TREX Cam Need Help Please!
12-17-2010, 07:12 PM
#21
Bucking below 2K is about right for a 240+ duration cam on a stock geared Corvette. A lot of internet fan boys of these huge cams will tell you "mine drives great" but that's mainly because they're either delusional out of being excited just to have a cam in their car or they just don't know any better.
It's hard to say how much better a different tuner can make it drive since I can't see your tune, but I can tell you that 240+ degrees of duration on stock gearing is going to generate some buck/surge in the low rpm's regardless of who's tuning it.
One other possible thing is they could have not scaled the injectors properly, which will effect driveability as well. If the injectors are scaled wrong, it'll throw off the trims and WOT fueling. I've seen shops monkey **** their way around it by manipulating other tables to get their desired A/F, but it causes bad gas mileage/driveability.
It's hard to say how much better a different tuner can make it drive since I can't see your tune, but I can tell you that 240+ degrees of duration on stock gearing is going to generate some buck/surge in the low rpm's regardless of who's tuning it.
One other possible thing is they could have not scaled the injectors properly, which will effect driveability as well. If the injectors are scaled wrong, it'll throw off the trims and WOT fueling. I've seen shops monkey **** their way around it by manipulating other tables to get their desired A/F, but it causes bad gas mileage/driveability.
12-17-2010, 07:25 PM
#23
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3.90s are better than stock but that's low imho for running a t rex,I run 4.10s in my ms4 and in the process of putting in 4.30s,damien is right though,my car does drive well but had some bucking ,surging on stock gears it was real light but it was there,the 4.10s made the cam,4.30s my car should fly,big cams make all there power up top,higher gears will help you keep it in the power range,can I ask you why you went with the t rex?
12-17-2010, 07:49 PM
#24
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I am taking it back up to the shop that originally tuned it and will not take it back till everything is fixed.
12-17-2010, 09:16 PM
#25
The gear just keeps your rpms up a lil bit more in the 15 to 20mph range where the bucking is at,honest if you drove my car you would not guess there is a ms4 in it,I would put money on it,I have a lot of money spent on the dyno and the guy that tuned my car knows his crap,he was even shocked on how well it was on the street,bigger isn't better we all know that but a big cam setup right is hard to beat,I think you will be happy notraction when ya get the bugs worked out,and good choice in cam for highway runs,the t rex pulls very hard on top,its all in how its setup and tuned,I had no problems driving my car 14 hours home from north carolina,
12-17-2010, 09:25 PM
#26
My and my buddy just went out to log it. Died a lot and just would not run for crap, the fuel trim is -31% for both banks on the short termside.
And the maf is not reading to well so I am gonna clean it up and see if that helps.
Well my dumbass cannot seem to figure out how to upload on of the logs we did. Using excel to look at it. If someone could chime in to help me upload it correctly that would be great.
And the maf is not reading to well so I am gonna clean it up and see if that helps.
Well my dumbass cannot seem to figure out how to upload on of the logs we did. Using excel to look at it. If someone could chime in to help me upload it correctly that would be great.
12-17-2010, 09:32 PM
#27
Barney I agree with ya,a lot of people get caught up in (I can make 430 with just a cam)and that is such a bad move,I picked the cam that would most help me with my goals,and I'm happy with the ms4,I don't know how other guys rides drive but I didn't drop that much money on a tune for giggles,and as for the gears when those where put in we made a few lil adjustments on the tune so maybe that's where I saw most the improvments in lower rpms,but I still feel the gears helped more than a few lil adjustments,
12-17-2010, 09:35 PM
#28
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ok you either have a o2 issue, or your tune is messed up.... you can make a trex cam idle and drive decent, but surging below 2k is normal.... dont expect it to drive perfect... also every trex cam car i have done idles around 70-75kpa, your tuner likely either A) has it idling too low B) not enough timing at idle or c) both.... i cant accurately tell you whats going on because i cant see the tune/car
12-17-2010, 10:09 PM
#29
Ok thanks Ryne I will tell him this tommrow. I dont know if you remember me or not but I had my car in your shop last spring when I was in the Marines and stationed out in 29 palms it was a 02 Black Z06 and was getting a new CV Axle. Thanks for the help and fixing my car at a great price and you did a awesome job. I am always sending guys still in the military your way with LSX.
12-17-2010, 10:11 PM
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