05tbh

I have a 08 LS3 A6 (3.15 gears) & recently had a 224-230, .623/.623, 115+2 cam installed by a very reputable tuner in the N. Texas area. Also, they installed a 100hp shot of nitrous. They have done all my work & have always provided the best customer svc & workmanship. I would not hesitate to use them again. However, they told me their 224 cam would provide good power & still be very drivable with no bucking, surging or overall idling issues. Long story short, they set the idle at 725rpm and it bucked, surged and idled so rough that I had to take it back & have the idle raised to 775rpm to address the issues. Keep in mind, they specialize in corvettes & really know their stuff. I guess I'm frustrated because I was told this cam would be very streetable which I believed since I've read many things on the forum about how tame the 224 cam runs. I am here to tell you, mine idles like a top fuel dragster.

Here are some of the issues: (1) Tuner said I would have to use paddle shifters in some situations to keep the RPMs up since the A6 likes to shift all the way to 5th gear even at low cruising speeds which would cause the car to run at 1200-1400rpm & would promote bucking, etc. I was never told this before the cam install & now I’m required to use the paddle shifters most of the time around town because it’s the only way to keep the motor above 1800rpm to minimize bucking/surging. (2) when coming to a near stop, the car will buck fairly hard as if it doesn’t want to stop (3) when cruising at a consistent speed (under 2000rpm) you can feel a very slight surging at times (4) car will sometimes idle fairly smooth at a stop and sometimes it will begin shaking the car fairly hard (tuner says it’s the O2 sensor testing/adjusting). (5) when a/c is turned on it bumps the idle to 800rpm which smoothes the idle, but increases the brake pressure needed to stop the car. (5) Tuner doesn’t tune VE tables because he said that limits your ability to drive the car in other altitudes, etc.

To address the issues they have raised the idle speed from to 725 to 775rpm & advanced the timing by 2 degrees in the 8 block section of the tuning tables that address cruising speeds to account for the colder plugs for nitrous. To summarize, the tuner has done everything they can to make the car drivable & acts as though its properly tuned. He also said a 2400rpm stall converter would allow me to idle the car up to 850+rpm which would make the car idle a lot smoother, but why should I have to add a stall converter just to get my car to idle and run correctly? Plus this is a 115 LSA, not a 112, so I would think it would idle fairly smooth anyway. The way I look at it, is that I either have a sub-par tune or all the people writing how their 224 is docile have a higher tolerance level for bucking, surging, etc.

I need to know, what is a reasonable expectation for this type of cam in my car?

Gold Z

I think you need a new tuner.

BigMay60

I have been running a comp xer273 (224/230 114lsa) for over a year. I just added an SC with the same cam. I have never had any of the things happen you are talking about. The car has a healthy lope but I never have experienced any surging or bucking. Also mine cruises smooth at any speed. I am never forced to use the paddles.

The main difference is your cams lift compared to mine I am in the high 580s. Maybe that is the issue, need a more experienced person to answer that. I would be looking for a new tuner.

Also, I have my idle at 750.

Black02SS

I agree with the 2nd post. I might have someone else look at it. I have tuned a 236/243 in both a M6 and A6. NEITHER bucked or had any surging.

SpinMonster

Shifting is a tune issue and can be fixed in a tune if he knew how. He is right about the idle and converter.

Higher idles fix issues with surging but it sound like something is wrong with the base min running airflow to have it bucking.

Your lobes are LSL likely or LSK. XFI and XER doesnt result in such high lift. The reason its significant is because the lobes have greater area of having the valve off the seat which mimmics the area of larger lobes for the time its open. The reason this contributes to driveability is because it contributes to overlap like a larger cam. My guess is that its behaving like a 228/234 or a 230/236 XER lobed cam in this area.

What was the power output? (dyno)

A 230/230 single pattern on a 115+2 XFI/XFI is a +0 overlap cam and doesnt have such bad manners for the LS3. A 224/224 115+2 is great too making 470rwhp on your car. This is if you can get away from the myth that you need a split (huge splits) for the LS3 heads which isnt true.

He can run it richer at part throttle (change stoic to reflect the 14.4 a/f ratio E10 burns at....most fuel has 10% ethanol) and add more timing to tame the surging. The base minimum running airflow table affects this a lot.

05tbh

Something I forgot to mention is that the lobe profile is a custom design from a guy that worked on the C5R team building motors. Not sure if that comes into play or not. Dallas is going to be closest place for me to have it retuned and that's over 5 hours away. I hate to pay someone else $500 to retune the car when it should have been tuned correctly the first time. However, I don't think I have any other options because when he raised the idle this last time, I asked him what else we could do and he said everything checked out okay.

I knew I should have gone with my gut instinct and went with a proven cam manufacturer, but considering the reputation of this shop and that they have been using the cam designer for well over a year, I thought it would be safe. The cam did pick me up 42rwhp/22ftlbs and he said I probably lost 5rwhp/5ftlbs due to the nitrous tune.

vettesweetnos

I believe that there are two different maps for a tune for ac on and ac off. Sounds like they only changed one. A tuner should have no problems tuning for that cam. I have a 223/231 .610 .617 LSA 115+4 in my ls3 A6 and have none of these problems at all. Car runs superb. I suggest a new tuner as well. You pay $500 for a tune and deserve your moneys worth, a dyno and street tune with hp tuners efi live. Try and post a video up of idle/cruise.

Mez

PM Sent.

Welcome to the world of tuning.

I had a similar situation with a well known tuner shop in North Texas and ended up buying HP Tuners and a wide band 02 sensor then returned it myself. Almost as important is being able to drive while scanning to see what is going on. The learning curve is long and steep.

I am a long way from being a pro, but I enjoy learning how it works and making it run better plus better gas mileage.

My cam is the Lingenfelter GT-11 which is 215/231 duration 631/.644 lift with 118 LSA which is a step down from yours. It idles smooth at 750 rpm and drives like stock with no surge or bucking anytime. I would start by backing down ignition timing a few degrees under 1500 rpm but without seeing the car and doing a scan, its difficult to say. There are a few tables that are referenced before coming to the final ignition advance, so someone that knows what they are doing should look at it.

Fore58

Dyno and street tune are the way to go. If your tuner is having so much difficulty, why doesn't he just call a fellow tuner and get some answers....hello? Why should you pay $500 more for a retune....that's absurd?

05tbh

Great input input everyone...thank you.

Spin - you are correct, the car operates as if its a 230+ cam. Its a custom lobe, but it's definitely aggressive not a XFI or XER.

The car made 442rwhp & 424ftlbs after the cam and 400rwhp & 402ftlbs.

Would tuning the VE tables help?

Mez

I don't believe the 2008 don't VE table. My 2005 does, but they stopped using them by 2008. They started using a calculation instead.

I recommend calling your tuner to brainstorm on what to do.

Vegas Panton

The duration/LSA/advance numbers look very streetable. Was the cam checked before install to verify that the cam was ground correctly? I ordered a Patrick G custom cam through Thunder Racing. They used Comp Cams to grind the cam to the requested specifications. Then they measured the cam before they shipped it to me to verify the cam measured to the correct specifications. They were within one degree on duration and spot on with the lift and LSA. Every once in a while a cam is ground with the wrong specifications. If your tuner knows his stuff and still can't get your car to run right, the cam (if ground wrong) could be the problem. Good luck.

BuBbABFP

Its all in the tune budd, I had a 231 234 598 642 111lsa on my ls1 and Nick at Newtech made it drive like almost stock. Previous tuner made it buck and surge like crazy.

05tbh

Yeah the cam came with a Cam Doctor printout verifying the specs. I am going to call the tuner on Monday and relay what issues still exist and have him send me another tune. I have a local shop with a hp tuner that can download it for me.

If this doesn't work, I will have no choice but to find another tuner.

pmj341

the tune is not right!!
most of us have run 228/232 600lift 114lsa and idled fine with A6's, no bad manners at all
you need to find a more EXPIrienced Tuner!!!

BartonekDragRacing

if they dont want to re-tune to fix their poor tune then they are not worth your $. Post their name up on here.

Lethal Performance did my cam install/tune. My car needed an adjustment after a week (It was raining and I didnt want my car driven in the rain) since it was dyno tuned but not driven. So I picked it up anyway and they said it should be almost spot on. It was but needed some minor adjustment. I drove it over and they checked it out without hesitating. They're going to do a nitrous install for me next.

thesubfloor

In addition to the tune being off as others have said, there's only so much you'll be able to do by playing with it and to get rid of all the bucking you'll need to turn off your torque converter lockup clutch at low speeds.

I just put a really big cam in my A6 (don't have all the specs but it has a .666 lift and 110 LSA) and it too would buck at light throttle until I altered my tune to have the lockup not happen until at least 65MPH and in 6th gear.

The reason for this is that our torque converters never achieve full lockup (which is when the motor and transmission are moving at the same speed synonymous with a clutch fully engaged in a manual car) but instead are constantly turning on and off due to PWM (Pulse Width Modulation). GM did this apparently to make the car feel smoother but the downside is that if your cam is even marginally radical it magnifies the difference in the engine operating characteristics to the rear end and in some cases making the car absolutely no fun to drive.

The only downside that I've discovered so far is that my transmission runs a little hotter now but the upside is that if you're driving around town and punch the throttle the RPM jump is almost instantaneous since you no longer have to wait for the lockup clutch to disengage first.

PM me if you'd like any more details about it.

Christopher

TrenAman

224/232 114lsa here A6 LS3, perfectly streetable here!

06-Z0SICK

dude the came has -1.5* of valve overlap. The cam should not be hard at all to dial in. I dont think the tuner has it bang on. Take it somewhere else and have it tuned right or have them fix it. Its easily doable

05tbh

What does your car idle at?