Mike Frye

This does look really cool, I wish it would work on my car.

Is anyone else surprised that the S4 in question was only pulling 282 RWHP with crossovers and high flow cats? I don't know what that translates to at the crank, but I thought the S4s were up in the 350 range when they were stock. I don't know, I'm just wondering.

What do these numbers translate to in Crank HP?

AO

I believe the stock '88 S4 was rated at 320 Crank HP. For an auto, we typically use an 18% loss factor (15% for a manual) so a bone stock factory auto car should dyno at about 262RWHP. Ed's mods have brought him about 20RWHP - then he added the Black bird which gave him an additional 11~12RWHP.

If we re-calc back to crank HP, Ed's got about 358 crank HP.

hacker-pschorr

Tim Murphy's wife's car put down just a hair over 260rwhp before the blower or any other mods.

Bret928

$700 uh? Hmmm? I think it would work pretty good on my 78 with it's Y-pipe (no cat) & the Borla exhaust. Probably won't see 11 hp but I'd be happy with a 6-8hp gain.

Mike Frye

Thanks Andrew,

So in fact the Blackbird is probably good (in this instance) for 15-20 hp at the crank? That's comparable to what you get with the crossovers with high flow cats, for the same kind of investment.

So you're OK with about $100/hp. That seems like a lot. Maybe losing some extra weight (from the car, of course ) would give more of an advantage than gaining HP.YMMV.

Didn't Mark Kibort post something about the relationship between weight loss and the effect it has on hp. I forget the numbers.

AO

Only if you're running Amzoil.

Bret928

Didn't say I'd like shelling out that amount of money. $700 bucks for something like this compared to some of the expenses I’ve had recently almost seems trivial. Guess I’ve become insensitive to popping for Shark bits.

Or maybe I'm still just in shock?

IcemanG17

So any properly running S4 can put on a blackbird, Xpipe & AFR or sharktune to gain close to 40whp & 40 torque.....not bad......a 300whp auto S4 for say $1350.....($450 xpipe, $700 blackbird, $200 AFR) I would pay that (if I had the $$$) :>(

Lizard928

I was kinda shocked at the figures as well,

Porken put down 298 RWHP and 299RW FT LBS iirc and his is completely stock, just with chips, that is a 86.

I put down 296.5 RWHP and 316.3RW FT LBS with my MS and EDIS again on an 86 engine.

Both of those cars have the stock airboxes.

hacker-pschorr

When quoting dyno numbers, can we all agree to list the type of dyno and calculation factor?

It can vary up to 10% or more.

Lizard928

Both were on Louie's Dynocom.

hacker-pschorr

What was the correction factor?

I don't dispute the numbers at all (I don't know much about the 85-86 engine). Just curious.

IcemanG17

Right....but Louie had the same dyno run listed with two different correction factors on his car at SATL....one showed 584whp.....the other 564whp...exact same run...just different corrections...one was SAE....I forgot what the other was....

Plus almost 300whp on a 85-86.5 is very high......considering the engine was rated at 288 stock & most tend to dyno around 240-250whp bone stock...

Imo000

That's just what Porsche was publishing. Every indication to me shows that this number is way to low for the early 32V engine.

First I thoght my '85 was a facytory freak but over the years I've seen time and time agian the 85-86 32Vs to put down some serious numbers (more than they should).

Im bone stock configuration (stock everyting even the 225 tires, full weight with spare and tools) I pulled consistent high 13 secs in the 1/4 mile, with a best of 13.7. That's a lot more than what a 288hp 928 should do (solid high 13s are well into the GTS territory). With only a set of chips and nothing else, the numbers wend down to 13.5sec.

hacker-pschorr

Brian,
The other is most likely STP. IIRC STP is the higher number.