Ok, I finally got some dyno time. Here's the before: http://members.home.net/flavour/3.jpg

Here's the after my rebuild (compression from 10:1-11.5:1 and balanced bottom end, new ignition, lightened fly and crank): http://members.home.net/flavour/2.jpg

oh and for those wondering if the resetting the ecu works, here's a baseline vs ecu reset baseline (no other changes): http://members.home.net/flavour/1.jpg

we ran out of time to work on the fuel settings. I was hoping to bump up the peak hp to 200 but ran out of time to try to get it there. My mechanic said we could get there but at the expense of midrange hp and I didn't want to do that. Is there anything I can do to bump up the peak without hurting my midrange? I know I should - more fuel from my vafc since its only at -3 right now. we ran out of time to play with it more but i doubt that will get me any more than a few hp.

I have type-s cams, is that why i'm losing so much torque at the end? is it obd2? any ideas? notice how my peak torque is much sooner than before. not that that's a bad thing, but that is what's keeping me from 200...

 

Horry Chit! That's like a 3-6 hp gain across the entire range! ... Just from reseting the ECU!

I've been waiting for someone to actually dyno that. I'm surprised that no one has dynoed the "ECU reset" before. When I do my next round of dyno pulls I'll try that too to get some numbers for comparision...

Nice plots, and very nice numbers. Some mild headwork should be able to help you on the top-end without sacrificing too much midrange.

Andrew

 

interesting...nice numbers
ever notice how H22A preludes with ignition have been dynoing much stronger than the ones without? I am beginning to believe that there are some real nice gains to be had with ignition on Ludes.

so with resetting the ecu, did you just reset it and immediately dyno it after you next started it up? Or did you let it idle for a while and then shut it off again and restart the car or what?

 

the only reason to reset the ecu is if you have OBD II right? 96 and up?

 

I just pulled the 7.5A fuse for like 10 seconds, idled it for 10 seconds, then did the run.

I do have a mild p&p, but the guy who built the bottom end said the p&p could have been done better, but wasn't worth the money to fix it up better, so I just left it. I'm done spending $$ on this engine, but I may be convinced to do the obd swap if I can be convinced there's another 10 ft lbs of torque across the band. You guys would not believe the difference between how the car felt before the dyno tuning (dyno 1) and after (dyno 15). We used the ecu reset as the base in the comparison 3 vs 15 so the diff is even greater 1 vs 15. The car feels much torquier and is a lot of fun to drive in the 2000-5000 rpm range, much more responsive. If I could do that again with the newer ecu then I'd do it for sure.

 

so what did you find helped the most for tuning? Using the V-AFC?
I am dynoing my car next weekend. I still need to install the V-AFC
I also would like to advance my timing and see how that helps or something.

 

All that gain is 90% cam gear and fpr tuning. I believe the cam gears are +5 -2 so lots of overlap going on there. We actually wasted a lot of time, but dyno time is cheap up here (about 35/hr in US funds) so I'm not too upset. I'd like more time to play with the vafc, we only had 2 runs playing with it! and found that 5000rpm vtec crossover was best, which is different than what other people have found...

I only wish I could play around with my ignition timing

 

here's a friend of mine with obd1... this is only bolt ons and he has nearly as much peak torque as me, granted its for a short period of time, but since I have a point and a half more compression, I would think I'd have a lot more...
http://members.home.net/flavour/obd1.jpg

 

so what did your friend do for his tuning?

 

mostly vafc, and some cam tuning. i dunno if they played with timing or not.

 

 

you actually choose the name "eminem"

 

any more comments? anyone with experience with obd1 or aftermarket ecu's - will they free up the top end and still gain torque all the way through?

 

I worked with Mazen (I think his screen name is 98luder) about 1 1/2 years ago on an OBD1 swap. At the time, only Sun had done the swap before. We were doing initial testing using my OBD1 P13 ECU and his wiring harness converter.

Mazen also had TypeS cams. He used a P72 GS-R ECU reprogrammed with copies of the maps that Yoshio from Japanese Automotive in Canada made for Sun's Prelude. He did some dynos. With the addition of an MSD ignition, the reprogrammed OBD1 GS-R ECU, and some timing advance, Mazen gained 9-17hp across the entire RPM range. That's a 9-17hp gain over his baseline with just I/H/E and TypeS cams...

Andrew

 

what did your initial testing with the p13 turn up? how come he went to the gsr ecu? were you throwing codes with just the p13 and harness?

 

Yes. On a 97+ Prelude without any other changes a P13 + OBD harness converter = CE light

It ran fine through. Idle was fine, and it pulled to VTEC. Dispite the CEL, the P13 did not go into "limp home" mode.

I don't remember the codes we were getting. I think one was the CYP Sensor. I'll have to check my notes. The reason for the CELs was due to the the fuel injector differences and the distributor differences between the 93-95 and 97+ cars.

Going with the P72 GS-R ECU makes this easier in that 1)they are easier to find and cheaper than a P13 2)It is designed for saturated injectors which the 97+ H22a comes with from the factory...

The problem with a GS-R ecu is that you need to pay to get it socketed and chipped and reprogrammed with fuel and ignition maps suitable for an H22a. The only two people in the US that have done this to my knowledge are Sun and Mazen. And they are both using the exact same maps.

Andrew

 

Well, I already have a P13 sitting in my basement. Some guy only wanted $100 for it so I bought it even though I wasn't sure if I was gonna use it. I just wanted to know if I needed it to be reprogrammed. So I guess not necessarily is the answer. It works, but the ecu knows something is fishy. I wish I didn't need to spend 250 on a freaking harness I wish I knew if it was the ecu that was killing some of my torque.

 

If you've already got a P13, you could go ahead & get a stage 2 Hondata system for like ~300 bucks. Some more dyno time, & that'd solve all your fueling. It sounds like you've got enough work done so that you're pushing the limits of any kind of stock fuel map - even with a VAFC.

And since you wouldn't need it, you could sell the VAFC to offset the cost of the adapter harness. You could sell off the FPR as well . . . .

I guess it depends on how close the nearest Hondata tuner is to you.

Just an idea.


[Modified by Daemione, 9:13 AM 11/6/2001]


[Modified by Daemione, 9:14 AM 11/6/2001]

 

I'm sure Rick has an OBDI engine harness plug. Let me trash your stock ECU and we'll make an adapter. Let me tell you, it was torture cutting my perfectly good stock ECU into bits just for that harness connector.

 

Actually, that's a serious offer. If you're afraid to trash your own ECU, find another 5th Gen ECU from someone whos done the swap, even if it's fried. If you can get the ECU and the OBD ECU connector harness from Rick for cheap we can make up the adapter in about 2 hours, if we can use Prelude-Type-Ss' adapter as a reference.

If you're not afraid to trash your own ECU, then we can make up an adapter for the cost of the OBDI engine harness.

 

Can you crop those smaller...