scottss

Well, my car is finally finished. Installed the Lethal Cam w/supporting mods...Unbelievable power and sound...

but...

I am pretty sure this is all tune related ~ the cam is very, very nice...I may be just a bit sensitive.

I am not sure how much of the bucking and surging is too much. Just cruising in 5th and 6th gear @1500-1600 the car starts to buck like crazy...I totally was expecting that (was hoping for anywhere from 1000-1200rpms tho). Here it the thing, when in gear, any gear, when you let off of the gas a tiny bit, the car starts bucking very bad. Also, when cruising at over 1500-1600rpms, the car has a slight, very slight surge to it...kinda like the MAF is dirty or something. Forgive me for the "beginner" questions. This is my first true big cam car...I come from FI, so do I need to get used to this?

I know that Randy and Shawn at Ragin Racing would definately dail it in better...but if what I am feeling is somewhat normal...then I don't think that I would need to ship my Z to them...may do it anyway, lol.

Thanks in advance!

Scott

Mods:
Lethal Cam
Kooks 1 7/8, catted
Callaway Honker
Trunion Kit
Corsa duals

520/470 sae
533/479 std

Geared

i dont know much about big cam stuff, so take this with caution....

it may be lack of air on the intake side....the honker, your stock tb, and stock intake manifold may not be providing enough air at low rpms to make your new cam setup happy....

who tuned? what was afr

Unreal

Should be better than that. My cam is bigger and it takes effort to get it to surge or buck.

scottss

That makes very good sense...I have debated on a NW TB and a FAST...or porting of the stock stuff. But before I did that, I wanted to see what a cam only setup is like.

Dynospeed in Memphis, TN tuned it...I am not sure of the afr...

I do know that "cam tuning" is somewhat of an art-form. I love the new power but I can see that the tuning part may need to be adjusted a bit.

Buddy A

And if you put a FAST on or port your OEM manifold and TB. You would need a retune anyway. Look for a fresh set of eyes to look at the tune. If you look on you tube, there are videos of Shawn driving a Lethal cammed car that seemed to drive very well. I would suggest calling Shawn. He should be able to help.

scottss

Thanks Buddy! I will check into that...

I have seen that Lethal driveability video...car seems to drive just fine...seems that RR would be the best choice to look at my car due to me having their cam.........

GaryZ06

It's your tuning.My Lethal Z06 has very little bucking or surging.I can be in 6th gear on the highway setting the cruise control at 60-70 mph and there is no surging or bucking at all.

DSteck

100% tuning related. Those are low numbers for a Lethal Z cam as well. My QM600 setup had almost zero bucking, and I could even take my foot off the gas in 1st gear and let it pull itself through a parking lot. Then again, I had a lot of time invested in tuning my own car. Either way, a good tuner can clear that up very easy. I've rarely had mild cams like that give me issues that couldn't be fixed with some time spent cleaning it up.

scottss

The tuner I have is well versed in FI and not as much for a cammed car (especially a 427). I do plan on out-sourcing to clean up the tune...eventually.

Would the addition of a FAST 102 and a NW TB (or ported stock intake/tb) help with the airflow for tuning purposes and driveability?

Thanks guys!

Scott

0MR Z

Scott,

I have dialed in many Lethal Cams and what you are describing is not normal. It can definately be cleaned up a lot. We have many satisfied customers with the Lethal cam. It does have some surege to it under 1500 rpms, but not to the extent you describe. Usually on a decel it is no bad at all. Give us a call if you need help.

Shawn
337-354-9970

DSteck

FI is a cake walk in comparison to cam tuning.

A FAST 102 and NW 102 won't help you. If your tuner couldn't get the car to drive clean with a stock throttle body, then chances are the NW102 would totally mess that tuner up.

htvette

I have the same problem with a custom Comp cam 238/254/113. Is the Lethal cam bigger than mine? Thanks.

the_teapot

I'd check in with Shawn and Randy at Ragin Racin. My lethal Z runs super smooth - no issues at highway cruising speeds in 6th or upon deceleration.

FNQWK

my lethal z runs great. no probs

TORQJNKY

Your about 7 hours driving distance from Ragin Racin based on your sig location. May be worth a trip down to Cajun country to have Shawn do his voodo.

Randy@RaginRacin

Scott come see me!! I will get you fixed up. Lethal does have some surge at lower rpm's but not near as bad as you are describing.


Thanks

Randy
337/278/8397

Unreal

Same here. I can let my car just put around in 1-3rd gear no gas. In 4-6th it will get a bit unhappy if I'm zero throttle at 1000-1200 RPMs, but at the same time, like DSteck I have a lot of time invested in tuning my own car. I must say that my larger cam drives better than my friend's lethal cammed car. Then again we put about an hour into his driveability tuning and I have 30+.

VetteVinnie

It's all in the tuning. My lethal has exceptional drivability after Shawn at Ragin' Racin' tuned it. And I'm running a stage IV with higher compression. A local tuner tried to get it dialed in before I finally took the car to Louisiana, but it bucked and surged like crazy. 6th was useless on the highway. Now I can cruise in 5th or 6th even down to 1000-1100 rpm with no buck or surge on the highway.

That said, it does have some very minor surging in the lower gears below 1500rpm and will buck ever so slightly on occasion, but I'm sure that could get tuned out also if I really wanted to be **** about it. I don't cruise in the lower gears anyway and am usually running between 1500-2000 RPM (or higher ) on the streets until I hit 5th.

Side note, there is a resonant frequency at around 800 RPM idle that will really rock the car back and forth. Shawn tuned that out once before, but it came back after the latest tune adjustment (when I changed air intakes from the Vararam to the Callaway). I'll be taking it back to Shawn and Randy for some minor adjustments after I get the clutch swapped out (which I'm mostly doing myself with help from more experienced hands). Time to get my hands dirty.

scottss

100% agree...it is now on my "to do" list!

JWell

I bet it sounds like a beast, I would like to hear that thing