What will happen to 1/4 mph after gear swap?
#1
12 Second Club
Thread Starter
iTrader: (14)
Join Date: Jun 2007
Location: Renton, WA
Posts: 2,563
Likes: 0
Received 0 Likes
on
0 Posts
What will happen to 1/4 mph after gear swap?
This is a non F-body question
Hoping you guy's can help me figure out what will happen to my finishing 1/4 mph.
I swapped the gear ratio in my GXP, and went from a 2.93 to a 3.69
Last year I crossed the line doing 12.7's@110ish toping 2nd gear (6500-6800)
I shift at 6500rpm, and my car really comes on hard after 5000rpm, so I am a little worried about 3rd gear.
Trans ratios are:
1st 2.92
2nd 1.56
3rd 1.1
3.69 finial drive w/26" tire
Will I trap 110mph at 5200-5300rpm? Or will I trap less now, since 3rd will have to recover from 4500-4600 rpm after the shift? My 1/8th mile mph was 87mph last year and this is where the trans shifts into 3rd now. I can't see a 22mph gain in 600-700rpm.
Yes it's a FWD... I already know
Hoping you guy's can help me figure out what will happen to my finishing 1/4 mph.
I swapped the gear ratio in my GXP, and went from a 2.93 to a 3.69
Last year I crossed the line doing 12.7's@110ish toping 2nd gear (6500-6800)
I shift at 6500rpm, and my car really comes on hard after 5000rpm, so I am a little worried about 3rd gear.
Trans ratios are:
1st 2.92
2nd 1.56
3rd 1.1
3.69 finial drive w/26" tire
Will I trap 110mph at 5200-5300rpm? Or will I trap less now, since 3rd will have to recover from 4500-4600 rpm after the shift? My 1/8th mile mph was 87mph last year and this is where the trans shifts into 3rd now. I can't see a 22mph gain in 600-700rpm.
Yes it's a FWD... I already know
#2
I can't really help bc I'm not a calculator kinda guy but I can't see I hurting the ET or the MPH, but in the end does it matter if you ET quicker what the MPH is? By the way, where do you race at? I lived up there about 10 years ago.
#5
12 Second Club
Thread Starter
iTrader: (14)
Join Date: Jun 2007
Location: Renton, WA
Posts: 2,563
Likes: 0
Received 0 Likes
on
0 Posts
Yes, its street driven.
The gears have made a huge difference when accelerating. 3rd gear feels a little weak until 5000rpm.
5.3 with pat g cam, ls6 p&p heads, ls6 intake, headers, and 3" exhaust.
I haven't made any new passes with the upgraded heads and gears yet though. Hopefully in a week or two.
Best et was 12.71@109.98
1.9 60ft last may
The gears have made a huge difference when accelerating. 3rd gear feels a little weak until 5000rpm.
5.3 with pat g cam, ls6 p&p heads, ls6 intake, headers, and 3" exhaust.
I haven't made any new passes with the upgraded heads and gears yet though. Hopefully in a week or two.
Best et was 12.71@109.98
1.9 60ft last may
Trending Topics
#8
11 Second Club
iTrader: (13)
you have to account for RPM lost with shifting. You won't drop to the exact RPM through gear changes because you lose speed when you shift. The RPM will be lower than 5200 because of this.
Ideally you want to set up your gearing so that you are crossing the line just after power peaks. This can make the car a little less than fun to drive if it's a daily driver though.
Ideally you want to set up your gearing so that you are crossing the line just after power peaks. This can make the car a little less than fun to drive if it's a daily driver though.
#9
12 Second Club
Thread Starter
iTrader: (14)
Join Date: Jun 2007
Location: Renton, WA
Posts: 2,563
Likes: 0
Received 0 Likes
on
0 Posts
Went racing last Friday, and trapped 110.58 and 110.2's all night long. So I am happy to report that I didn't loose any speed. My 1/8th mile mph is now 88.8 so I picked up a full mph.
Traction was horrible, so I was only getting 2.2-21 60 ft. I was still running low 12.9's though...
Traction was horrible, so I was only getting 2.2-21 60 ft. I was still running low 12.9's though...
#10
12 Second Club
Thread Starter
iTrader: (14)
Join Date: Jun 2007
Location: Renton, WA
Posts: 2,563
Likes: 0
Received 0 Likes
on
0 Posts
I was dyno'd last week and put down 349@6000 hp and 334@4900 tq
https://ls1tech.com/forums/ls4-perfo...g-day-vid.html