Marc to build that twin turbo monster 928!

Brent 89-GT

FAST had their supercharger kits on sale this spring. $4650 for about 75 rwhp. Beyond that, you already have a hot rod version of the 928. You are running different cams and exhaust than a standard S4.

I have read that the chips for the '89 and up cars are pretty ineffective, no real gains. Exhaust can help as stated but, some systems get pretty loud. I kind of like mine with a stock, plus rear muffler bybass, set up.

I guess I figured that if I blew the engine I would go for a stroker kit. If not I would get the SC kit. Hopefully nothing lets loose, I would rather add the SC, it is much cheaper than a rebuild <img border="0" title="" alt="[Wink]" src="wink.gif" />

slate blue

Gordon Murray was recently interveiwed about engines and ways to achieve high engine power. He said he would always go for naturally aspirated. Then supercharged and begrudgingly turbocharging.

The way Devek has gone so far has been the way to go. I would never turbocharge a 928 personally. The engine bay has plenty in there already, I would like to see products that develop what we have.

You must remember that weight is a critical factor in preformance. The heavier you are the more power to just get equal straight line preformance and that does not take into consideration braking, and handling. Weight is more important than hp! The reason I bought an earlier car is that I didn't want such things as rear air cond.

Have a look at a Ferrari F40 it doesn't have carpet door trims or door handles.

So I would love to see products such as new manifolds and exhausts.

All the best. <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />