I have a built 2.0L GSR engine in my '00 GSR. 84mm Benson sleeved, 9:1 CP pistons, Pauter rods, LS crank (1972cc). Assembled by myself. Stock GSR head and cams. Stock GSR intake and exhaust manifold. Test pipe and Apex N1 exhaust.

Ive broken it in NA. Tuned by myself with AEM EMS, AEM wideband, and RC 550cc injectors. Compression test numbers are 200, 190, 205, 200 after 1,000 miles. Burning no oil.

My question is what kind of power would you expect a 2.0L 9:1 GSR engine to make NA? I had it on the dyno for a short period of time. However due to an alternator problem I only got 2 WOT runs. I dyno'd 145whp and 100ft/lbs. I expected more than stock GSR power.

Low end and Mid range power is great, better than stock. But after 6 - 7k the power just dies off. Sorry I dont have my dyno graphs to post. AFR is around 13.0 at max load and timing is 29.1* at WOT, 8500rpm. VTEC is working, and my IAB's are opening.

I just wanted to get some experienced opinions on the matter before I put the turbo back on and boost the **** out of it. Is this sluggish top end normal for a low compression motor or is this prelude to a bigger problem?

 

Despite the fact that you went up in displacement you went down more than a full point in compression. Stock GSR intake manifold may be hurting you a little bit, Along with the stock exhaust as well.

 

So you think its normal for the less than stock HP and torque?

Wadzii (Jdogg) thinks the stock GSR cams cant feed the 2.0L with enough air at high rpm.

 

i'm actually interested in this too
im going to hit the dyno in a couple of weeks, going to be running a 84mm block Lsvtec, 9.5CR CP pistons, m22 cams, header and 2.5" thruout..i hope to make more then 160whp

need to save up for my turbo setup..

 

Whos tuning it?

 

lean it out to 13.5 or so AFR, that will put you up around 150-155 easy, plus you have lower compression pistons, To be honest, those are the numbers I would expect from your setup

 

You should try some more timing w/ the lower compression. But it doesn't sound too bad.

 

The full point drop in compression should be worth a loss of about 4% in power. It's not set in stone, but it's pretty damn close. Dividing your power by .96 you get 151 WHP. Unless an 84MM LS/VTEC at 10:1 compression is going to make 151 WHP something seems amiss. That torque is way off, that's down atleast 30 ft-lbs at peak compared to most LS/VTEC dynos. Try and get your sheet up.

 

You think 1 full compression point is only worth 4%? That seems very low.

I didnt get a chance to really begin tuning on the dyno. My map is only street tuned. On my 2nd run I retarded my high load ignition by 4* and picked up 5whp. So I dont think I can run any more timing than I am. However Im sure I can pick up some power by leaning it out to 13.5.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">You think 1 full compression point is only worth 4%? That seems very low.

I didnt get a chance to really begin tuning on the dyno. My map is only street tuned. On my 2nd run I retarded my high load ignition by 4* and picked up 5whp. So I dont think I can run any more timing than I am. However Im sure I can pick up some power by leaning it out to 13.5.</TD></TR></TABLE>

If you think you lose a lot more than 4% you've been reading too much honda-tech

Swapped out pistons on a buddies LS1, went from a -2CC flat top piston and 9.8:1 compression to a -16CC piston and 8.5:1 compression. Lost a full point and a half of compression, power dropped from 440 RWHP at peak to 422 RWHP at peak, didn't touch the timing didn't touch the fuel, both days were pretty similar weather. That's about a 4% loss in power, all across the rev band, for a little over a point and a half of compression. The consensus on H-T is shifting towards the "9:1 is almost too low for street motor" and that you're going to lose so much power off boost unless you build a 9.8:1 or 10:1 compression street turbo motor. Anyways, 4% sounds like a good figure to me, you really shouldn't be losing a whole lot more than that for a full point drop in compression. I think posting your chart and your timing map would help, something seems amiss for your 84MM LS/VTEC to be down 30 ft-lbs of torque compared to some stock block LS/VTEC's I've seen.

 

Well it could very well just be the tune. Im not a professional tuner. Im just trying to find out if there is anything mechanically wrong with the car. This has been holding me back from putting the turbo back on. I will try and get the dyno tomorrow.

 

Ok the guy at the shop didn't save my dyno charts. Thats ok they really wouldn't have shown you much anyways. Its just a pathetic low power curve thats all.

Yesterday I inspected and redid my timing belt on a hunch and it looked a little off. After many attempts I realized I could not get it anymore perfect. My block was decked a few thou so thats why its not perfect but I doubt its responsible for my extra low power. When the cam gears are lined up the crank is about 2-4* ATDC (not very much).

After that I took it for a test drive and listened carefully. The engine is real powerful up until 6k when I have the AEM to activate the IABs at. I hear a slight note change in the exhaust but after that point the power just sucks ***. I can hear the engine almost wheezing and sounds like its not moving as much air. Even tho the AEM says the IAB output is ON I do NOT hear the cold air intake roar I used to get from the IABs opening when I was stock.

Taking Jdogg's advice I pulled the vac line off my IABs. Apparently this makes them open all the time despite the actuator being in the same position it is during idle with the vac line connected?? I don't understand that part... However another test drive proved that after 6k it did feel stronger. Not a huge difference but the engine def sounds healthier past 6k.

I was not sure if leaving the vac line off the IAB actuator meant that it was open or closed so I tried the opposite. I zip tied the actuator arm in the up position. Another test drive but no performance difference from last time. Id expect a drastic change between the two as one had the runners closed and one had them open. I don't get it.

Therefore Im leaning towards the IABs as the culprit. Anyone have thoughts on the IABs?

 

Im also still running my turbo plugs. NGK BCPR7ES-11 gapped at .032" I know they arent ideal for NA and sometimes my car sputters under low load, most likely caused by the spark plugs. Do you think they are responsible for my missing 25hp? lol

 

Im turbocharged. Running 7psi. From leaving the IAB open ( unplugging Vac from the actuator ) (same thing with zip ties) and I notice my boost feels VERY smooth and strong all the way up! With the IAB in place... I notice, it felt like crap in lower RPM levels...Considering boost was wanting to be pushed in, yet.. The IAB was closed..

I think leaving the IAB open gives more air in.. Will hurt on lower torque levels.. Tho.. Not much..?

Goodluck. With the car.. Just boost it already!!!!!!!!!!!!!!!!!!!!

 

When I disconnected the vac line, the actuator is down. When I zip tied it, the actuator was up. Which is open? How can they be open in the down position? Thats the position they are at in idle.

There was virtually no performance difference between the two. Any alarms going off?

 

Weird.. hmm

When the car is completely off... The IAB is left OPEN.
On Idle/or Car on... The IAB is CLOSED (due to vac)..

Not sure which was is the position... "up" "down"

Ill check tomorrow. Lolz..

 

A few people are telling me I need cam gears. I cant believe .003" milled off my deck is going to throw it off this much! As stated above I cant get the timming belt to line up perfectly. When the stock cam gears are lined up the crank is about 4* ATDC. Anyone have any idea how much power thats costing me? Perhaps thats the bulk of the problem.