What's going on here? Down on power...
What's going on here? Down on power... So a few weeks ago I added a custom cam 231/232 .612/.592 111+4 and LS6 intake to my otherwise bolt on car with 16k on it. Well before the cam and intake I ran a 13.3 @ 109 with horrid 60' and babying it out of the hole due to bad wheel hop. The car felt pretty strong after the headers.
So fast forward...
Installed cam, drove it untuned for a week or so but never got on it and did not drive it every day. Had someone start tuning on it recently and found it was pig rich, to be expected though I understand. Anyway, after some more tuning the AFR is right around 12.4. Still really rich I know. But, last night I raced my buddies full exhaust car from a 45 mph roll and only beat him by half a car. He got the hit and I passed him while still in 2nd but held that lead and barely inched on him up until 110 or so. What could possibly be wrong with my car? The cam is installed dot to dot, we checked it several times. Could it be something in the tune holding back that much power? Is my car just a turd? Did I mess something up driving on it untuned? The car runs great so it has me baffled. What do you guys think? Thanks.
So fast forward...
Installed cam, drove it untuned for a week or so but never got on it and did not drive it every day. Had someone start tuning on it recently and found it was pig rich, to be expected though I understand. Anyway, after some more tuning the AFR is right around 12.4. Still really rich I know. But, last night I raced my buddies full exhaust car from a 45 mph roll and only beat him by half a car. He got the hit and I passed him while still in 2nd but held that lead and barely inched on him up until 110 or so. What could possibly be wrong with my car? The cam is installed dot to dot, we checked it several times. Could it be something in the tune holding back that much power? Is my car just a turd? Did I mess something up driving on it untuned? The car runs great so it has me baffled. What do you guys think? Thanks.
TECH Apprentice
Joined: Apr 2005
Posts: 319
Likes: 1
From: North Carolina
My cam and your cam seem pretty close. I put 100 miles on mine to break the cam in and I changed the oil. Mine too was disgustingly rich, the car felt like I hadn't done a thing to it.
I would say you still may be too rich and its just falling on its face. A new intake, headers and the cam throw the air pressures in the engine off. (lot more flow). Mine is being tuned as we speak, so I will have more info when I get it back tommorrow.
I don't think your car is a turd, but i think the tune needs to be gone through with a fine toothed comb and it will be right. What you did is a lot of changes from a stock engine.
I would say you still may be too rich and its just falling on its face. A new intake, headers and the cam throw the air pressures in the engine off. (lot more flow). Mine is being tuned as we speak, so I will have more info when I get it back tommorrow.
I don't think your car is a turd, but i think the tune needs to be gone through with a fine toothed comb and it will be right. What you did is a lot of changes from a stock engine.
I had the headers before the cam though. It feels exactly the same to me and shows that by pulling on a bolt on car by 1/2 car. I don't know man, I hope it is in the tune.
There is not really enough information here for anyone to accurately pinpoint the issue.
-Previous track runs did not show much improvemnt over stock
-No before/after dyno numbers
-Street comparision to a modified car gives little indication (but agree that you should walk a full exhaust car)
The tune would seem like the first logical place to look. What timing are you running at WOT? 12.4 AFR isn't horrible, but may not be what your car wants. Did you get a dyno tune?
-Previous track runs did not show much improvemnt over stock
-No before/after dyno numbers
-Street comparision to a modified car gives little indication (but agree that you should walk a full exhaust car)
The tune would seem like the first logical place to look. What timing are you running at WOT? 12.4 AFR isn't horrible, but may not be what your car wants. Did you get a dyno tune?
Thanks for the response Hammertime. I agree there is not much information to go on, but it's all I have right now. My previous track times are bad, but the trap speed is on par to what other bolt on cars run. My buddy ran a 12.9 @ 110 with bolt ons and that was an LS6 intake car that he tuned with HPTuners.
The car has not been dyno tuned. We have been tuning on the street. The timing is the first thing that I thought of. I am not sure what it is set at. I will ask that today. We are supposed to do more tuning on it today sometime.
I know this isn't the easiest thing to advise on, but I have no before or after dyno numbers. Still, like you said, I should have no problem walking away from a full exhaust car. Something isn't right and it upsets me, haha. Makes me feel like the cam swap was a waste of time and money and all I got out of it was a nasty lope.
The car has not been dyno tuned. We have been tuning on the street. The timing is the first thing that I thought of. I am not sure what it is set at. I will ask that today. We are supposed to do more tuning on it today sometime.
I know this isn't the easiest thing to advise on, but I have no before or after dyno numbers. Still, like you said, I should have no problem walking away from a full exhaust car. Something isn't right and it upsets me, haha. Makes me feel like the cam swap was a waste of time and money and all I got out of it was a nasty lope.
I do need to get it to a dyno and look at the power curve. It doesn't really feel like it falls on it's face though. I know it is possible that it is off a tooth, but just isn't likely since we checked it a couple of times. Obviously that could cause a drop in power and still run okay right? I don't know. This is frustrating because I know the car should have more power.
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The A/F is now at 13.0 at WOT. The guy tuning the car knows what he is doing. He tuned my buddies 408 Katech Motored car as well as his own GTO. He has been doing it for a while. My car starts fine, idles fine, drives fine, but there just isn't the power there. The car only has 17k miles on it so the block is nice and fresh. I have an appointment to get it on a dyno here locally to see what the graph looks like. That will hopefully tell me what is going on. Only problem is that the guys who own the shop deal with Mustangs. It's the only dyno close though. The guy tuning it for me is going with me as well so he will be able to mess with things on the dyno. If all else fails I will be tearing back into the motor.
Quoted from the first thread I found on this subject...This is pretty much what I've always been told by the tuners I've talked to....
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
I have a 12:1 370, with 9.0 DCR, 224/222 117 cam and best street power is made on 12.5>12.6 AFR (WOT)
Mines at 12.8 across the board at WOT......What i think and the stuff that i read seem to say 12.8-12.9-12.7 is about what u wanna be....no 13.0 isnt way lean but i know i dont wanna see my car at 13.0 at WOT, just my preference tho.
What does yours run?
I was running 12.70's at 106mph with the old fuddle 3400 with a DA of 5500....swapped to a vig 3600 and lookin for 12.50's....then a 11.80 on the bottle.....WIsh i was closer to sea level id be in the 11's without the bottle...lol...stock A4 ls1 run 13.9-14.3 around here.
I was running 12.70's at 106mph with the old fuddle 3400 with a DA of 5500....swapped to a vig 3600 and lookin for 12.50's....then a 11.80 on the bottle.....WIsh i was closer to sea level id be in the 11's without the bottle...lol...stock A4 ls1 run 13.9-14.3 around here.