BTR Stage 3 Cam Low Speed Surging Issues
Thread Starter
Racer
Joined: Aug 2005
Posts: 298
Likes: 12
BTR Stage 3 Cam Low Speed Surging Issues
I recently had my LS1 engine rebuilt and it was recommended I use the Brian Tooley Racing (BTR) stage 3 cam. After dyno tuning it pulled around 400 RWHP. The car has 373 rear gears and is a 6 speed manual. The problem is that the car surges in 2nd, 3rd and 4th gears in any speed under 45mph. It was dyno tuned and them tuned again to eliminate the surging. No Luck. The surging makes the car very uncomfortable to drive except at highway speeds. Anyone else have this issue? The work was done by very reputable tuner outfit in NC.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,668
I recently had my LS1 engine rebuilt and it was recommended I use the Brian Tooley Racing (BTR) stage 3 cam. After dyno tuning it pulled around 400 RWHP. The car has 373 rear gears and is a 6 speed manual. The problem is that the car surges in 2nd, 3rd and 4th gears in any speed under 45mph. It was dyno tuned and them tuned again to eliminate the surging. No Luck. The surging makes the car very uncomfortable to drive except at highway speeds. Anyone else have this issue? The work was done by very reputable tuner outfit in NC.
Le Mans Master
Joined: Sep 2017
Posts: 5,232
Likes: 1,529
From: Pasadena, MD
2023 C5 of the Year Finalist - Modified
“Bucking” tends to happen under a certain rpm, not mph.
So if you’re in 2nd at 45 mph it bucks/surges?
Grinder I think the btr stage 3 is a 112.5 lobe separation but could be wrong.
So if you’re in 2nd at 45 mph it bucks/surges?
Grinder I think the btr stage 3 is a 112.5 lobe separation but could be wrong.
Thread Starter
Racer
Joined: Aug 2005
Posts: 298
Likes: 12
I know nothing about "stages", but I do know about specs. If the cam you've chosen has 230° duration, or more, .600" lift, on a 112° LSA, or less, and you're running it in a 346 cubic inch engine, you're going to have to find an Einstein tuner to reduce the surge, but even he wont be able to eliminate it. Wallace racing has an online cam overlap calculator. If your cam has 10°-15°, or more overlap, youre going to have a hard time getting it to run buck/surge free. I have a 232°/250° cam, on a 112° LSA, in an LS7. It has 17° of overlap! It still has a slight buck in it at a light, steady throttle under 50mph. This is a 427 and an A4, both of which help tame the cam. I'd sure like to see who recommended that cam. If you're primarily driving on the street, I'll bet Brian Tooley didn't recommend it. Just saying, I think you're expecting a lot out of a big cam in a 346. Power? YES! Drivability? NO!! My opinion.
Specs: 231/244 .630"/.615" 112.5+2.5
I'll go back to the engine builder and see what remedy if any I can obtain. I believe you are spot on. FYI: RPM range is 1200-2500 for the surging.
Safety Car
Joined: Apr 2017
Posts: 3,708
Likes: 344
From: Texas By God
I have the same cam. And yes if RPM drops below 2400 - 2500 it will surge. Big deal down shift. You will get surging in the parking lots in 1st-2nd gear at low speeds push in the clutch. down shift or speed up. On the highway in 6th at 75 your at 1800 and not surging. It is cammed and not a stock grocery getter, drive it.
Le Mans Master
Joined: Sep 2017
Posts: 5,232
Likes: 1,529
From: Pasadena, MD
2023 C5 of the Year Finalist - Modified
If I swapped cams and made less power and the car sucked to drive I'd be pretty upset.
I'd imagine going to a 4.11 would help you A LITTLE.
I have a 230/236 .592/.602 114 and it surged a little. I changed to 3.90s and it helped a good bit in parking lots.
Like Texan 79423 wrote, just keep the Rs up.
I'd imagine going to a 4.11 would help you A LITTLE.
I have a 230/236 .592/.602 114 and it surged a little. I changed to 3.90s and it helped a good bit in parking lots.
Like Texan 79423 wrote, just keep the Rs up.
Race Director
Joined: Oct 2004
Posts: 12,864
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operation.......
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Race Director
Joined: Oct 2004
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I just checked the overlap, and it comes in at 12.5°. Not terrible, but not a super smooth running street cam. Perhaps the OP could try advancing the cam. Many street cams are advanced 4°, or it's ground in. If his is ground in, you'd need another 1.5° to hit 4° advance. OP, if you do this, you're going to go through virtually all the labor it would take to just change cams, and it may not make any difference. I'm an old fart@68. If I was in my 30s or 40s, with an M6 trans, I'd keep the cam, and give the tires HELL!!
But thats me. I'll say this; your car should scoot pretty damn good with that cam!!
But thats me. I'll say this; your car should scoot pretty damn good with that cam!!
Pro
Joined: Jul 2007
Posts: 539
Likes: 117
From: New Braunfels Texas
I have the BTR Stage 2 which is 227/238 duration at .050 and I am pretty happy with the drivability of it. It needs 1st gear at low speeds in a parking lot but is pretty surge free everywhere else. Still makes 400 plus at rear wheels with stock heads and has a pretty choppy idle. I thought about the stage 3 but now am glad I went with the 2. I did have it tuned twice with second tuner making a noticeable difference in the low speed drivability. So maybe a better tune and getting used to driving it at a little higher rpm's will save you the money of a new cam..?
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,668
I have the BTR Stage 2 which is 227/238 duration at .050 and I am pretty happy with the drivability of it. It needs 1st gear at low speeds in a parking lot but is pretty surge free everywhere else. Still makes 400 plus at rear wheels with stock heads and has a pretty choppy idle. I thought about the stage 3 but now am glad I went with the 2. I did have it tuned twice with second tuner making a noticeable difference in the low speed drivability. So maybe a better tune and getting used to driving it at a little higher rpm's will save you the money of a new cam..?
Racer
Joined: Feb 2021
Posts: 284
Likes: 118
From: Southern Indiana
I run the btr stage 3 in my car which was recommended by btr and the only issue I had was when it would get below 1500 but now that I have 4.10’s in my car it’s pretty close to driving a stock car so imo the stage 3 is pretty good for the street that’s the only place mine goes it’s not a track and will probably never see one
Safety Car
Joined: Oct 2007
Posts: 4,222
Likes: 1,080
From: South Florida
You probably just need to move the Injector phase to spray after exhaust valve close.
The phenomenon to which you refer often referred to as 'trailer hitching'
https://forum.hptuners.com/showthrea...l=1#post683180
https://forum.hptuners.com/showthrea...l=1#post242076
https://forum.hptuners.com/showthrea...l=1#post470537
The phenomenon to which you refer often referred to as 'trailer hitching'
https://forum.hptuners.com/showthrea...l=1#post683180
https://forum.hptuners.com/showthrea...l=1#post242076
https://forum.hptuners.com/showthrea...l=1#post470537
