LS7 BTR Stage 4 - low numbers?
Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
LS7 BTR Stage 4 - low numbers?
Hi,
I just cannot let go of the numbers i got when I had my car dynoed. This guy is probably the best when it comes to Corvettes in Sweden, and i trust him, but i know there are LOTS of high quality tuners in America and around the world.
Whats your thoughts? Graph looks like it should?
K&N CAI
Fast Lsxr intake 90mm TB
BTR Stage 4 cam
Stock heads (new valves, seals, guides, rockers etc)
Kooks 1 7/8 headers
Akrapovic 3" x-pipe and titanium exhaust. De-Cat
Granatelli spark plug wires
Quite a lot of bucking / surging 1200-1800 rpm.
Will head to him and try to lessen the big amounts of surging within a week.
Could removing the intake/radiator shield cause it to surge more than it should with this cam?
Any tuning input or advice is much appreciated,
Thank you!
I just cannot let go of the numbers i got when I had my car dynoed. This guy is probably the best when it comes to Corvettes in Sweden, and i trust him, but i know there are LOTS of high quality tuners in America and around the world.
Whats your thoughts? Graph looks like it should?
K&N CAI
Fast Lsxr intake 90mm TB
BTR Stage 4 cam
Stock heads (new valves, seals, guides, rockers etc)
Kooks 1 7/8 headers
Akrapovic 3" x-pipe and titanium exhaust. De-Cat
Granatelli spark plug wires
Quite a lot of bucking / surging 1200-1800 rpm.
Will head to him and try to lessen the big amounts of surging within a week.
Could removing the intake/radiator shield cause it to surge more than it should with this cam?
Any tuning input or advice is much appreciated,
Thank you!
Last edited by pierrel; Jul 3, 2017 at 02:42 PM.
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Have you checked to see if the CAI Throttle-body clamps were tightened enough? You can't just use a Flat-head screw driver to tighten these....it requires a small socket wrench and squeezing them down as much as you possibly can...
All of my bucking/surging went away after I did this.... Check and then reset fuel trims and see if there is a difference... You will be able to tell immediately... It can be a simple mistake overlooked by the shop...
This would also result in lower HP numbers as the intake is not getting all its possible airflow...
If you think that the clamps are tight enough...Tighten more...
Are you getting slower power results in the 2700 to 3800 rpm range and then it picks up around 4k??
I'm betting money on this!
All of my bucking/surging went away after I did this.... Check and then reset fuel trims and see if there is a difference... You will be able to tell immediately... It can be a simple mistake overlooked by the shop...
This would also result in lower HP numbers as the intake is not getting all its possible airflow...
If you think that the clamps are tight enough...Tighten more...
Are you getting slower power results in the 2700 to 3800 rpm range and then it picks up around 4k??
I'm betting money on this!
Last edited by 2L8LUZ; Jul 4, 2017 at 01:30 PM.
Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
Have you checked to see if the CAI Throttle-body clamps were tightened enough? You can't just use a Flat-head screw driver to tighten these....it requires a small socket wrench and squeezing them down as much as you possibly can...
All of my bucking/surging went away after I did this.... Check and then reset fuel trims and see if there is a difference... You will be able to tell immediately... It can be a simple mistake overlooked by the shop...
This would also result in lower HP numbers as the intake is not getting all its possible airflow...
If you think that the clamps are tight enough...Tighten more...
Are you getting slower power results in the 2700 to 3800 rpm range and then it picks up around 4k??
I'm betting money on this!
All of my bucking/surging went away after I did this.... Check and then reset fuel trims and see if there is a difference... You will be able to tell immediately... It can be a simple mistake overlooked by the shop...
This would also result in lower HP numbers as the intake is not getting all its possible airflow...
If you think that the clamps are tight enough...Tighten more...
Are you getting slower power results in the 2700 to 3800 rpm range and then it picks up around 4k??
I'm betting money on this!
Ive done pretty much everything on this engine myself, except install the cam, that was done by the previous owner.
Reset fuel trims using HP tuners or ?
Thanks again!
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
Thanks, and happy 4th!
Well, the car feels sluggish from low rpm until about 4k where both power and torque increases, also shown in the graph in my first post. Its not as crisp in the lower RPM range compared to when the cam is really put to work.
I was thinking add timing during lower rpm to get a bit more punch, but it seems you remove timing to lessen the surge.
Well, the car feels sluggish from low rpm until about 4k where both power and torque increases, also shown in the graph in my first post. Its not as crisp in the lower RPM range compared to when the cam is really put to work.
I was thinking add timing during lower rpm to get a bit more punch, but it seems you remove timing to lessen the surge.
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
It's not too much timing...this is your problem..id bet my left arm on it...
The bucking/surging ...gave it away
Its no big deal to tighten down the clamps more and reset your battery...
It won't effect the tune...
This WILL solve your problem
The bucking/surging ...gave it away
Its no big deal to tighten down the clamps more and reset your battery...
It won't effect the tune...
This WILL solve your problem
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Even very little amounts of timing down low would still give you a crispness...
After you tighten the clamps back down you will be rich.... which is just fine..because u get all your power back and restore your low rpm acceleration.... just have your tuner take more fuel out to get you to optimal range
After you tighten the clamps back down you will be rich.... which is just fine..because u get all your power back and restore your low rpm acceleration.... just have your tuner take more fuel out to get you to optimal range
Last edited by 2L8LUZ; Jul 4, 2017 at 02:56 PM.
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Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
We've now added some timing at low rpm's, and the engine responds better, but sadly with more bucking/surging. In 2nd gear the bucking is causing an increase/decrease of 200rpm. Will go back this week and try some more.
Thanks 2L8LUZ!
Last edited by pierrel; Jul 9, 2017 at 11:01 AM.
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Im sorry, but this was probably not the cause. Everything was clamped down real tight, and there are no leaks around the intake or any vacuum hoses.
We've now added some timing at low rpm's, and the engine responds better, but sadly with more bucking/surging. In 2nd gear the bucking is causing an increase/decrease of 200rpm. Will go back this week and try some more.
Thanks 2L8LUZ!
We've now added some timing at low rpm's, and the engine responds better, but sadly with more bucking/surging. In 2nd gear the bucking is causing an increase/decrease of 200rpm. Will go back this week and try some more.
Thanks 2L8LUZ!
If you fixed the air leaks and just added more timing without resetting your bucking and surging will be even worse as described...
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
you also have to use a small rachet to secure the clamps... screwdrivers won't cut it
Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
There were no air leaks evident, and I reset the ECM and he did have a look at the fuel trims. Don't know i he reset them, or just tweaked with the added timing. Isn't everything reset when flashing the new tune?
Team Owner
Joined: Nov 2007
Posts: 24,035
Likes: 2,342
From: Gilbert AZ
Flash new tune resets trims.
A stage 4 cam is going to buck/surge at light throttle <2k. That is part of having a big cam. Without driving the car, hard to say if your car is normal or if it could be improved with tuning.
A stage 4 cam is going to buck/surge at light throttle <2k. That is part of having a big cam. Without driving the car, hard to say if your car is normal or if it could be improved with tuning.
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Indeed i used a ratchet to properly secure the clamps. They were already really tight from when i installed them, so i couldn't really tighten them more.
There were no air leaks evident, and I reset the ECM and he did have a look at the fuel trims. Don't know i he reset them, or just tweaked with the added timing. Isn't everything reset when flashing the new tune?
There were no air leaks evident, and I reset the ECM and he did have a look at the fuel trims. Don't know i he reset them, or just tweaked with the added timing. Isn't everything reset when flashing the new tune?
keep driving it... if your problems still occur locate a new tuner....I know nobody wants to hear that..
I can cruise in 6th gear at 1200 rpms with no issues
Last edited by 2L8LUZ; Jul 9, 2017 at 01:24 PM.
Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
Thanks!
No.... The answer is Yes/No... The changes put in place change factors but doesn't adapt to driving habbits...It takes 250 miles for that to fully adjust...the car will act differently around 100 or so miles after new tune is flashed...
keep driving it... if your problems still occur locate a new tuner....I know nobody wants to hear that..
I can cruise in 6th gear at 1200 rpms with no issues
keep driving it... if your problems still occur locate a new tuner....I know nobody wants to hear that..
I can cruise in 6th gear at 1200 rpms with no issues
Thanks!
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Here's a possibility... I know its a far stretch but its the little things that you can mark off your checklist... Have you ensured that your plug wires are secure and haven't backed off either the plug or coil ?? This will cause that as well... Check to see if they are snapped in place... The plug wires will be over the plugs but with cams this size my comes off all the time..
Last edited by 2L8LUZ; Jul 10, 2017 at 12:23 PM.
Thread Starter
Instructor
Joined: Oct 2016
Posts: 234
Likes: 10
From: Stockholm, Sweden
Here's a possibility... I know its a far stretch but its the little things that you can mark off your checklist... Have you ensured that your plug wires are secure and haven't backed off either the plug or coil ?? This will cause that as well... Check to see if they are snapped in place... The plug wires will be over the plugs but with cams this size my comes off all the time..
Now they are all secured properly. The Granatelli wires require 2 clicks to be heard on the coil side, and 1 click on the spark plug side. Didn't help though.
Racer
Joined: Apr 2017
Posts: 434
Likes: 35
Its not that far of a stretch. Found one that was a little loose this last weekend when going over things in the engine bay.
Now they are all secured properly. The Granatelli wires require 2 clicks to be heard on the coil side, and 1 click on the spark plug side. Didn't help though.
Now they are all secured properly. The Granatelli wires require 2 clicks to be heard on the coil side, and 1 click on the spark plug side. Didn't help though.
Last edited by 2L8LUZ; Jul 10, 2017 at 03:47 PM.