danglerb

Stock 4.5L is about 175 to 180 rwhp is it?

seagul extra

Imo000 I had it dynoed at Marken Performance, they are on Ottawa St. in Kitchener. I am just looking at the chart now and one thing I am noticing is the air fuel ratio's. From 2000rpm to about 4500rpm it is just under 13 but from 4500 and up it quickly drops to below 12. I will report back from my next run on this too. I believe the porken s300s chip will stop it from going as rich on top.

Cosmo Kramer

295 doesn't sound unreasonable to me for a 5 speed car with an x pipe. On the 928MS website they have before/after dyno chart on an 85 automatic. It was putting down 250 hp bone stock, stock exhaust. Add say 7% for parasitic loss with the automatic brings it to 267 if it was a manual. Add no cats and X pipe and it would be hitting the 290's which is where you are at.

You have plucked most of the low hanging fruit already by pulling the cats and adding the X pipe. The chips will give you more peak HP, but going from 12-1 afr to 13-1 afr might net you 5 - 10 hp.

Another factor is the temperature, if you go to dyno in the fall and your previous run was on a hot day there will be a significant improvement. If conditions are the same I think you will hit 310 with the chips and other additions you have done.

Now if you really want that thing to go, let's talk forced induction.

PorKen

I would like to see 320 someday. Don't fret if you don't hit that though. I think there is a bottleneck in the intake(?) which has limited my max to around 315 rwdjhp. (The intake starts showing an increase in vacuum after 5000 rpm.) Torque is much improved with my chips, both in peak at around 2700 rpm, and lots more average.

I've seen as much as 7 hp for the belt driven fan on the dyno (cut belt between runs), but it depends on coolant temp, as well as how much silicone your fan has left in it. There is a tradeoff in not having the fan, though. The belt fan keeps the engine nice and cool, even at idle.

The S3 is very sensitive to air temp. Ideally, you would like to see 90°F airbox temps for max performance, but this is tough to do on the dyno. Anything over 120° and it will lose quite a bit of power. If you can, bring a IR thermometer to record the coolant bridge, and airbox temps.

Bill Ball

Low 12s/high 11s could be close to on the money for peak power.

Mike Frye

I thought that was the case too.

I'm logging the AFR in my setup and Ken has the 'Racer' chips kicking it to the low 12s when the WOT kicks in. I think he said it leans out a bit near redline but I haven't been able to confirm that. In my tests I haven't been able to keep the pedal down at WOT for very long and so far the highest I've logged was about 5200 before I had to lift (and look around!).

I guess we'll find out in the next week or two...

PorKen

An overrich mixture works well at low rpms for torque. Air speed and cylinder filling isn't ideal at lower revs so the extra fuel ensures that the available oxygen will be used. As rpms increase, there is more complete combustion, so the AFRs can go leaner. (At high rpm, around max HP, extra fuel displaces air, too.)

On both versions of my chipsets I shoot for low 12's at 2000 rpm, up to low/mid 13's at 6000 rpm at WOT. The 'racing' version takes advantage of a larger spark plug gap using non-resistor plugs. The larger gap makes for more complete combustion, so it needs more fuel for the same AFR, and makes more torque overall (= more hp).

Darklands

I think 320 rwhp is a very high number.
I fixed last week my power loss after the complete intake refresh and the installation of a 80 mm tb.
What a long way before I found the mistake.A broken vacuum connector and so no v. at the computers.
So my last run before the 80 mm tb was 327 hp at the crank.
I lost 20 hp with the disconnected vacuum lines.


I have yet the TÜV exhaust ( stock with metall cats) under the car and think I lost a little bit power.Top speed is between 255-260 km/h measured by GPS on Autobahn with this setup.

I need a new set of cats and must repair my xpipe because the exhaust clamps are very bad engineering.
After this mods I go back to the dyno.
I´m a lucky guy if I reach 345 hp/crank.

GregBBRD

There are generally two different dyno calibrations, these days. One has "real" rear wheel horsepower and the other has "optimistic" rear wheel horsepower. Most of the dynojet owners found out that they sell more dyno tests if they use the "optimistic" setting, so it is not uncommon to see cars that make more rear wheel horsepower than they ever had at the crankshaft....

The reality of the whole thing is that "loose" dynos get far more business than "tight dynos. So, the dyno operators learn when things need to be loose and when they need to be tight.

This even applies to engine dynos. Locally, there are 3-4 big engine dynos, which vary about 40 hp...on a mild small block Chevy "test" engine.

One of my friends who has a engine dyno words it this way:

I've probably dynoed 20-30 911 turbo engines that make over 600hp...and yet I've never actually seen one that does!

Imo000

The shop that the OP used is pretty much the only dyno in the area (60 mile radius). Up here dynos are not nearly as common as south of the border so, your theory might be true.

I was planning on talking my home made contraption to it one day but if I ever will, and it shows more than 360RWHP, we'll know the numbers are optimistic. All the 1/4 mile data calculations of 13.8sec, show 400hp at the crank or 360 at the wheel.

danglerb

Traction makes ET too variable for a good HP est. What seems most consistent is trap speed.

Darklands

@Greg
I think the Bosch dyno at my dyno shop is realistical.
But many people have irrational wishes for the goals of a mod.
Here´s the last dynorun with Ken´s chips and a xpipe with race kats.

I think intake restrictions hold the engine back over 5000 rpm.
So I install a 80 mm tb from a 928 S2 and thinking about regrinding my spare set of 86.5 cams.
The art is holding the torque at slow and medium rpm and open the engine at high revs.
I´m to much amateur for the right decisions and need advice.
The run is in 5th gear. Crank HP!

Imo000

Don't worry, all the figures, including the ET, were plugged into the calculator. Did it on 3 different sites and the all came back 360hp +-5hp.

Shane

Those numbers are not unreasonable. I've seen 281rwhp with a stock w/cat 5sp using AA chips and 3rd gear. Karsten has the gearbox for getting the good numbers by being able to use 5th gear. Most US 5sps are stuck using 4th as the 2.20 gears will overspeed the dyno thus blowing the run. US autos have to use 3rd.

Key to getting peak HP from the '86.5 is good sensors, eliminate any intake leaks, vacuum leaks, get solid grounds, check your cams, and buy some balanced injectors, and reduce or eliminate the parisites that drain your HP. I've found that getting rid of the crankcase vent to the intake helps.

I've seen an increase in HP by adding the RMB, but that was on the Murf setup and the stock muffler was "plugged"!

320rwhp is not unreasonable...

'86.5 rules!!

Darklands

My graph is crank hp!
But I have the low compression euro S3 !;-)
My steel RMB is an ugly bastard, one year in use and rust all over there.
On high speed autobahn rides my oil consumption is very high, I think I need a provent solution for this problem.