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I have a 1999 camaro with a 6.0, 228/228 @ 110 LSA 0.600 Lift, mid rise intake with 102 mm throttle body, 243 heads exhaust side porrted and polished, full length headers, 3500 stall converter, stock 3.23 gears, and 25.67in tall tires. I made 389 at 5400 rpm and 471 @ 3850rpm. do these numbers seem reasonable?? this is just not a flat curve as far as torque goes. Let me know what y'all know.
Ok whatvyou are seeing us converter flash. Need to dyno with the converter locked. Peak power at 5400 indicates your cam might be off. Peaking way too early. Should peak near 6300
The rpm read a little low on Keith’s dyno when we did my lightning. It makes peak around 5300 on my dynojet but only showed 4700 on his. Torque Has always been ~600 in my truck, and hp is about spot on at the time I dynod. If you didn’t lock the converter that left some on the table but it looks like it’s falling off hard up top. Have you put a wideband on it ? Or logged for spark advance ?
Last edited by Fade2blk500; 06-12-2019 at 02:01 AM.
That is one of the most unusual dyno curves I have ever seen.
It peaks way too early and falls off a cliff.
Darth is right.
Camshaft was not installed correctly and I also think you have some serious valvetrain issues.
If I had a curve like that I would be checking pre load, pushrods, checking the valve springs etc.
Something is not right.
With a stall that high you usually dyno in mph. You likely wont show an decent graph in rpm possibly even locked.
If they convert to mph it may look alot cleaner.
The rpm read a little low on Keith’s dyno when we did my lightning. It makes peak around 5300 on my dynojet but only showed 4700 on his. Torque Has always been ~600 in my truck, and hp is about spot on at the time I dynod. If you didn’t lock the converter that left some on the table but it looks like it’s falling off hard up top. Have you put a wideband on it ? Or logged for spark advance ?
I do have a wide band and it was reading about 12.3 the whole pull spark ramps in from 27 to 31 degrees at 3400 and stays at 31 degrees for the remainder of the pull. do these seem like reasonable spark numbers? it has 10.25 compression
That is one of the most unusual dyno curves I have ever seen. It peaks way too early and falls off a cliff. Darth is right. Camshaft was not installed correctly and I also think you have some serious valvetrain issues. If I had a curve like that I would be checking pre load, pushrods, checking the valve springs etc. Something is not right.
When you say the cam is not installed correctly do you mean it is not in time? I will check my pre load today when i get home from work.
any other suggestions to check while i'm in the engine?
That spark advance is higher than I usually see but your compression is low, so the timing makes more sense.
I want to be very clear. That super high torque spike at 3500 that tails off with rpm is the converter flashing. You get torque multiplication by design. It was the 5400 rpm peak with fast fall off that made me suspect the cam.
I had a motor that did that same thing. Hit peak at 5600 and fell hard. The cam was off nine degrees.
That spark advance is higher than I usually see but your compression is low, so the timing makes more sense.
I want to be very clear. That super high torque spike at 3500 that tails off with rpm is the converter flashing. You get torque multiplication by design. It was the 5400 rpm peak with fast fall off that made me suspect the cam.
I had a motor that did that same thing. Hit peak at 5600 and fell hard. The cam was off nine degrees.
Well i pray that i'm not that far off, but i will go ahead and remove the front timing cover today. I guess i need to go ahead and purchase a degree wheel.
Before you do that .. see if they'll let you make a pull with the converter locked. Way cheaper to try that first. If it does better, you will not need to open it up
Before you do that .. see if they'll let you make a pull with the converter locked. Way cheaper to try that first. If it does better, you will not need to open it up
well i actually did this during a dyno day and it was cheaper the closest dyno to where i live is 30 minutes and they charge $400 to get on it and $30 a pull afterwards. So i'm avoiding dyno's now...Plus i already had to remove the intake to find an oil leak so its down right now.
I do have a wide band and it was reading about 12.3 the whole pull spark ramps in from 27 to 31 degrees at 3400 and stays at 31 degrees for the remainder of the pull. do these seem like reasonable spark numbers? it has 10.25 compression
That is one of the most unusual dyno curves I have ever seen. It peaks way too early and falls off a cliff. Darth is right. Camshaft was not installed correctly and I also think you have some serious valvetrain issues. If I had a curve like that I would be checking pre load, pushrods, checking the valve springs etc. Something is not right.
When you say the cam is not installed correctly do you mean it is not in time? I will check my pre load today when i get home from work.
any other suggestions to check while i'm in the engine?
Nothing else.
I would certainly check how the camshaft is installed first then check the rest.
The converter locked would be worth a shot too.
well i actually did this during a dyno day and it was cheaper the closest dyno to where i live is 30 minutes and they charge $400 to get on it and $30 a pull afterwards. So i'm avoiding dyno's now...Plus i already had to remove the intake to find an oil leak so its down right now.
That is RETARDED dyno pricing. Very typical for $65-$80 for three pulls baseline only, non-tuning. Once you start tuning it is usually either a flat fee or $100-$140 per hour
That is RETARDED dyno pricing. Very typical for $65-$80 for three pulls baseline only, non-tuning. Once you start tuning it is usually either a flat fee or $100-$140 per hour
well there is only 2 in town. and they are both stupid high, the next closes one is 3 hours away. I guess they think they have the market
another thing i forgot to mention is that he told me to hold the car at 2000 rpm so that he could set something ( i don't remember) I'm guessing a gear ratio. I never got to 2000 i was around the 2300 mark. Would that throw things off on the power curve?
update: I pulled the timing cover off of the motor last night to check the timing of the cam. Everything was in time as far as dots lining up. The only thing i noticed was that there was alot of slack in the timing chain. Could that cause the rpm to shift 1000 rpm?
I will be checking the valve train today after work.
update: I pulled the timing cover off of the motor last night to check the timing of the cam. Everything was in time as far as dots lining up. The only thing i noticed was that there was alot of slack in the timing chain. Could that cause the rpm to shift 1000 rpm?
I will be checking the valve train today after work.
If the camshaft is installed properly, and you have the tune and converter sorted out and it's still the same.
Then it would have to be something wrong in the valvetrain.
I had an issue once.
I was running a Lingenfelter 229/242 114 LSA camshaft once when my engine was a 6.0.
It made very good power however after 5000rpm the power just died off when this camshaft should have pulled to 6800rpm+
I found out later, those lobes on the Lingenfelters camshaft are Comp LSK which are brutal on the valve train and you need very strong springs to control them.
I just had average dual valve springs that were rated to .650 lift.
I also believe my valve train geometry was not right either but I could not confirm this. Maybe even the pushrods were not strong enough or the preload wans't right. Maybe even a combination of both.
I was dealing with a moron who was in the middle back then who I no longer use anymore.
He ended up not being able to sell his business because of his bad reputation, and then he burnt it down and made it look like it was an electrical fault with the wiring even though the building was only 5 years old.
06-11-2019, 09:22 PM
are these numbers reasonable 
