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09-23-2002, 01:53 PM
Ok, results are in. Some background first.

After a dismal dyno run in Nov '01, car was diagnoised with melted vacum/boost line from engine compartment to TurboTronics box and J&S Knock control box. This was fixed, a larger Bosch fuel pump from a Porsche 930 Turbo installed and a cold air intake was fabricated and installed. Car went from 242rwhp/295lb-ft to 305rwhp/355lbft @ 12.3psi. Nice. A solid 360hp/420lb-ft crank.

Over the last week I played with some settings on the knock control box, TT box and boost controler, and was able to get the car to run a peak 17psi. As a note, I couldn't figure out how the TT box did things, so it's settings were put to as delivered by Dinan for most of the testing. Put a total of 25 runs in. Seems to pull hard. Im not sure how the boost looks across the entire rev band, as the testing is done driving the car, and I can't look at the boost guage for the entire run, but peak was 1.21kg/cm2(17psi).

Dyno day, peak 316rwhp/375lb-ft @ 17psi? Mmmmmmm.... the wheels start turning. 4psi more and only a increase in 11rwhp/20lb-ft increase????? If Jarmo's site is right, 50hp fro every 3psi increase. I'm not close to that. Whats different from April to Sat. Well, alot I guess. I'll start to try and decipher what happened.

1) In April, the dyno test temp was low 70 deg F. Sat was 90 deg F and was a little hotter in the shop(it felt that way). Plus, my car was sitting in direct sunlight for 2 hrs before the dyno test. Pull it up, put a small fan only on the fog inlet. And ~4 minutes later, bang off a 3rd gear run and 30 seconds later, a 4th gear run. I speculate that the IC was much hotter than the April dyno. Maybe 50-60 deg F? My April best run was a 13 minute cool down with same fan in much cooler ambient. While the dyno can correct for temp/pressure, it can't compensate for the IC temp, but I still feel theres more to be had....

2) Tuning! The wheels are turning. Adjusting the retard on the J&S knock control box really dosen't help. Plus, the TT box's eprom has 14psi written on it. I specualte that above 14psi, the Dinan TT box is not doing it's job right either. Bill Yates, you know about this situation!

3) AFM. I'm thinking that even though Dinan put a stiffer spring in the AFM to better measure the increase in air mass, I bet it's maxed out at some point between 12.3 and 17psi. I don't know this for sure, but this seems make sense to me, as the dyno cart says the system makes very little power over the 12.3psi pull anywhere from 4k rpm to 5.5k rpm. Again, this is a guess, but it's just seems to make sense to me. I will try and test this theory before I pull the head. This means that the DME has no idea that increased air mass is being put into the engine. And the AFR readings seem to indicate this. The AFR leans a bit(but not badly) in the peak power areas. But never getting above 13:1. Buts it's not that solid 11.5 to 12.6:1 and lower for the April run.

4) Exhaust. I wonder how free my exhaust really is. I don't know in it's current from if it will support this kind of power?

Thats it. I hope to have the dyno scans up in the next couple of days.

Any comments is appreciated.

'88 535is Dinan Turbo Final Edition

Sweeney MA 86 635Turbo
09-24-2002, 07:23 AM
some things you may want to consider...
Air flow through the IC is restricted by the ABS pump.
Hot air off the IC is directed into the air filter.

09-24-2002, 12:19 PM
Impressive stuff, what turbocharger are you using? The reason I ask is if your turbo is not efficiently working at the air flow levels required then more boost pressure will produce very little gain. This seems to be the problem you are having.

09-24-2002, 07:18 PM
A friend's E30 Dinan 3 Turbo gained 35 hp at 5500 rpm and 40 ft/lbs or torque at 3000 by switching from the 325i exhaust to the E30 M3 exhaust. The 'i' exhaust was restricting the exhaust flow too much so the turbo wasn't exhaling to full capacity. These are actual dyno figures.

09-26-2002, 12:07 AM
The muffler is a E28 ///M5 unit modified by Dinan. The turbo bolts to the manifold and the downpipe is 2.5" ID. The ///M5 cat is a dual 1.5" ID in/out. The muffler is the same.

It seems that most people runing 400hp+ mostly don't have a cat at all and are using 3" ID single pipe systems ie, high flow cat with 3" and high flow muffler 3".

I'll have to look at this.


09-26-2002, 12:09 AM
TO4B 53. A 0.69 exhaust A/R P-Trim and H3 compressor. Where can I find a flow map for this?


09-26-2002, 12:10 AM
in the turbo section under CAIS. Dinan made a better cold air intake for the system.

But yes, the ABS does block some airflow. My project this winter is to move that IC to the front spoiler and get it out of the engine compartment.


09-26-2002, 02:24 PM
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Just a quick calc on the airflow you should be ~50-55 lbs/min airflow at a pressure ratio of close to 2.2 (17psi) so your off the map, same problem I have with my 320i turbo

Great torque but dies off up top, used to pull 7500 rpms easily with my low compression engine, now with the new engine and high compression (8.8:1) it struggles to 6500rpm with the same turbo.

09-26-2002, 02:38 PM
I was assuming you pulled to 6500 rpms, saw your dyno sheet and since you only go to under 6000 I figured 40 lbs/min airflow at 13psi (~2 Pressure ratio)
My calcs place your HP at 13psi at 360
17psi should produce 420hp ~44 lbs/min air flow at 2.2 PR

10-09-2002, 02:11 PM

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