fasttagurl

iTrader: (12)

I'm trying to see if the issue lies within the tune or the transmission. In the 1/4 mile, I have to run my car in drive or it will run out of gear if left in 3rd. (4L60E) I know I can get better times out of the car in the 1/4 if I can get it to run the same ET in Drive as in 3rd gear. Any thoughts?

Example:
1/8 mile run in 3rd: 6.53 with 1.41 60"
1/4 mile run in Drive: 10.57/6.75 () with 1.54 60"

We obviously had some traction issues with the 60" but it felt like it hooked to me; or maybe the car is programmed to be slower in drive? But the overall shift points are the same no matter what gear I race in.

dlove

iTrader: (23)

The trans gets more pressure in 3/D. "Drive" for you is really overdrive. In Camaros it is labeled OD - D - 2 - 1, so some might get confused.

I would go a different gear or tire size. Maybe even bump the rev limiter. You really don't want to go into 4th/OD down the track. If you need to, I would be in 3 till you get half way down the track and then bump it up to D.

fasttagurl

iTrader: (12)

I run a 28" tire now, would going to a 30" slow my times in the 1/8 mile? I run this weekly but still need to make 1/4 mile with good ET's once in a while. I was thinking about manually shifting it from 3rd to Drive at 3/4 of the way through the 1/4 but was worried about the inconsistancy of it. (I'm a bracket racer.) Thank you, you are EXTREMELY helpful.

dlove

iTrader: (23)

your best bet would be to raise the rev limiter, depending on how high you are already spining it. Although if at 3/4 track you up shift, it won't shift till it actually hits the trans paramaters for a WOT shift, RPM and MPH. Staying in third would be faster if you can do it.

30's would slow you down. If the 28'' is working (it looks to be) I would stick with that. You want to run the smallest tire your car will allow.

fasttagurl

iTrader: (12)

This is what I thought, and makes sense. I found that even if I set the shift points around 6100 (at the top of my cam's powerband) it never shifts right at 6100, it waits for the MPH entered in the PCM and shifts from there. I have not raised the shift points since the car would fall off it's powerband. I am going to see how long it will stay in 3rd before hitting the limiter at what RPM, then on the next pass I'll shift it into 4th up top. I know I have to use overdrive to make it through without changing gear. My gears match with my set-up really well, and I would hate to change them just for the 1/4.

Your set-up is interesting; Would you mind telling me what #'s you run? Thanks again for the wealth of knowledge.

dlove

iTrader: (23)

I hope to find out this weekend. The goal is 9's N/A

went mid/low 10's N/A last year with the LS2/cam only and less gear 3.73's (left about 20-30 mph in rpm range) and more weight (100-150lbs). The car has a glide so it is very dependent on the correct gear. I feel it was really hurting me.

This year is the LS3, 4.11's and lots of other goodies. Check my build thread in the staff vehicle section for more.

thanks!

What size cam do you have? 6100 seems kinda low. I shift my car at 7300, any less and it slows down.

fasttagurl

iTrader: (12)

224/232, .631, powerband on cam card says max 6250, I told Crane I wanted a cam with lots of power low-to-mid range, so I could pull away from them at the line!

dmart

iTrader: (3)

I was always told to shift 300-500 rpm past your peak power. I have a similar cam and I shift at about 6600.

daniel6718

iTrader: (36)

just go into od...wont hurt anything...you could plan on that and run even more gear

fasttagurl

iTrader: (12)

I know it doesn't hurt anything except my ET's, which is a big deal to me. Like I said, my gear matches the car perfectly for the 1/8 mile, the majority of the races I attend.

fasttagurl

iTrader: (12)

I tried much higher shift points, and the car falls on its face and runs 11's. Everyone's cam will have a different powerband unless they have the exact same cam/maker. I've never been successful with this cam shifting above the 6100.

dlove

iTrader: (23)

If you have access to a tuner. I would just up the shift points in 3rd (along with rev limiter). Maybe even play with the other gears and see what works. I bet you have enough power up to 6400-6500 (stock rod bolt safe limit) to not require another shift. I know with comp, the cam description (not the specs) are just computer generated and they don't always test them. Thus, it might make power higher than they say.



edit: maybe not. lol

dmart

iTrader: (3)

Oh I didn't realize you had tried it. I'm surprised that cam makes power so low.

fasttagurl

iTrader: (12)

1.41 60" pretty good!

dmart

iTrader: (3)

Wish my stick car could cut short times like that.

5.3LJimmy

iTrader: (10)

What gear are you running, where is your rev limiter set, and what MPH in the 1/4?

fasttagurl

iTrader: (12)

4.56, not sure (where do I find this?), 125.88

Sunset'01Z

iTrader: (10)

gears are too low.. you dont need to be going into 4th in the 1/4.

5.3LJimmy

iTrader: (10)

The rev limiter is set in the tune. You should be able to cross the traps at 126MPH close to 7000RPM depending on the amount of converter slip you have. I would push the rev limiter up to 7200 and set the shift point for 3-4 @ 135MPH to stop it from shifting into overdrive. What bottom end/shortblock setup are you running?

5.3LJimmy

iTrader: (10)

If she is running mostly 1/8 mile then she should keep the 4.56's. If she has a bottom end that can take it there's no reason she can't cross at 7000RPM with her setup. A little shift point and rev limiter tuning seems like the better option to me.