eastside

I have a 89 930 with k27 turbo,ruf intercooler,ruf exhaust. Stock cams headers. I put the car on a dyno and pulled 275 hp. My Porsche manual shows about the same sae net hp for a stock 930. Should I have expected more hp from these mods ? Seems like I just blew some cash for nothing. Or do I need to go the cam ,header route????

Peter Carroll/Toronto

On a dyno the intercooler isn't going to do much because you don't have enough airflow. And the K27 has more to do with throttle response than horsepower.

Does it feel faster when you drive it? If it does, it probably is. Also who says you car was putting out the same hp as new in the first place? It's 14 years old. If you didn't do a baseline to compare against, maybe you did get more power.

I suspect the really big gains you're looking for are in the headers. They'll also get rid of a lot of lag. Cams will help too but do SC or C2 cams. Group B cams will give you more lag.

You should also install the Andial fuel enrichment device. This will prevent you from wearing out your engine prematurely as I did. I would also install a "real" mechanical boost gauge in place of the clock and a Halmeter (air/fuel ratio meter). Both will help you know that your engine is operating safely and not slowly self-destructing...

Dean

I think the factory rating is engine Hp and I think you did rwhp. I read that there is about a 15% loss in the tranny.

eastside

Thanks for the response guys. I have adj boost and Ruf (vdo) gauge. Was not aware of the Halmeter . Will have to look into that. The factory rating is 282hp at 5500rpm and it is Sae net (rear wheel). The dyno techs told me to figure about a 22% drivetrain loss. Eastside

Bruce M.

That dyno loss figure is way high. Makes me suspicious of whether your dyno guys know 930s.

Drivetrain loss on a 930 is pretty predictable--15% or a little lower. Mine's around 14%.

The 22% sounds like a number for a large, front engined car like a Vette, or something.

ZCAT3

Eastside - the 282 factory HP is at the crank - not at the wheels (all Porsche stated HP number are at the crank). So if you saw 275 at the wheels, that is about 324 at the crank based on the standard 15% drivetrain loss. Sounds to me like your car is doing quite nicely with those mods.

Geoffrey

My engine was put on an engine dyno (521hp), then on a chassis dyno (443hp). That shows about a 15% loss with a G50/50 5-speed. I'll echo that 282hp was at the crank, not the wheels and think you'll find a large improvement with a better exhaust.

eastside

Glad to learn that the published hp is at the crank. If you think exhaust will also help ,what do you guys recommend-run. My mech swears by Ruf .I asked about B&B. He did not think too highly about them . Thanks again for the input. I am trying to formulate my next move. Eastside

John from WA

I used GHL for mine. They have a decent design (if you get the performance muffler) and a great customer service experience. They take care of there customers. The sport muffler is good for 40hp over the normal muffler and ten hp over a dump pipe (elbow), not sure compared to stock muffler. Ruf is, of course, good stuff. I've seen B&B's fail with little customer service support.

John

Louis

Where can you purchase a good mechanical boost unit? Where to install?

MHT

b@b stuff usually ALMOST fits.

KeithC2Turto

What boost sevel were you runing!

JBH

Keith's got it - I think you may be down on boost. Go to 1 bar with appropriate A/F mixture and I think you can do better than your dyno number.

eastside

The dyno run was at 6500rpm and 1 bar (according to my guage) also I had the a/f mapped. It was slightly lean. Who knows how accurate the boost guage is. Probably should have checked that also. Car runs great . But I think it is probably close to what it pulled on the dyno with the current set up. If I want more hp I guess its time to go the cams ,header route.

ZCAT3

Well if you have the stock boost spring in, it should not be 1 bar. The boost gauge in the dash is not accurate at all. My stock spring produces about .7 bar (.8 is what the factory supposedly set these at), but my gauge will read 1 bar. I have an electronic boost controller that gives me a very accurate boost reading, so I do not rely on the dash gauge (other than to see when boost is being generated). You should have your shop hook up an accurate boost gauge to verify your spring rate.

P.S. If you need to change your spring I have an Andial 1 bar spring (that tested at 1.05 bar in my car) that I would let go cheap.