RedRocketZ28

iTrader: (19)

Alright guys, when my car had just a lid and long tubes it ran a 13.3 @ 109 with a bad 60'. Regardless of the 60' I am worried about the mph. Fast forward to a couple of weeks ago. Have had a custom cam spec'd by Patrick G installed for over a year and a half now and just got to the the track with the car a couple of weeks ago. The car was tuned by a guy locally. He had trouble getting it to idle decent, we had it on the dyno and the a/f was supposedly fine as well. Anyway it put down 345/335 on a SuperFlo dyno. The graph doesn't look great to me either.



So back to the track I went. Ran a 13.1 @ 109 with a 2.1 60'. This was with the custom cam which specs .231/.232 .612/.592 111+4 and had an LS6 intake added at the time of the swap. Car doesn't seem to have any torque down low at all. Wont break the tires loose from a roll until around 4k. Seems to pull strong up top though and pulls all the way to redline.

Thinking the cam might be retarded and off a tooth I took it apart last weekend. Wanted to install a new oil pump and timing chain since it is still on the stock ones anyway. Well three of my buddies confirmed the cam is dot to dot. Patrick said this cam should be at a minimum a 50 rwhp cam. Other guys with similar cams seem to make over 400 rwhp too. I am still on the stock heads but still should be close to 400 rwhp and am not even close obviously. So to the initial question. Is it possible to be losing 5-6 mph from a bad tune? Haven't had a chance to get the car completely back together since I left for vacation the weekend I tore it down. Once I get back I am planning on getting it back together and taking it to a shop here in the midwest to have someone get a different tune on it. Sorry for the long post all. All suggestions and help and greatly appreciated. Thanks all!

RedRocketZ28

iTrader: (19)

Anyone? Just want some input guys.

Pharcyde50

iTrader: (11)

Something is wrong I used to trap at 112mph with just bolt on's. I'd say the tune is off that cam shouldn't be that hard to tune at idle. What were the wideband readings on the dyno? What are you using for valve springs?

RedRocketZ28

iTrader: (19)

Hey thanks for the reply. Yeah I know something is wrong. Don't remember what the exact wideband readings were on the dyno but the a/f ratio was good according to the wideband though. The tune has to be messed up though. The #7 cylinder plug was pretty burnt up as well. Running Patriot dual springs as well.

Going to get it put back together and take it somewhere to get tuned. Should run a lot harder than it does obviously. Hope there is nothing wrong with the motor. It's only got 34k on it too.

RedRocketZ28

iTrader: (19)

Any other opinions?

AutomagicLS1

iTrader: (18)

Buy a wideband and find out what the afr is yourself. It could be lean. I lost a motor b/c of this so dont become a victim

DrkPhx

iTrader: (15)

What rpm are you shifting at and what is the AFR at WOT? I don't see it on the dyno sheet. What track are going to?

ringram

Maybe a smaller duration would suit your app better and give you back some low end torque. Speak to Pat maybe you old and new requirements dont match.

RedRocketZ28

iTrader: (19)

I go to a track here in Iowa. Cars usually run good around here. Shifting at around 6200 RPM. Not sure what the A/F is at WOT. Last time it was hooked up to a wideband was on the dyno, and the guy tuning was the same guy who started tuning it. I remember the A/F being right on then, but maybe the wideband wasn't any good, I don't know.

Patrick custom spec'd the cam for what I wanted. Told him I was staying on the stock heads and wanted around 400 rwhp. This cam should make power and it's not for some reason. Have been told by others around here to get a good tune on it and see what happens.

mostmint

You need to check the basics to make sure something obvious is not causing this:
1) Does the throttle open all the way?
2) Is your compression good in all 8 cylinders?
3) Is the cam really what you paid for - I mean are the lift, duration, overlap consistent between cylinders and matching your spec?
4) Is there enough fuel pressure/flow/injectors capable of supporting the extra fuel needs. This is why you need to see the AFR.

Sounds like you lost some bottom end but can't capitalize on the top end.

It is .2 faster so how much HP did you gain so far - any?

01FbTaWs6

iTrader: (12)

I can answer some of these questions for him, as I helped initially with the install. The cam is dead on what he ordered, verified by the cam doctor at thunder racing. His valve springs are golden. The cam should suite his needs perfect. He does need to shift higher, closer to the 6500-6600 range IMHO. The injectors should be fine since he is cam only/bolt ons. Im thinking the tune was very lean, very very lean. He was supposed to go to a tuner here in the midwest today I believe. Ill have him post up what they found.

mostmint

You could be right on that. I am still an infant with the tuner and am "track tuning" as opposed to dyno tuning. But I put in a tune last night and leaned out the top end in the power enrichment mode and knocked about 2 mph off my 1/4 mile time. It's not hard to do.

Could also be timing too retarded, maybe knock sensor cutting back on the timing?

RedRocketZ28

iTrader: (19)

Well had the car to House of Boost today. It put down 386/384 on their dynocom dyno. Seems to run a lot better than before. I was pretty happy with the #'s. Need to get it to the track to see what it runs now.

RedRocketZ28

iTrader: (19)

Here's the graph. Kind of hard to see, had to take the pic with my cell phone.