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[Z06] ZO6 LS7 does not run like I think it should HELP
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
With the 1st cam 433 RWHP
With the 2nd cam 393 RWHP
That's obviously really low for an LS7 installed in a Z06. Stock Z's make ~450 RWHP on average. I guess the question is: how much power is that TH400 sucking up, and how much is that non-lock up converter affecting the dyno numbers?
I helped a buddy build a supercharged LS1 that went into his '70 Chevelle. It was an almost identical clone of an engine that I had in a '67 Camaro at the time. Same cubic inches, same cam, same heads. His had a bigger/more efficient blower, though, making about 3 psi more. Both cars on 91 octane + meth.
Even through a TH350 with a 3000 stall, he made 30 RWHP more than my car did with a modern T56 6-speed manual. Both cars had Ford 9" rear ends. Both tuned by the same guy and on the same dyno.
The point of my story? I don't think your drivetrain is sucking up THAT much power. I know a TH400 is worse than a TH350 when it comes to power consumption, but still. Your motor should be a solid 530 RWHP through a manual. For it to make less than 400 RWHP, I'm thinking something is off.
Anyone else think it looks like a restriction the way it bends back like that?
Yes, I'd fab up something better flowing than that which could pull ambient air from the front if at all possible. I doubt this is the cause for missing a ton of HP though.
Originally Posted by bada
With the 1st cam 433 RWHP
With the 2nd cam 393 RWHP
That's pretty darn low for a cammed LS7. I'd almost say try another shop.
First off, if the motor is only putting out ~400RWHP with an auto and given that you have an aerodynamic brick I'd say 127MPH is about right. Was the 127MPH with 433RWHP or 393?
The air intake is likely causing about a 10-15HP drop could be more...you'd just have to straighten it out on the dyno and see...you might be surprised!
I'd really like to see what your logs look like on the dyno (A/F, timing, KR, etc) along with air temps...can you post these? Your motor seems to be way underperforming and before changing anything the base power level needs to come up.
First off, if the motor is only putting out ~400RWHP with an auto and given that you have an aerodynamic brick I'd say 127MPH is about right. Was the 127MPH with 433RWHP or 393?
The air intake is likely causing about a 10-15HP drop could be more...you'd just have to straighten it out on the dyno and see...you might be surprised!
I'd really like to see what your logs look like on the dyno (A/F, timing, KR, etc) along with air temps...can you post these? Your motor seems to be way underperforming and before changing anything the base power level needs to come up.
The 127 mph was with the 433HP. I do not have the logs. The tuner has that info. But I might can get a copy.
FYI Ive lost 5mph with flowmasters vs spiral flow mufflers on a H/C ls1 fbody.. same night same track put flowmasters on straight off the trailer and went 5mph slower than the previous weekend. Went back to trailer swapped back to spiral flows, went back to staging lanes and picked up the 5mph we lost... Not saying thats your issue as you are WAY down on power but that could be part of the problem.. Can you send me your tune? Even with your aero issues I would expect around 132-134 at your weight.
high stall converter will kill dyno numbers. Doesn't mean the power isn't there. a dyno pull with the converter locked would have given a better representation though. Looser converter = lower numbers.
high stall converter will kill dyno numbers. Doesn't mean the power isn't there. a dyno pull with the converter locked would have given a better representation though.
His MPH backs it up though? @ 2600lbs mid 130's should be the norm.
Maybe this will post. I broke a shock on this run. So I backed out on down track. The pass would probably, have been another 10.00. So this will give you guys and idea, on how the truck runs. This is the stock cam.
Maybe this will post. I broke a shock on this run. So I backed out on down track. The pass would probably, have been another 10.00. So this will give you guys and idea, on how the truck runs. This is the stock cam
It's definitely the Aero killing you...between the front fenders sucking air under them and the brick wall grill and windshield it's amazing that you run as fast as you do!
bada, this will put your mind to ease once and for all to show you how much the Aero is killing you....take a look at the simulation below....I took my 1988 Monte Carlo SS and backfitted the actual track MPH into Quarter Mile Jr to reflect the MPH demonstrated at the track when the motor was all stock with headers and it was only down about 27 RWHP from what it did on the chassis dyno (~460RWHP demonstrated vs 487RWHP on the chassis dyno). My car had 4.10's and a T56. I used this same data and swapped your transmission/convertor, gears, weight and aero date (the aero was just a guess using a van as the aero value) and you can see that your MPH is likely where it needs to be compared to my car....my Monte ran an 11.52 @ 121.66 MPH and what's important here is the MPH, not the ET.
high stall converter will kill dyno numbers. Doesn't mean the power isn't there. a dyno pull with the converter locked would have given a better representation though. Looser converter = lower numbers.
While that's true, I really don't think it's sucking up that much power on the dyno. See my post earlier in the thread about the two cars I built/helped build. The one with the 3200 stall (no lock-up) and TH350 didn't seem to suffer too much compared to the T56 car. Granted, the TH350 car had a TVS2300 with a few more psi vs. an MP122 on the T56 car, but it still made 30 RWHP more.
The OP's car looks to be missing almost 150 RWHP. I don't see that just being from the trans/converter setup.
What was the track density altitude on these runs? What rear tire are you using?
I really don't think you are that far off. The dyno numbers are low, but like the others have said its because of the converter. These trucks are poor race cars as the weight distribution is backward and the aero is bad. You might pick up a tenth with a good Powerglide.
FYI Ive lost 5mph with flowmasters vs spiral flow mufflers on a H/C ls1 fbody.. same night same track put flowmasters on straight off the trailer and went 5mph slower than the previous weekend. Went back to trailer swapped back to spiral flows, went back to staging lanes and picked up the 5mph we lost... Not saying thats your issue as you are WAY down on power but that could be part of the problem.. Can you send me your tune? Even with your aero issues I would expect around 132-134 at your weight.
What are spiral flows. any specs Or web site for them? And I do not have the tune. The shop that tuned the truck has it.
What was the track density altitude on these runs? What rear tire are you using?
I really don't think you are that far off. The dyno numbers are low, but like the others have said its because of the converter. These trucks are poor race cars as the weight distribution is backward and the aero is bad. You might pick up a tenth with a good Powerglide.
Slowed down with a glide. I tried one. And this is the 3rd converter. And it is also the tightest one. So my dyno #s should have gone up not down. And my weight distribution when scaled, was 54% rear & 46% on the front. Now the aero is another story. I am sure it sucks.
Last edited by bada; 11-29-2014 at 10:35 PM.
Reason: .
11-20-2014, 10:00 PM
