stock 02' LS1 falls flat at only 250 rwhp baseline
08-02-2011, 01:18 AM
#1
TECH Regular
Thread Starter
stock 02' LS1 falls flat at only 250 rwhp baseline I dropped my car off today at a local speed shop. I was excited because I have been planning my cam build for the last couple months. EPS 222/226 115+3 .597/.605 lift I believe.
Its an 02' m6 WS6 with a lid and catback being the only power mods, the rest being suspension.
The baseline dyno was discouraging.
The car would make decent power up to 3800-4k and fall completely flat on its face after that. It made a max of around 250 RWHP at around 4k rpm and then completely cliff dives after that.
My mechanic who has been working on LSX motors for the past decade said it could be a collapsing lifter or the Mass Air Flow Meter.
I wish I had the chart to post up so you guys could get a better look.
But what do you guys think? Could it be the Mass Air Flow Meter that would cause that huge of an impact?
Or even worst a collapsing lifter? wouldn't i have noticed this whole time I've been driving the car if it was a lifter?
Its an 02' m6 WS6 with a lid and catback being the only power mods, the rest being suspension.
The baseline dyno was discouraging.
The car would make decent power up to 3800-4k and fall completely flat on its face after that. It made a max of around 250 RWHP at around 4k rpm and then completely cliff dives after that.
My mechanic who has been working on LSX motors for the past decade said it could be a collapsing lifter or the Mass Air Flow Meter.
I wish I had the chart to post up so you guys could get a better look.
But what do you guys think? Could it be the Mass Air Flow Meter that would cause that huge of an impact?
Or even worst a collapsing lifter? wouldn't i have noticed this whole time I've been driving the car if it was a lifter?
08-02-2011, 01:04 PM
#4
TECH Regular
Thread Starter
the shop has it, typcially can they just email it to you? The'yre tearing into it today to swap everything out. Hopefully its nothing major. I'll post up the graphs once I get em.
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08-04-2011, 05:30 AM
#9
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Thread Starter
08-10-2011, 09:47 AM
#10
If I understand the way the '02 PCM work it will only reference the MAF up to 4000rpm @ WOT, beyond that it goes into "speed density" and simply aims for the commanded AFR.
For starters clean the MAF sensor (that means tearing it down and cleaning the sensors elements with the appropriate cleaner and some Q-tips). This is extremely helpful for those of us running oiled air filters. This will eliminate that variable.
You'll want to have the car scanned/datalogged on a run to look for any mechanical issues that would be picked up by the engine's sensor. You'll be looking for things like ignition KR, Inj DC%, failing O2s, etc.
After that you are going to move into mechanical problems like busted lifters or rocker arms, bad spark plugs, coils, plug wires, weak valvesprings and so on. Remember that we need 3 things for an ICE (aka a glorified air pump (air in, air out)) to run: air, spark and fuel...
For starters clean the MAF sensor (that means tearing it down and cleaning the sensors elements with the appropriate cleaner and some Q-tips). This is extremely helpful for those of us running oiled air filters. This will eliminate that variable.
You'll want to have the car scanned/datalogged on a run to look for any mechanical issues that would be picked up by the engine's sensor. You'll be looking for things like ignition KR, Inj DC%, failing O2s, etc.
After that you are going to move into mechanical problems like busted lifters or rocker arms, bad spark plugs, coils, plug wires, weak valvesprings and so on. Remember that we need 3 things for an ICE (aka a glorified air pump (air in, air out)) to run: air, spark and fuel...
08-14-2011, 01:12 PM
#12
TECH Regular
Thread Starter
well after swapping out the entire valvetrain/lifters along with the cam everything was back up to speed.
The final dyno numbers were 364.9 rwhp and 346lb ft. see link on the results
https://ls1tech.com/forums/dynamomet...3-results.html
On the dyno chart there were no drops or slight dips at all at the 3800 rpm. The lifters looked fine when we pulled them. who knows, valvetrain maybe? either way I'm satisfied with the results.
The final dyno numbers were 364.9 rwhp and 346lb ft. see link on the results
https://ls1tech.com/forums/dynamomet...3-results.html
On the dyno chart there were no drops or slight dips at all at the 3800 rpm. The lifters looked fine when we pulled them. who knows, valvetrain maybe? either way I'm satisfied with the results.
