Les-10

Had mods done a little over a year ago (08Z w/25K, already had Halltech MF-103).
1) Heads refurbished w/SS REV exhausts & bronze guides, BTR dual springs, milled .030" (no porting)
2) Installed Katech Torquer 110 with new lifters, new shorter (7.750") pushrods
3) Installed 1-7/8" ARH's w/catted x-pipe
4) Timing was reported to be 19 degrees at WOT

Happy with WOT performance as well as the increased torque but very disillusioned with the surging & bucking. The 110 has a good reputation wrt street manners but mine just seems to be harsher and choppier than everyone else's. Ive been told that it's the nature of cammed cars, but I've been driving cammed cars for 45 of my 65 years (just not the fuel injected LS variety).

Anyway, I recently saw post comments where AFR's of high 12's were considered high or lean. When I looked at my sheet, I saw 13.59. Am I not reading or understanding correctly? So I thought I would post my sheet and ask for comments.

Do I need a re-tune or is the relative high DCR of the 110 combined with the .030" head milling playing havoc with my setup?

Pinski 1

I have the identical set up as you do and I am getting more bucking and surging between 1100 & 2000 RPM's than I expected in the lower gears (I expected it in the higher gears). But, I didnt have anything to compare it with so I dont know if its normal or not. Tuner said it was normal.

edmundu

Bucking in the lower gears is normal. Particularly at low load/throttle. In higher gears, it should be smooth from 13-1400 on up, as the loads are high enough.

Some tuner's choose NOT to tune the SD, and many disable it completely. If you tune in SD, a lot of the bucking, surging goes away.

Pinski 1

Whats SD mean ?

Z.06

My 2008 Z06 has a Halltech 103, ported OEM intake manifold, OEM heads (thanks GM), no head cutting, Comp Cams 228/248 on 114 deg with 8 degrees overlap. Lift at valves is 0.623/ 0.652 inches on PSI dual valve springs. The exhaust manifolds and pipes are OEM with muffler mod. It has been tuned three times, first by Lethal Racing Lafayette, then by England Green, and finally by 510 Racing (to correct the problems created by EG tune). The LR tune, perhaps in combination with Lingenfelter CAI which they also installed gave horrible surge at highway speeds. The car was damn near undriveable. This was tamed a bit by a SD tune, but road mileage was terrible. They recommended replacing the Lingenfelter CAI with a Halltech 107, which I installed and had tuned by EG. Only problem was that 25 hp disappeared, and EG could not find it. Apparently they could keep my $550 though. No refund. I paid another $500 to 510 Racing to do the job that Lethal and EG could not do. I am happy with the result. 510 Racing did get rid of the highway surge problems, they found the 25 hp that EG had lost, they improved fuel mileage, and they minimized the cowl shake that resulted from both the LR and the EG tunes.

Regarding your situation, limiting timing to 19 degrees sound like an issue to me. Is this all caused by your CR? I have at least 24 or 25 without retard issues. My car w/o tubular headers is producing that same torque as your with tubular headers, and within 20 hp of your peak.

I would think you may need to find a smarter tuner. Once you find him, your drivability will probably improve as well.

Vito.A

SD= speed density
A talented tuner can smooth some of that surging/bucking. You can also drive the car in a lower gear and avoid it. As someone else said, it's usually only when you let off the throttle, not when adding throttle.


The Torquer 110 raises dynamic compression ratio, so you really need quality fuel or you have to pull timing.
The newer Torquer 110 uses a 110 lobe separation angle with a +004 to smooth it a bit. If you even want smoother low RPM operation, they recommend the Torquer 116 with a 116 lobe separation angle.


Quote from Jason: "By most people's standards for doing a camshaft it's (110) mild, but the 116 is even milder still"

Les-10

Am I OK with my A/F ratio numbers listed on chart?

edmundu

Yeah AFR's look fine, considering they are likely tail pipe #'s. So with a catted setup, plus being at the exhaust exit, they will read a bit leaner than actual.

The dotted red line is 13:1, and you were only above it around 4-4.5k...At the tailpipe. Which means in the cylinders, you're much closer to the widely used 12.5:1

db2xpert

Have similar setup heads milled, with torquer 110 cam. Had low rpm surging from original tuner... could not fix it.

Found another tuner, and now NO low speed surge.
It probably CAN be tuned out, or pretty close to it.

Unreal

AFR is a bit on the lean side, but that is just WOT, not part throttle and would have no effect on bucking/surging. The 13.59 AFR is just at that one point where the vertical line is at the start of the graph. Nothing to be concerned about.

A torquer 110 is a very mild cam overall. It should drive really well.

Les-10

Thanks for addressing the AFR, that's some relief. I have a friend with the Torquer 116 (with an A&A) & another with a fairly aggressive 231/238 113 lsa cam & ARH's in a LS3. Both the other cars drive like absolute dreams (very, very little surge) & their AFR numbers are lower. Although I don't have a direct comparison (apples to apples), most of what I read & hear makes me think my 110 should have better driveability as well. Gonna be looking for a local tuner soon...

MarkC

Les, Undy can help you with this problem. He will probably way in or just PM him.

Frans96ss

Give us a call. We can get the tune straightened out for you.

Red Mud

I also experienced surging /bucking and my tuner switched to a speed density tune. End of problem.
CAI turbulence maybe? I have the Torquer 110 and there is only slight surging now at low rpm.

Les-10

Any change in horsepower/torque numbers or gas mileage?

Red Mud

Ended up with 528/488 on a mustang dyno.
I believe it gained 12 hp if i remember correctly over the original tune.
Mileage did not change much, but drivability did. Alot smoother than before.

Les-10

Thanks Mark! On your recommendation I contacted him and he was most helpful.

MarkC

I hope it all works out to your satisfaction. Also, I hope to see you at Landston this summer.