[Z06] Big cam guys.... who went to 4.10 gears?
09-08-2015, 09:24 AM
#61
Pro
Thread Starter
Funny how guys that say going with a different rear gear wouldn't resolve (help) my large cam issues haven't replied to this thread.
Changing out the diff to a 3.90 was the BEST thing I ever did. After driving the car for more than a week, I'm so glad I did it.
Hopefully this thread will help someone else that has/had the same issues I had.
Changing out the diff to a 3.90 was the BEST thing I ever did. After driving the car for more than a week, I'm so glad I did it.
Hopefully this thread will help someone else that has/had the same issues I had.
09-08-2015, 09:36 AM
#62
Funny how guys that say going with a different rear gear wouldn't resolve (help) my large cam issues haven't replied to this thread.
Changing out the diff to a 3.90 was the BEST thing I ever did. After driving the car for more than a week, I'm so glad I did it.
Hopefully this thread will help someone else that has/had the same issues I had.
Changing out the diff to a 3.90 was the BEST thing I ever did. After driving the car for more than a week, I'm so glad I did it.
Hopefully this thread will help someone else that has/had the same issues I had.
For one, what exactly do you consider "issues"??? You and I most obviously do not share the same definition. Or maybe, your "issues" were so bad, the gear changed helped, but you still have "issues" that I would have "issue" with?
So let's clear this up a bit, so others, like me, don't blow a few grand on a gear swap thinking "my" issues will be resolved, but find out they are not. Cause if a simple gear swap will resolve reversion induced engine issues, I'll do the swap myself this winter. That would be a hell of a lot easier than another cam swap.
Do a test for me, if you'd be so inclined. Fifth gear, 1600 -2000 rpm, steady state. Does the engine run smooth, or do you have minor stumble/surge/cough? What does your fuel trims look like in this rpm range?
First gear, dead stop to roll under 15 mph in a parking lot. Do you have to ride the clutch at all, or can you just put around?
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Millenium Z06 (09-18-2015)
09-08-2015, 09:45 AM
#63
I'm with Michael on this one. I always thought the gears did two things which made sense for big cam guys:
1) Optimizing shift points for the given power band.
2) Keeps the engine out of the problem spots in the RPM like Michael D was suggesting. It doesn't fix the problem itself but keeps you from having to drive in that part of the RPM's as often as you would with the stock 3.42 ratios.
------------------------
All that being said, if I put gears in my car, its because I want to go faster, not because I made a poor choice of camshaft/head combination.
1) Optimizing shift points for the given power band.
2) Keeps the engine out of the problem spots in the RPM like Michael D was suggesting. It doesn't fix the problem itself but keeps you from having to drive in that part of the RPM's as often as you would with the stock 3.42 ratios.
------------------------
All that being said, if I put gears in my car, its because I want to go faster, not because I made a poor choice of camshaft/head combination.
09-08-2015, 10:23 AM
#64
Pro
Thread Starter
Well it could be that some of us, like myself, do not read every thread or response. But I did see this jab, so I'll respond.
For one, what exactly do you consider "issues"??? You and I most obviously do not share the same definition. Or maybe, your "issues" were so bad, the gear changed helped, but you still have "issues" that I would have "issue" with?
So let's clear this up a bit, so others, like me, don't blow a few grand on a gear swap thinking "my" issues will be resolved, but find out they are not. Cause if a simple gear swap will resolve reversion induced engine issues, I'll do the swap myself this winter. That would be a hell of a lot easier than another cam swap.
Do a test for me, if you'd be so inclined. Fifth gear, 1600 -2000 rpm, steady state. Does the engine run smooth, or do you have minor stumble/surge/cough? What does your fuel trims look like in this rpm range?
First gear, dead stop to roll under 15 mph in a parking lot. Do you have to ride the clutch at all, or can you just put around?
For one, what exactly do you consider "issues"??? You and I most obviously do not share the same definition. Or maybe, your "issues" were so bad, the gear changed helped, but you still have "issues" that I would have "issue" with?
So let's clear this up a bit, so others, like me, don't blow a few grand on a gear swap thinking "my" issues will be resolved, but find out they are not. Cause if a simple gear swap will resolve reversion induced engine issues, I'll do the swap myself this winter. That would be a hell of a lot easier than another cam swap.
Do a test for me, if you'd be so inclined. Fifth gear, 1600 -2000 rpm, steady state. Does the engine run smooth, or do you have minor stumble/surge/cough? What does your fuel trims look like in this rpm range?
First gear, dead stop to roll under 15 mph in a parking lot. Do you have to ride the clutch at all, or can you just put around?
First, please go re-read my original post and the response(s) I made on the first page. "MY" issues were fairly well spelled out and the rear gear resolved those issue for me for the most part. My main issue was low speed, low RPM, part throttle, higher gears in stop and go traffic. If I was 50% throttle or more in the above scenario the engine ran fine for the most part. I could never lug it around like a stock LS7 but it was good enough.
I never made any comments about wanting my car to run/idle like stock. I simply wanted to be able to drive my car on the street and use more than 1st thru 3rd gear.
Second, my issues were bad enough that I was either going to sell the car or find a way to resolve the issues I had to make it enjoyable on the street. My old school mentality was to change the rear gear to bring the revs up to remove most if not all of my driveabilty issues.
The car no longer stumbles or bucks from surging even with short shifting so I am thrilled. I can use 6th on the frwy now at any speeds above 65mph although it prefers 75mph or better. I can drive at 45mph on the street in 4th gear with little to no surging. Anything below 40mph requires 3rd gear. Again, the part throttle or off throttle still creates some cam surge but nothing like it was.
In your 5th gear scenario I would have slight surge/bump/bucking but nothing like before. I would say it's tolerable but not remotely close to stock. I have no idea what my fuel/trim looks like. I would have to ask the tuner for files I guess.
I haven't tried to release the clutch without the throttle pedal BUT I would think the car would stall. Again, I would have to give it a go and see what happens. lol
Again, none of these issues were what I was complaining about. Had I been the one to build this car I might have looked more into the tuning, component matching, etc but I didn't. This is a Lingenfelter 660 kit that I bought and am having to "fix" to make it enjoyable to drive on the street.... for me. Lingenfelter is very specific with the 660 kit when it says it's NOT streetable and to go with their 630 kit if that is what you mainly want.
The car flat out RIPS at WOT and anything above 3,500 RPM. I love the car as it was but wanted to make it better and the rear gear did just that.
Tuning, component matching, intake matching, etc, etc.... isn't an option for me.
09-08-2015, 10:27 AM
#65
Pro
Thread Starter
I'm with Michael on this one. I always thought the gears did two things which made sense for big cam guys:
1) Optimizing shift points for the given power band.
2) Keeps the engine out of the problem spots in the RPM like Michael D was suggesting. It doesn't fix the problem itself but keeps you from having to drive in that part of the RPM's as often as you would with the stock 3.42 ratios.
------------------------
All that being said, if I put gears in my car, its because I want to go faster, not because I made a poor choice of camshaft/head combination.
1) Optimizing shift points for the given power band.
2) Keeps the engine out of the problem spots in the RPM like Michael D was suggesting. It doesn't fix the problem itself but keeps you from having to drive in that part of the RPM's as often as you would with the stock 3.42 ratios.
------------------------
All that being said, if I put gears in my car, its because I want to go faster, not because I made a poor choice of camshaft/head combination.
09-08-2015, 12:00 PM
#66
Not really a jab. Just good ribbing between car guys. I know how guys get on the forums.... let's be nice.
First, please go re-read my original post and the response(s) I made on the first page. "MY" issues were fairly well spelled out and the rear gear resolved those issue for me for the most part. My main issue was low speed, low RPM, part throttle, higher gears in stop and go traffic. If I was 50% throttle or more in the above scenario the engine ran fine for the most part. I could never lug it around like a stock LS7 but it was good enough.
I never made any comments about wanting my car to run/idle like stock. I simply wanted to be able to drive my car on the street and use more than 1st thru 3rd gear.
Second, my issues were bad enough that I was either going to sell the car or find a way to resolve the issues I had to make it enjoyable on the street. My old school mentality was to change the rear gear to bring the revs up to remove most if not all of my driveabilty issues.
The car no longer stumbles or bucks from surging even with short shifting so I am thrilled. I can use 6th on the frwy now at any speeds above 65mph although it prefers 75mph or better. I can drive at 45mph on the street in 4th gear with little to no surging. Anything below 40mph requires 3rd gear. Again, the part throttle or off throttle still creates some cam surge but nothing like it was.
In your 5th gear scenario I would have slight surge/bump/bucking but nothing like before. I would say it's tolerable but not remotely close to stock. I have no idea what my fuel/trim looks like. I would have to ask the tuner for files I guess.
I haven't tried to release the clutch without the throttle pedal BUT I would think the car would stall. Again, I would have to give it a go and see what happens. lol
Again, none of these issues were what I was complaining about. Had I been the one to build this car I might have looked more into the tuning, component matching, etc but I didn't. This is a Lingenfelter 660 kit that I bought and am having to "fix" to make it enjoyable to drive on the street.... for me. Lingenfelter is very specific with the 660 kit when it says it's NOT streetable and to go with their 630 kit if that is what you mainly want.
The car flat out RIPS at WOT and anything above 3,500 RPM. I love the car as it was but wanted to make it better and the rear gear did just that.
Tuning, component matching, intake matching, etc, etc.... isn't an option for me.
First, please go re-read my original post and the response(s) I made on the first page. "MY" issues were fairly well spelled out and the rear gear resolved those issue for me for the most part. My main issue was low speed, low RPM, part throttle, higher gears in stop and go traffic. If I was 50% throttle or more in the above scenario the engine ran fine for the most part. I could never lug it around like a stock LS7 but it was good enough.
I never made any comments about wanting my car to run/idle like stock. I simply wanted to be able to drive my car on the street and use more than 1st thru 3rd gear.
Second, my issues were bad enough that I was either going to sell the car or find a way to resolve the issues I had to make it enjoyable on the street. My old school mentality was to change the rear gear to bring the revs up to remove most if not all of my driveabilty issues.
The car no longer stumbles or bucks from surging even with short shifting so I am thrilled. I can use 6th on the frwy now at any speeds above 65mph although it prefers 75mph or better. I can drive at 45mph on the street in 4th gear with little to no surging. Anything below 40mph requires 3rd gear. Again, the part throttle or off throttle still creates some cam surge but nothing like it was.
In your 5th gear scenario I would have slight surge/bump/bucking but nothing like before. I would say it's tolerable but not remotely close to stock. I have no idea what my fuel/trim looks like. I would have to ask the tuner for files I guess.
I haven't tried to release the clutch without the throttle pedal BUT I would think the car would stall. Again, I would have to give it a go and see what happens. lol
Again, none of these issues were what I was complaining about. Had I been the one to build this car I might have looked more into the tuning, component matching, etc but I didn't. This is a Lingenfelter 660 kit that I bought and am having to "fix" to make it enjoyable to drive on the street.... for me. Lingenfelter is very specific with the 660 kit when it says it's NOT streetable and to go with their 630 kit if that is what you mainly want.
The car flat out RIPS at WOT and anything above 3,500 RPM. I love the car as it was but wanted to make it better and the rear gear did just that.
Tuning, component matching, intake matching, etc, etc.... isn't an option for me.
I may try gearing. 6th gear is worthless where I live anyway.
I also would hate for anyone to go with too much cam thinking a gear change will make it drive like stock.
09-08-2015, 12:12 PM
#67
Pro
Thread Starter
I'm being sincere when I say I'm happy for you. I have spent thousands of dollars and probably spent 100 hours trying to tune around the issues I am having. A gear change has always been in the back of my mind, as another option to try. I'm really quite fed up with wasting my time and money screwing with this engine. Spending another 4K and all the time and labor to swap out cam and heads, again, just pisses me off. Pisses me off cause I let others talk me into this combination of parts that I friggin knew I'd have issues with.
I may try gearing. 6th gear is worthless where I live anyway.
I also would hate for anyone to go with too much cam thinking a gear change will make it drive like stock.
I may try gearing. 6th gear is worthless where I live anyway.
I also would hate for anyone to go with too much cam thinking a gear change will make it drive like stock.
If I knew I was never using 6th I think I would go with a 4.10 and just drive on drag radials all the time. Oh.... A negative is the rears break loose easier with the 3.90's so I assume it's worse with the 4.10's
A plus with the rear gear change it feels like (I know.... it didn't add any HP for anyone reading this and thinking I am being literal) I picked up 50-60HP the way it plants me in the seat in the mid range now. I actually laughed out loud once the clutch was broken in and I ran it through the gears.
Money well spent for me.
09-08-2015, 02:05 PM
#68
Le Mans Master
A plus with the rear gear change it feels like (I know.... it didn't add any HP for anyone reading this and thinking I am being literal) I picked up 50-60HP the way it plants me in the seat in the mid range now. I actually laughed out loud once the clutch was broken in and I ran it through the gears.
If it wasn't for all the EPA / gas mileage overhead, I think GM would have installed 3.90's stock.My issue is DTE seems to be out of the running on this one, and RPM seems to be VERY proud of their work - might I ask what you paid RPM for the new setup (I always do my own labor, so please don't include the removal or installation costs)?
09-08-2015, 02:10 PM
#69
Pro
Thread Starter
If it wasn't for all the EPA / gas mileage overhead, I think GM would have installed 3.90's stock.My issue is DTE seems to be out of the running on this one, and RPM seems to be VERY proud of their work - might I ask what you paid RPM for the new setup (I always do my own labor, so please don't include the removal or installation costs)?
Plus core + shipping.... I don't have that info in front of me though.
09-08-2015, 06:42 PM
#70
I have an 09' Z06 with the LPE 660 kit with the GT21 cam. Cam surge is getting on my nerves and makes driving my car on the street less enjoyable. I drive around in 3rd to keep the revs above 2,500.
I was wanting to know if I put in 3.90 or 4.10 rear gear if it would help with the surging by keeping the revs higher and allow me to use 4th and 5th gear more? Also I would think that the shorter rear gear would make starting in 1st gear much easier right?
I've been reading up on this and would really like to hear from guys that have larger cams and possibly had the same issue(s) I have.
If you did swap form OE to 3.90 or 4.10 who did you buy the parts from?
I was wanting to know if I put in 3.90 or 4.10 rear gear if it would help with the surging by keeping the revs higher and allow me to use 4th and 5th gear more? Also I would think that the shorter rear gear would make starting in 1st gear much easier right?
I've been reading up on this and would really like to hear from guys that have larger cams and possibly had the same issue(s) I have.
If you did swap form OE to 3.90 or 4.10 who did you buy the parts from?
09-08-2015, 07:00 PM
#71
Pro
Thread Starter
Have the same LPE 660 package as you with the GT21 cam with 4.10 gears. I dont really like the 4.10 gear, I think its too much for the car as traction becomes a big issue even with drag radials. Surging is still and issue, no way around it says Brent from LPE. I am actually looking to go back down to 3.73 and change the 5th and 5th gear transmission ratios to .80 and .63 from RPM Transmission. Along with a cam change to Brian Tooley Stage 3, so basically going to change my entire setup away from the LPE package.
09-08-2015, 07:37 PM
#72
Le Mans Master
Bought mine with the TSP LS7S cam in it & surge was beyond annoying. It was because of the **** tune on it. Had a competent tuner, Andrew @ CSP, have at it & he eliminated most of it & the car is fun to drive again. You'll never get rid of all of it, though.
09-08-2015, 08:10 PM
#73
Surging is tolerable over 1800 rpms, but the reversion or misfire when cruising at 75mph has become annoying, this is what LPE says is characteristic of the GT21. GM did some really good things on the new Z/28 that I am interested in, being 3.90 gears and the 5th 6th trans. gear ratio change. I would like to keep the GT21 since it pulls so hard to 7000!
09-08-2015, 08:25 PM
#74
Pro
Thread Starter
Surging is tolerable over 1800 rpms, but the reversion or misfire when cruising at 75mph has become annoying, this is what LPE says is characteristic of the GT21. GM did some really good things on the new Z/28 that I am interested in, being 3.90 gears and the 5th 6th trans. gear ratio change. I would like to keep the GT21 since it pulls so hard to 7000!
Maybe we drive differently but I don't have any of the surging issues unless I am trying to lug it around. With the 3.90 gears I can now short shift like I would a stock Vette with no issues. It's only at part throttle or off throttle that gives me a slight cam surge. The gearing and tune have really changed the drive ability of my car.
09-08-2015, 09:04 PM
#75
What year is your Vette? I assume you have the long tube headers and full exhaust? Do you run 91 or 93 octane where you are? I am running a 93 octane tune.
Maybe we drive differently but I don't have any of the surging issues unless I am trying to lug it around. With the 3.90 gears I can now short shift like I would a stock Vette with no issues. It's only at part throttle or off throttle that gives me a slight cam surge. The gearing and tune have really changed the drive ability of my car.
Maybe we drive differently but I don't have any of the surging issues unless I am trying to lug it around. With the 3.90 gears I can now short shift like I would a stock Vette with no issues. It's only at part throttle or off throttle that gives me a slight cam surge. The gearing and tune have really changed the drive ability of my car.
09-08-2015, 09:09 PM
#76
Pro
Thread Starter
Car is 2009: I do run 93 as well. full long tubes and corsa exhaust. I was recently at LPE for a retune after a set of new O2 sensors. Brent from LPE made multiple changes and dyno pulls to 580 rwhp He said it behaves like all the other GT21 cars? I maybe asking too much, but the exhaust reversion gets old on the highway. I'm after a well suited street, road course and drag strip car just via tire and wheel change. I can also, short shift just need to keep it above 1800 and most is good!
I can say that the difference in tune from LPE to my local tuner was night and day different. Perhaps you should seek out someone who is better able to tune?
09-09-2015, 03:17 PM
#77
Pro
Thread Starter
Found this article and thought it was relevant to this discussion about the RPM diff.
http://www.streetlegaltv.com/tech-st...ports-and-rpm/
http://www.streetlegaltv.com/tech-st...ports-and-rpm/
Last edited by Nick996; 09-10-2015 at 07:49 AM.
09-10-2015, 09:55 PM
#78
Found this article and thought it was relevant to this discussion about the RPM diff.
http://www.streetlegaltv.com/tech-st...ports-and-rpm/
http://www.streetlegaltv.com/tech-st...ports-and-rpm/
09-18-2015, 06:59 AM
#79
Pro
Thread Starter
Update - I did this and can repeat all day now. Once the clutch is out it will roll/run without any throttle input. No hesitation. No surge. No issues. That being said I did have the tune set with the idle to 1k RPM so it doesn't idle in the stock range which probably makes this test better.
09-18-2015, 04:12 PM
#80
Update - I did this and can repeat all day now. Once the clutch is out it will roll/run without any throttle input. No hesitation. No surge. No issues. That being said I did have the tune set with the idle to 1k RPM so it doesn't idle in the stock range which probably makes this test better.