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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Had a shop swap out my black mamba cam for a small custom EPS cam 222/238 118 +4 .639"/.604 & retune (both dyno and street tune). The car also has PRC265 heads, Kooks LT's w/cats and Halltech intake.
This past Friday the first email from shop said the final numbers were 511whp and 484 wtq. Note this is on a DYNOJET, not a mustang dyno. They were then going to take it out for a street tune. Then I got another email about 45 mins later, that in a nutshell said the car isn't going to be ready for pickup as they saw something weird happen with the fuel trims and noticed some bucking and were suspecting a fueling issue. They asked if the tank was ever out of the car and if the fuel system was ever modified. I emailed the original owner and he replied that there were no mods to the fuel system.
This morning they said they will take it back out when it stops raining for more street tuning and he was going to check with the main guy to see if there were other things they were going to look at.
In terms of the numbers, I've seen other guys with almost the same or better numbers with only LT's and a tune. This car in addition to that has H/C (albeit a baby cam, but still)
On a side note he says "he saw some weird fueling stuff and experienced the bucking you may have been talking about." This comment took me back as I didn't mention anything other then normal stuff for a big cam, (mild bucking/surging below 1200rpm) and that the car ran perfectly, and that the new baby cam was a custom grind specifically to be very smooth and easy to drive. He ignored that email.
Get another email with "he saw something weird happen with the fuel trims and noticed some bucking so we wanted to make sure that there wasn’t another issue that you were seeing"
I don't know what he is talking about any issues that I mentioned. All I mentioned was how I needed a smaller cam for Long Island traffic because as we all know big cams can surge or buck below a certain rpm. It seems like they are trying to make it like there was an existing issue which worries me. I can say that I've driven the car 5x with the original black mamba cam, including the 4-hour trip to the shop and the car ran perfect, That included me getting on it several times as well as just cruising. All different types of driving. The only thing was, again, the mild surging/bucking if you go below a certain rpm as to be expected from a big cam.The car only has 10k miles on it and was meticulously maintained.
This new cam is obviously a baby cam and should be smooth as butter. And I assumed the numbers would be better on a dynojet. The temps were cool too (in the 60's).
Numbers aside the thing that caught my eye is the bucking. My cam is a bit bigger 22x/24x on a 118 lsa and it drives almost like stock. There is a problem here. As for numbers with PRC265cc heads, cam above, cat delete(stock manifolds still) and a Callaway intake made 536rwhp 485tq on an accurate dyno.
Hard to compare numbers from dyno to dyno. Just make sure all the issues are sorted out before you take delivery of the car. Test drive the car with someone from the shop before you leave. As long as it drives 100% how you want it, don't fuss too much about numbers. You could always throw it on a different dyno to compare.
Ive heard of lower numbers using PRC heads. Did they baseline the car before they took your old cam out?
Numbers aside the thing that caught my eye is the bucking. My cam is a bit bigger 22x/24x on a 118 lsa and it drives almost like stock. There is a problem here. As for numbers with PRC265cc heads, cam above, cat delete(stock manifolds still) and a Callaway intake made 536rwhp 485tq on an accurate dyno.
The thing is, there was NO problem when I had the car. As I said, mild surging/bucking below 1500rpm is totally normal with a big cam, which the black mamba cam I had was definitely a good sized cam.
Hard to compare numbers from dyno to dyno. Just make sure all the issues are sorted out before you take delivery of the car. Test drive the car with someone from the shop before you leave. As long as it drives 100% how you want it, don't fuss too much about numbers. You could always throw it on a different dyno to compare.
Ive heard of lower numbers using PRC heads. Did they baseline the car before they took your old cam out?
No, they didn't do a baseline with the car as it was when I dropped it off, but the previous owner recalled it being 570rwhp (he couldnt find the dyno sheet. It was tuned at Wong Performance in WA. I can tell you the 3rd gear pulls I did on the highway with a starting point of 70mph, were ridiculous...in a good way.
I've seen plenty of good dyno numbers with PRC heads.
The thing is, there was NO problem when I had the car. As I said, mild surging/bucking below 1500rwp is totally normal with a big cam, which the black mamba cam I had was definitely a good sized cam.
Could just mean more work to be done in the tune...let them get through the street tune and see if the "issues" persist.
The thing is, there was NO problem when I had the car. As I said, mild surging/bucking below 1500rpm is totally normal with a big cam, which the black mamba cam I had was definitely a good sized cam.
My only guess is the tune then, that cam should drive amazing compared to the black mamba. Only thing changed here other than the cam is the tune correct? My cam drives like butter and it's bigger than yours. What shop is doing the Tuning if you don't mind?
I have an EPS 224/236 (+4) .649/.649 cam and AHP lightly ported heads+lightly ported stock intake manifold. LG catted headers/stock exhaust. 505hp on a dynopac, which I thought was low... car drives as stock except for the slightest rock at idle (850). Zero surging/bucking/etc during normal driving. Performance seems adequate...
My only guess is the tune then, that cam should drive amazing compared to the black mamba. Only thing changed here other than the cam is the tune correct? My cam drives like butter and it's bigger than yours. What shop is doing the Tuning if you don't mind?
Correct, the only changed was the cam and the tune.
Although I also had them put in brand new GM rockers as I wanted to be rid of the rockers w/the comp trunions the previous owner did.
I have an EPS 224/236 (+4) .649/.649 cam and AHP lightly ported heads+lightly ported stock intake manifold. LG catted headers/stock exhaust. 505hp on a dynopac, which I thought was low... car drives as stock except for the slightest rock at idle (850). Zero surging/bucking/etc during normal driving. Performance seems adequate...
WOW, maybe these EPS cams just dyno super low for some reason? These numbers just don't make sense. I've seen plenty of examples of better numbers both HP and TQ with stock heads and cam!
Here's one right here. All this is, is ARH LT's w/cats, CAI & tune:
I still say something is wrong with the tune though. The car should not go from 570rwhp to 511rwhp from just the cam swap. The difference in the 2 cams shouldn't be that significant.
Agree with above, dynos vary... plus It's hard to judge the difference between the two cams since their wasn't a baseline dyno before your swap, the owner before you numbers are a good reference but you're not comparing apples to apples since both runs were not done on the same dyno. You are most likely right, there is a tune issue if it still bucking on you. Hopefully when the tuner street tunes it will resolve this, good luck sounds like a nice setup hope it works out.
I still say something is wrong with the tune though. The car should not go from 570rwhp to 511rwhp from just the cam swap. The difference in the 2 cams shouldn't be that significant.
From a big cam to a baby cam...I would expect a decent drop. Having said that, I would have guessed you'd be in a realistic 525hp range. I also think there's more work to be done in the tune based on your comments of drivability issues with the new cam.
I recently did a head and intake swap. Previous shop that installed and tuned for my previous set up was Lethal Racing. Their dyno showed it was 572/541. Had baseline with this exact setup on a Mustang dyno. Showed 480. I know Mustangs read lower, but I went from 572 to 480. Dynos vary and some shops calibrate their dynes differently. This was a full bolt ons with smallish cam.
Yeah I'm just clinging to the hope that they are good tuners and get the tune dialed in. It's a bit nerve racking dropping your baby off to virtual strangers and then having "issues" come up that don't seem to make sense.
Also, I asked for pics of the build. Right on google reviews someone from 4 weeks ago said they surprised them by updating with pics along the way of the build. Here I specifically asked for that and no dice. Also asked for some video of the street tune, was denied that too. They said they took video of the dyno, and this past Friday they said they'd post it in a few minutes. Still haven't seen that either. No response yet to my emails from yesterday morning either.
I'm having the same EPS 222/238 118+4 cam installed this week with AHP heads and a halltech mf103 as the only mods. I will post my numbers once it is finished so you can compare.
06-05-2017, 06:34 PM
Lowest numbers ever for a H/C/I/LT C6Z?
