your comments please on this setup

[steelgrey330ci]

Well boys

Car is 330ci 5 speed

Current setup is ASA 1 TM12 with headers and 9.5 psi also 3:15 diff

I will have the TM 15 put in and the cams , should I put the old gearing back in. (2:93 diff)

I've been thinking about this cause I'm worried that I will go throught the RPM band to fast. Go to a longer gear for the new setup.

Please let me know what your thoughts are on this.

Thanks

[GBX330ci]

Well boys

Car is 330ci 5 speed

Current setup is ASA 1 TM12 with headers and 9.5 psi also 3:15 diff

I will have the TM 15 put in and the cams , should I put the old gearing back in. (2:93 diff)

I've been thinking about this cause I'm worried that I will go throught the RPM band to fast. Go to a longer gear for the new setup.

Please let me know what your thoughts are on this.

Thanks

I have a 3.07, which i think is perfect! I think its more perference then anything else. Drive it for a little while and see what you think.

How much did the TM-15 run you? You get sw and inj's too?

[beanfree]

Well boys

Car is 330ci 5 speed

Current setup is ASA 1 TM12 with headers and 9.5 psi also 3:15 diff

I will have the TM 15 put in and the cams , should I put the old gearing back in. (2:93 diff)

I've been thinking about this cause I'm worried that I will go throught the RPM band to fast. Go to a longer gear for the new setup.

Please let me know what your thoughts are on this.

Thanks

I would think you would be traction limited with the 3.15 diff. I would go back to the 2.93 diff. Have you done a dyno yet? Please post the results.

[pei330ci]

I'd try it first, you may like it.

For comparison, I'm running a 3.46 LSD and I'm actually looking at going to a 3.91 possibly with an eventual power boost above what you'll have with the TM15.

[beanfree]

I'd try it first, you may like it.

For comparison, I'm running a 3.46 LSD and I'm actually looking at going to a 3.91 possibly with an eventual power boost above what you'll have with the TM15.

I remember your ride being supercharged but am not sure what stage you have. In any case, with the 3.46 lsd, are you traction limited in 1st and 2nd? I don't see the point in going to a higher ratio if you spin the wheels with the current ratio.

[pei330ci]

I remember your ride being supercharged but am not sure what stage you have. In any case, with the 3.46 lsd, are you traction limited in 1st and 2nd? I don't see the point in going to a higher ratio if you spin the wheels with the current ratio.

I'm N/A right now, but I'm building a pretty heavy nitrous setup.

The point of a higher gear ratio is more torque multiplication. For some reason, everyone focuses on losing traction in 1rst gear...and writes off the benifits of having more torque multiplication in every other gear after it.

From my experience, changing from a 2.93 to a 3.46 diff added 1 gear change in the 1/4 mile. So the comments about having to shift more, are only relevant if you are accelerating over 88 MPH. You will spend more time accelerating in 3rd and 4rth gear than 1rst and 2nd combined, which is exactly where you need better torque multiplication.

For everyone that's worried about losing traction in 1rst and 2nd gear:

Why mechanically try to cover up poor driving skills with a diff that offers less torque multiplication? Learn to drive, and take advantage of all the power your engine can deliver.

BTW, the 3.91 ratio was caculated using my estimated power/weight ratio and tire size. There is a specific reason for it, it's not just a guess.

[pei330ci]

Just to further illustrate my point, the graph below shows acceleration in Gs from a data logging setup on a drag car:

http://i36.photobucket.com/albums/e29/PEI330Ci/Car%20Project/shiftpoints.jpg

The "G" spikes are shift points.

Shifting isn't nessesarily a bad thing if you are quick.

[steelgrey330ci]

I'll let you guys know how things go once I put it in.

Thank you for your feedback

[pei330ci]

I hope to see that beast of yours at Mosport!!!