First drive in turbo project: Change gears?
09-25-2016, 09:10 AM
#42
The rate of change of engine RPM is the factor here
Imagine you can hold the engine at 2000rpm and go WOT. And just hold it there at 2000rpm and let the motor load up. That is what an engine dyno can do, I advise anyone that hasn't seen it to go find some videos of this process. By allowing the rate of change of engine RPM = 0 you can reach "full boost" or at least find max potential torque at whatever RPM you want. (then adjust the tune and variables such as coolant temp to find different results)
in say, neutral, or first gear, there isn't enough time to wait and see what full torque is, the rate of change goes way up to some big number and the opportunity is gone. Numerically higher gears show you less and less rate of change which is why "turbo cars" seem to do better in those gear.
Also it can be used to blow the gate open without any boost pressure to find lowest/lower boost (less turbine action)
09-25-2016, 09:24 AM
#43
I 120% disagree with turbo stick cars wanting extra tall gears.
Gear the car for your intended useage - if thats the dragstrip, then you gear for finish line rpm to be same as shift rpm.
the available transmission gear ratios are going to be the problem.
Gear the car for your intended useage - if thats the dragstrip, then you gear for finish line rpm to be same as shift rpm.
the available transmission gear ratios are going to be the problem.
09-25-2016, 12:18 PM
#44
This^^ I don't know why it is so hard to grasp.
09-25-2016, 03:15 PM
#45
It's a street car so I will probably put in some taller gears (3.23, 3.08, etc) just because highway cruising blows the way it sits, now that I have. 10.5# spring I am seeing boost in the top of second, not enough to do anything but I'm trying to break in clutch per mcleods recommendation (500 miles) without really beating the **** out of it or power shifting....for now lol. but good info 3pedals I know you car is badass and well sorted out so I appreciate the info
09-25-2016, 04:14 PM
#46
lol, my stick combo was never fully sorted out, but I did get it to work reasonably well. A truely fast stick drag car is a tough nut to crack
edit: just reading back over your posts, If I were in your shoes I would NOT even consider the 2,73's you mension. however if this is not a drag car, then taller gears are certainly worth it. I might consider 3,42, or 3,55. Dont go any taller(smaller numbers) than 3,23, no matter what.
what turbo is this 76mm?, and what are the turbine specs?
edit: just reading back over your posts, If I were in your shoes I would NOT even consider the 2,73's you mension. however if this is not a drag car, then taller gears are certainly worth it. I might consider 3,42, or 3,55. Dont go any taller(smaller numbers) than 3,23, no matter what.
what turbo is this 76mm?, and what are the turbine specs?
Last edited by 3pedals; 09-25-2016 at 04:23 PM.
09-25-2016, 08:32 PM
#48
that will be a fun street car when you get it sorted out.
That turbine is small, so dont get greedy with boost.
Wait till you get a few miles on the clutch, and then find out what it does for boost in the lower gears. It sounds like your not getting on the throttle very hard while you break in that clutch, and if thats the case, your boost testing up to now is almost meaningless.
That turbine is small, so dont get greedy with boost.
Wait till you get a few miles on the clutch, and then find out what it does for boost in the lower gears. It sounds like your not getting on the throttle very hard while you break in that clutch, and if thats the case, your boost testing up to now is almost meaningless.
09-25-2016, 08:52 PM
#49
Yea definitely granny shifting it before redline, I'm just doing as much data logging as possible to make sure I don't go lean, I have to contact Fitech because sometimes I am good at 10.9-11.7 but other times it goes all the way up to 12.5 so that needs sorted, timing is pretty conservative too, I actually used your recommendation I saw on bullet...my goal is to just have 7-9psi all said and done...this is my first experience with a turbo so I have some idea of what's going on when I turbo my 98 z28 in the future
09-26-2016, 02:06 PM
#51
After going back and looking through all setting there is an accelerator setting both standard (cruise/tip in) as well as fast accel that deals with wide open throttle...saw some guys on turboforum upping this to cure stumble so its worth messing with
10-24-2016, 01:24 PM
#52
Just want to post an update instead of starting a whole new post in case someone searched this topic in the future. I just got done installing a TKO600 into my car with the same Sachs flywheel, McCleod clutch, and 3.73 rear gears. It's almost like a night and day difference as far as boost goes. After comparing my data logging from the 4 speed compared to some initial 5 speed testing not only am I building boost quicker but more total boost. With a 10# spring I was getting a max of around 8.1 with 4 speed whereas I am now seeing around 9.3 with the 5 speed. Also the closer gearing keeps me in boost between shifts. I'm gonna make a graph to show the differences. Full disclosure I also put on a fresh pair of 275/60/15 BF Radial T/As compared to the dry rotted ones that were on with the four speed so I am sure the increase in traction helped engine load.
Here is the gearing difference between the two boxes.
Super T10 3.42 2.28 1.46 1.00
TKO600 2.87 1.89 1.28 1.00 0.64
Here is the gearing difference between the two boxes.
Super T10 3.42 2.28 1.46 1.00
TKO600 2.87 1.89 1.28 1.00 0.64
Last edited by wildcamaro; 10-24-2016 at 02:28 PM.
10-24-2016, 02:24 PM
#53
Just want to post an update instead of starting a whole new post in case someone searched this topic in the future. I just got done installing a TKO600 into my car with the same Sachs flywheel, McCleod clutch, and 3.73 rear gears. It's almost like a night and day difference as far as boost goes. After comparing my data logging from the 4 speed compared to some initial 5 speed testing not only am I building boost quicker but more total boost. With a 10# spring I was getting a max of around 8.1 with 4 speed whereas I am now seeing around 9.3 with the 5 speed. Also the closer gearing keeps me in boost between shifts. I'm gonna make a graph to show the differences. Full disclosure I also put on a fresh pair of 275/60/15 BF Radial T/As compared to the dry rotted ones that were on with the four speed so I am sure the increased the traction helped engine load.
Here is the gearing difference between the two boxes.
Super T10 3.42 2.28 1.46 1.00
TKO600 2.87 1.89 1.28 1.00 0.64
Here is the gearing difference between the two boxes.
Super T10 3.42 2.28 1.46 1.00
TKO600 2.87 1.89 1.28 1.00 0.64
10-24-2016, 04:09 PM
#54
Just want to post an update instead of starting a whole new post in case someone searched this topic in the future. I just got done installing a TKO600 into my car with the same Sachs flywheel, McCleod clutch, and 3.73 rear gears. It's almost like a night and day difference as far as boost goes. After comparing my data logging from the 4 speed compared to some initial 5 speed testing not only am I building boost quicker but more total boost. With a 10# spring I was getting a max of around 8.1 with 4 speed whereas I am now seeing around 9.3 with the 5 speed. Also the closer gearing keeps me in boost between shifts. I'm gonna make a graph to show the differences. Full disclosure I also put on a fresh pair of 275/60/15 BF Radial T/As compared to the dry rotted ones that were on with the four speed so I am sure the increase in traction helped engine load.
Here is the gearing difference between the two boxes.
Super T10 3.42 2.28 1.46 1.00
TKO600 2.87 1.89 1.28 1.00 0.64
Here is the gearing difference between the two boxes.
Super T10 3.42 2.28 1.46 1.00
TKO600 2.87 1.89 1.28 1.00 0.64
10-24-2016, 04:25 PM
#55
10-24-2016, 04:45 PM
#56
I was getting full traction in both cases hence why I listed the difference in peak boost lower gear boost. Also this was initially a discussion of gearing so while I didn't swap rear gears I changed the drive ratio with the taller gears of the new trans, imagine that.
10-24-2016, 06:03 PM
#57
