Shifting Question for 2G GSX's in the 12's

[SOADweskey]

I have my car consistantly running low 13's and I hope 12's will happen at my next outing in December. On my 13.2 pass I shifted at 7000 rpm and left it in third crossing the finish line bouncing off the 7500rpm rev. limiter. I made a run shifting at 6000rpm and finishing in fourth and mt E.T. was 13.4 and my trap speed went down from 101 to 99.

I want to know what you guys that are in the high 12's are doing shifting wise, especially if you have a 16G and similar setups to mine.

 

[2gGSX]

Get a dyno plot and figure out where you start to lose power, then adjust your shift point to either that RPM or a few hundred after that RPM. This will get you back into the fat part of your powerband, even if it causes you to shift earlier.

 

[SOADweskey]

In general, are the HP calculations from DSMlink accurate enough to use for that? I don't have the free cash for dyno time right now with holidays coming up.

 

[biglady112]

The best way to do it is to look at your log your speed with dsmlink. Figure out where it starts to level out in each gear. As in where the line increases less or starts to flatten out. You can email me a log and I can tell you what I would do. I have NEVER been a big fan of shifting early. As I always thought even though power is falling off, you still have boost to pull you through.

Starting this year where I really started to help others tune at the track more, we have since gone to shifting when the car stops accelerating. And wouldn't you know it, each car go much quicker. My thought was to keep less shifts in the run. Now that is no longer and issue.

[email protected]

Steven

 

[SOADweskey]

I appreciate the response and will send you some log files in a little bit. I have to get my laptop out of my car.

 

[CanadianTSi]

Shift right around 7k and definitely shift to 4th!

 

[SOADweskey]

My car doesn't quite have the power to make it to 4th properly shifting at 7k. I'm running about 18psi and I'm determined to make 12's happen on pump gas which in Ca. means 91 octane.

When I shift at 7k I'm pretty much at the end of the track when 3rd hits 7k so I usually just leave it in and cross the line at almost 7500. I think if I can get my tune sorted out and put down more power then I will be able to get through 3rd fast enough.

 

[turbolover10]

I'd shift right around 7k, I hit 12.7 on my first run but it was with 110

 

[SOADweskey]

Here is one of my log files if any of you guys want to check it out and see what you think. I think the knock that is showing up is form my knock sensor going bad. I don't think that it should be having a problem with knock at 10.5:1. I'm putting a new knock sensor in within the week and I hope it works out for me.

 

[biglady112]

I repsonded to an email he sent guys. There is so much left on the table with just tuning alone, he could knock down a low twelve at his current boost level. And a little better driving.

Email responded to.

Steven

 

[2gGSX]

I've never seen anyone have to add fuel in order to run 10.5:1. There's a lot of conflicting data here as well--your front O2 voltages match up well to the wideband, yet your estimated A/F ratio is way more rich than what the wideband reads. This is actually symptomatic of a leak somewhere after the MAS. Have you done a boost leak test?

 

[SOADweskey]

I did a boost leak test the day before that run and I didn't have any other than my 1G BOV leaking at about 18.5 psi (which is why I set my boost just below that), and my throttle body shaft seals leak a little but I am swapping in a rebuilt 1G throttle body before my next trip out.

And if it matters my MAS is un-hacked and I am running the K&N FIPK and my intake pipe is one of the e-bay hard pipes.

 

[CanadianTSi]

My car doesn't quite have the power to make it to 4th properly shifting at 7k. I'm running about 18psi and I'm determined to make 12's happen on pump gas which in Ca. means 91 octane.

When I shift at 7k I'm pretty much at the end of the track when 3rd hits 7k so I usually just leave it in and cross the line at almost 7500. I think if I can get my tune sorted out and put down more power then I will be able to get through 3rd fast enough.

The faster you get through 3rd the sooner the rev limiter will come therefore you will be bouncing off the limiter before the finish line which will slow you down.

I would shift the 3-4 somewhere around 65-6800 rpms. Just use the NLTS feature with DSMLink and the 3-4 can be incredibly quick and smooth.

 

[SOADweskey]

I have a quick question regarding NLTS and my knock sensor. I think it is a sign of my knock sensor needing to be replaced but I want some opinions.

When I use NLTS it always plays hell with my knock sensor and it causes me to go into my next gear with 9 degrees of timing or more pulled due to knock. And then that value decreases in steps throughout the gear untill I shift again and then it happens all over again.

I'm going to get a new knock sensor tomorrow to see if I can actually yse the NLTS but I wanted some other opinions just to see what some others thought.

 

[SOADweskey]

Well the knock sensor wasn't my problem with using NLTS as the problem still exists.

I guess the next thing I am going to go after is my motor mounts as they are 80,000 miles old and stock. I think that my engine may just be bouncing around to much when it hits the rev-limiter.

Do you guys have any other ideas as to why NLTS causes my knock sensor to pull 9deg of timing when with the same tune if I don't use it I get little to no knock?