Converter or tune problem???

[helodown66]

This is my first post. Please be patient with me. I am 66 years young and this is my first fun car.

I have a '02 Camaro with A/trans. It has all the "SLP" bolt on up grades and a Torquer 2 cam 232/234, .595"/.598", 113 LSA, and 225cc 2.5 CNC Ported Heads, and an after market SLP 3300-3500 torque converter. The dynojet shows 425 wrhp and 380 ft. pounds torque. It runs pretty well in my estimation, however, I am experiencing "Bucking", "surging" or "grabing" when I am at speeds of less than 40 MPH when I let off of the gas or when I am going slow with very little or no gas pedal. I have resorted to down shifting into either 3 or 2 when at low speed to keep up the RPM's and then the problem goes away.

I have had several tuners look at and fool with the tune, all with little to no improvement. I have also drilled out the small hole in the throttle plate by an extra 1/16 with out any improvement. I was told to enlarge in very small steps, so I am reluctant to go any larger without more feed back.

Then this A.M. I was watching the "Speed" channel and they were talking about the Converter and described the "Grabing", which is exactly what I am experiencing. My car only has a total of 6,000 miles and only 2,000 miles since all the mods were done.

From what I have tried to describe, could I be experiencing converter problems. Can this be fixed via tune?, is there a lock out switch? or do I need to change out converters?

I do have a new performa built trans T-3 with a 3000 stall still new in the box in the garage. Is it time to make the change over? and when I install the new trans & converter do I need to change my tune at the same time?

I understand I have asked more than one question in this post, but I would appreciate some input from you veterans.

[bills98ta]

The torque converter is a locker, which allows it to lock at lower rpm's, causing to buck.( running lower rpm's that the cam is rated for ) It is, somewhat the nature of the beast, but an experienced tuner should be able to calm it down. I run a pretty big cam, and when I'm lugging it at low rpm, I sometimes tap the break pedal to release the converter, which allows it to slip & smooth out. I doubt to many other people could just go cruising in it smoothly !!! Good Luck !!!

[JaycenK]

You should be able to hit the brake and the PCM should unlock the converter like bills said.

[fieropope]

im curious now,is their any way to tune out lockup until 4th?if so why cant they do it and solve this issue.

[JaycenK]

HUM right now on my monster built trans I don't lockup in 3rd while the manual valve is in the OD position. I don't have a tune but the trans has a reworked valve body. It just shifts to 4th gear and then locks up

[fieropope]

well i know of ways to do it mechanically on 700r4s im pretty sure i could do the same on the 4ls but haven tried, but if you could have it done when the tune is done it would save that hassle.

[helodown66]

I installed the new trans & stall converter this last weekend. The problem continues. I have tried to hit the brake softly and hit it hard and not change.

The old stall was a 3300-3500 and the new stall is a 3000, so I am told I will need to change my tune.

I may also be experiencing "Cam Stall" as I am told I have a pretty big cam.

So next step is to work on the tune.

Appreciate your input.

[performabuilt]

You can raise the lockup point i would sugest above 50mph in 4th only as a good setting in tuning you are experincing cam surge

[helodown66]

You can raise the lockup point i would sugest above 50mph in 4th only as a good setting in tuning you are experincing cam surge

Thank you for the info. 3 questions?

Can the "Cam Surge" be tuned out or is it the nature of the beast.

Cooler lines, which line is the out put and which line is the return line?

If I wanted quicker or harder shifts, what should I change? on the tune table?

[SaBala]

I am running a Yank SS3600, and it is a great converter. Normal driving isnt a problem at all, just takes a few more RPMs to get it moving from a stop. When going WOT it hits hard.

[Autoslick]

This is my first post. Please be patient with me. I am 66 years young and this is my first fun car.

I have a '02 Camaro with A/trans. It has all the "SLP" bolt on up grades and a Torquer 2 cam 232/234, .595"/.598", 113 LSA, and 225cc 2.5 CNC Ported Heads, and an after market SLP 3300-3500 torque converter. The dynojet shows 425 wrhp and 380 ft. pounds torque. It runs pretty well in my estimation, however, I am experiencing "Bucking", "surging" or "grabing" when I am at speeds of less than 40 MPH when I let off of the gas or when I am going slow with very little or no gas pedal. I have resorted to down shifting into either 3 or 2 when at low speed to keep up the RPM's and then the problem goes away.

I have had several tuners look at and fool with the tune, all with little to no improvement. I have also drilled out the small hole in the throttle plate by an extra 1/16 with out any improvement. I was told to enlarge in very small steps, so I am reluctant to go any larger without more feed back.

Then this A.M. I was watching the "Speed" channel and they were talking about the Converter and described the "Grabing", which is exactly what I am experiencing. My car only has a total of 6,000 miles and only 2,000 miles since all the mods were done.

From what I have tried to describe, could I be experiencing converter problems. Can this be fixed via tune?, is there a lock out switch? or do I need to change out converters?

I do have a new performa built trans T-3 with a 3000 stall still new in the box in the garage. Is it time to make the change over? and when I install the new trans & converter do I need to change my tune at the same time?

I understand I have asked more than one question in this post, but I would appreciate some input from you veterans.

Ask the converter company if the converter has a clutch damper or not. I just bought one and that is a question they asked me if I needed it or not. It was recommended to me for street driving.

[Marc 85Z28]

Thank you for the info. 3 questions?

Can the "Cam Surge" be tuned out or is it the nature of the beast.

Cooler lines, which line is the out put and which line is the return line?

If I wanted quicker or harder shifts, what should I change? on the tune table?

It's cam surge, and it can be tuned out. Most tuners claim they can do this, but in reality most cannot. There are a few guys out there that are very good, but nowhere near where you are A mail order tune won't cut it either. So you'll either need to just deal with it or take a VERY long road trip to someone who knows what they're doing.

With a cam of that size, I would expect any truly competent tuner to get the engine to behave above at least 1400RPM under load. I've got a simliar setup, albeit with a cam that has nearly an additional 10 degress duration that will do 1500rpm locked in 4th gear without issues.

[Firebirdjones]

Performabuilt was right on the money, you just simply need to go in the tune and move the lockup mph up a bit higher. Factory has them engage as low as 36-38 mph in the stock tune if I remember correctly.

How much rearend gear you run will dictate how soon you can lockup the converter. Example: A car with a large cam running a 3.73 gear can lock the converter up at a lower MPH because the engine rpm would be a tad higher anyway as compared to a car with a 2.73 rearend. It's something you will have to play with in the tune and find a happy spot for your car.

[Blue Thunder 42]

I was going to say it could be a bad 02 sensor, but after reading that tuners have tried to fix it or tune it out they would have determined and told you if a 02 sensor was bad.
Good luck with that bad ass cam in a auto.

[Firebirdjones]

I was going to say it could be a bad 02 sensor, but after reading that tuners have tried to fix it or tune it out they would have determined and told you if a 02 sensor was bad.
Good luck with that bad ass cam in a auto.

It's not that big of a cam,,,duration at .050 is only in the mid 230 range, and the lobe sep is spread out to 113. Should work fine in an auto with the right converter. Not like we are talking about a cam on a 108 with duration in the 250 range,,,lol.

[Blue Thunder 42]

Ok true,
I have a 219/229, 525 duration and 112 lobe sep with 1.8 rockers and mines a bit lopy.
My bro had it in his auto with stock converter and it was too much. kept stalling on him at lights.
helodown66's just sounds alot bigger than mine, am I wrong?

[Firebirdjones]

Ok true,
I have a 219/229, 525 duration and 112 lobe sep with 1.8 rockers and mines a bit lopy.
My bro had it in his auto with stock converter and it was too much. kept stalling on him at lights.
helodown66's just sounds alot bigger than mine, am I wrong?

Ya it's a bit bigger than yours. Sounds like you have the GM hot cam. It's rather mild with a little sound, but I wouldn't try running it with a stock converter. Although some tricks with tuning could get you around the stock converter with a cam that mild.
Any instance where you get into a camshaft that has a decent amount of overlap,,,,it is going to cause idle problems in an auto if the right converter is not installed.

Which is why GM never offered the auto trans behind the hotter solid lifter cam engines until 1969,,,because the converter technoligy just wasn't developed enough at the time to support it.

[helodown66]

It's cam surge, and it can be tuned out. Most tuners claim they can do this, but in reality most cannot. There are a few guys out there that are very good, but nowhere near where you are A mail order tune won't cut it either. So you'll either need to just deal with it or take a VERY long road trip to someone who knows what they're doing.

With a cam of that size, I would expect any truly competent tuner to get the engine to behave above at least 1400RPM under load. I've got a simliar setup, albeit with a cam that has nearly an additional 10 degress duration that will do 1500rpm locked in 4th gear without issues.

Marc85Z28,
Whom would you suggest that "knows what they're doing"? Yes, I live in the middle of no where, i.e. NW corner of MT.

I greatly appreciate everyone's input.

Thank you,

Helodown66

[helodown66]

Thank you everyone for your input.

I agree, I do not think I have a converter problem.

I have changed the tune so that converter does not lock until over 50 MPH.

Then with the help of a tuner via e-mail, I have reduced the timing at the lower RPMs and lower % of throttle opening, so that the car is much happier than it was.

I don't mind the "Lopy" cam, but was not enjoying the "bucking or lurching", which was taking place. The reduced timing has improved the situation by 80%, which is sig.

When I purchased the Cam & Heads, I asked the speed shop for their opinion and that package was recommended. I have 4:10 gears and the difference before and after installing this package was the difference between night and day, so I am very happy to say the least. The only problem now is I can not get the car to "Hook", even with street drag radials.
I guess that is a good problem to have, as I want to keep the car as stock looking as possible on the outside.

Again, thank you, as I have learned a great deal with this forum.

Now to the new rear end. I am leaning on going to 3:90's rather than 4:10's, I am open to comments.

Helodown66

[Marc 85Z28]

Marc85Z28,
Whom would you suggest that "knows what they're doing"? Yes, I live in the middle of no where, i.e. NW corner of MT.

I greatly appreciate everyone's input.

Thank you,

Helodown66

I know of a few really good guys in the Mid-Atlantic area. I don't know of any shops out your way.