Today was my 1st time on a dyno. I didn't have as good results that I thought I would. But I think thats explainable.

Car & set up: '89 gtu, S5 n/a, around 16k miles on rebuild, mild porting, full RB exhaust, heat-shielded cone intake air filter, new (e-bay special) stage 2 clutch, red-line tranny fluid, good tires.

Issues that I know of: Bad o2 sensor (16k miles on it), same for spark-plugs ( i did clean them), running really rich, bad hesitations when cruising 3k rpm to 4k rpm.

Dyno results: Peak hp at 6350rpm = 131.4, nice "mound" on the graph from 5300rpm to 7300rpm, never going below 120.
Peak Torque at 4100rpm = 125.4, nice "mound" on graph from 3300rpm to 4800rpm, never going below 120.
3rd gear pull, btw.

Ill see about posting the graph when I can.

So I was hoping for 170hp to 180hp, Id be happy with just 160hp.
So I think the loss is because the o2 sensor, running rich, etc...

How much hp would be robed from a really rich condition?

If I got that stuff fixed would those numbers be in the same rpm range but higher?
I like where there at in the rpm range but just don't like that there low.

Maybe I just need to change everything like, plugs, o2 sensor, fuel filter, etc... But it seems kinda soon with 16k miles on those parts.

And Im thinking about getting a fuel controller to lean it out a bit.
This is my daily driver, I don't care too much about high performance and mods, but those #'s should be higher than that.

Any comments, Q, A ?

 

Toby I'm not 100% sure, but Richard said that his car running as rich as it was cost him at least 100hp. I'm sure I lost some due to running rich, too. Better than running lean! I'm interested to hear your results after the 02 sensor swap, I think it should be a night and day difference. Also I don't think 16k is too early to swap your fuel filter, in fact I wouldn't be surprised at all if that didn't hold you back today as well. That can make a HUGE difference.

 

Highly unlikely.


-Ted

 

Got the O2 sensor changed, took care of the hesitation.
Still running rich.

Anyway Ive grown to think that these cars come with 146hp for s4 and 160hp for s5 N/As, from researching spec web sites.
Is this a myth?
And what is that hp measured at, the flywheel or at the wheels?

I did a small search on dyno results for N/As. It seems that some have only gotten up to 150-170hp, and thats with some to alot of mods, like full exhaust, intake, fuel controller, etc.

I could understand If with those spec sites they labled those #'s at the flywheel. So when you get a stock N/A rx7 and dyno it at the wheels you get around 130hp.
Cause of drive-train loss.

What hp #'s should I be running with the mods I have?

 

Per Eli's post in my thread the S4 makes 146 @ the flywheel, because he said where I am at now is more than what he had when his was stock. So if that is what you have then your numbers were probably correct, aside from the running rich issue. Glad the mid rpm hesitation is gone!