taking out a lot of gear. want some opinions.
02-21-2010, 10:35 AM
#1
taking out a lot of gear. want some opinions. car is a street car. and its going to stay that way. so im taking some gear out. heres the circumstances to my decision.
1. degreed cam and it now peaks at 6100 vs 6400 before. so ill be dropping my shift point a few hundred rpm.
2. with the 4.10's i was over 7k crossing the traps on a 28x10 et drag, on the motor i was also over 7k on my 315/35r17 drag radials. after 6500 the car is starting to fall on its face.
3. i drive it several days a week and if an impromptu race arises the car shreds the tires in any mph in the first 2 gears and will spin them thru 3rd if i try and speed shift it. btw...this is on motor.
so my question is im going to a 3.54 gear. no one makes a 27" stiff sidewall tire that i have seen. (this is a 3800+lb 6 spd car) will a qtp quick time pro be sufficient tire for my combo?
and has anyone seen any noticeable loss in performance going with less gear? i know i am making some sacrifice somewhere but i dont want to kill it either. the car is making more power now then with the old combo and will be making even more on the spray so i will need to the extra mph anyways and a bigger tire is out of the question.
1. degreed cam and it now peaks at 6100 vs 6400 before. so ill be dropping my shift point a few hundred rpm.
2. with the 4.10's i was over 7k crossing the traps on a 28x10 et drag, on the motor i was also over 7k on my 315/35r17 drag radials. after 6500 the car is starting to fall on its face.
3. i drive it several days a week and if an impromptu race arises the car shreds the tires in any mph in the first 2 gears and will spin them thru 3rd if i try and speed shift it. btw...this is on motor.
so my question is im going to a 3.54 gear. no one makes a 27" stiff sidewall tire that i have seen. (this is a 3800+lb 6 spd car) will a qtp quick time pro be sufficient tire for my combo?
and has anyone seen any noticeable loss in performance going with less gear? i know i am making some sacrifice somewhere but i dont want to kill it either. the car is making more power now then with the old combo and will be making even more on the spray so i will need to the extra mph anyways and a bigger tire is out of the question.
02-21-2010, 06:37 PM
#3
I like your thinking of paying attention to your rpms and where your car falls off, so with that thinking in mind don't forget you will have to get the rpms up in the beginning of the run to get to the bottom end of where she starts to make power as well so you have this balance of having to get the motor up and get the car moving out as well as staying in your ideal rpm range and not go over it too much at the end of you pass.
I don't really understand why you would drop your gear and at the same time going to a smaller tire, I'm sure there's a calculation of some kind that you could predict your trap rpm making those changes.
I personally think going to a shorter tire is a mistake for obvious reasons.
If it were me I would stick with the 28's and just drop the gear a little bit.
3:73's is most likley what I would go with and IMO that should be your only change at this point. I think 3:54's are a mistake with your combo and 27" shoes an even bigger mistake.
I don't really understand why you would drop your gear and at the same time going to a smaller tire, I'm sure there's a calculation of some kind that you could predict your trap rpm making those changes.
I personally think going to a shorter tire is a mistake for obvious reasons.
If it were me I would stick with the 28's and just drop the gear a little bit.
3:73's is most likley what I would go with and IMO that should be your only change at this point. I think 3:54's are a mistake with your combo and 27" shoes an even bigger mistake.
02-21-2010, 06:48 PM
#5
I like your thinking of paying attention to your rpms and where your car falls off, so with that thinking in mind don't forget you will have to get the rpms up in the beginning of the run to get to the bottom end of where she starts to make power as well so you have this balance of having to get the motor up and get the car moving out as well as staying in your ideal rpm range and not go over it too much at the end of you pass.
I don't really understand why you would drop your gear and at the same time going to a smaller tire, I'm sure there's a calculation of some kind that you could predict your trap rpm making those changes.
I personally think going to a shorter tire is a mistake for obvious reasons.
If it were me I would stick with the 28's and just drop the gear a little bit.
3:73's is most likley what I would go with and IMO that should be your only change at this point. I think 3:54's are a mistake with your combo and 27" shoes an even bigger mistake.
I don't really understand why you would drop your gear and at the same time going to a smaller tire, I'm sure there's a calculation of some kind that you could predict your trap rpm making those changes.
I personally think going to a shorter tire is a mistake for obvious reasons.
If it were me I would stick with the 28's and just drop the gear a little bit.
3:73's is most likley what I would go with and IMO that should be your only change at this point. I think 3:54's are a mistake with your combo and 27" shoes an even bigger mistake.
as far as launching the car is making a **** ton more torque now in the mid range (picked up over 30hp/ 30tq at 3500) and i leave on the 2 step. which can be set wherever it need be.
02-22-2010, 07:06 AM
#6
I hear ya on the street thing, but you said you want it to work and I think you'd be hard pressed to find an f body running your #'s with a 27" tire, not saying it's impossible but certainly not ideal (for the track).
As far as the gear/street thing, IMO-you have an M6-stop it already.
I know a guy that drive's his M6 from NJ to South Carolina with his NA Trans Am with 4:56 gears, cruises the shore in the summertime as well.
You got 6 gears bro', use 'em!
As far as the gear/street thing, IMO-you have an M6-stop it already.
I know a guy that drive's his M6 from NJ to South Carolina with his NA Trans Am with 4:56 gears, cruises the shore in the summertime as well.
You got 6 gears bro', use 'em!
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02-22-2010, 09:47 AM
#9
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my ets were on average, the same with the 3.73s as with the 4.11s. My mph dropped by 1 or 2. Problem is i never got a run in with really good track prep. I am doing more suspension stuff this year to hook more consistantly on inconsistant track. I might put the 3.73s in just to see what they do after everything is nailed down with the 4.11s. I do like the 4.11s for cruising around town in 4th though.
02-22-2010, 11:18 AM
#10
With the 6 speed, there's absolutely ZERO reason to decrease the rear end ratio other then ruining the track performance.
If it's just barely getting out of the power range like you say, then o.k. maybe it "might" pick up of you go to a 3.73, but that's the absolute highest I'd go to, the rpm difference isn't gonna be that much, and with the 6th gear on the street, there's no reason to even need to get away from the 4.10.
You have a built motor.. spin it to 7500 if you have to. And if it's otu of steam too early, I'd be changing the cam and getting it to pull to 7200 before I'd be changing the gear and killing the track performance.
As for the tire, yeah you "can" get a smaller tire to work, say a 27 or 26 inch tire, but why? If you already have the room for a 28, leave it on there.. the consistancey you get from the bigger tire is well worth it. If you don't like street driving with the smaller tire, get a taller tire to street drive with.
I have a buddy of mine with a fox body and a 351, granted this is a different monster but he's got an old school ford 4 speed in that with 4.88 gears, and rolls on a 28 inch tire on the street. That, I call excessive, it's screaming all the time.
But 4.10's with a .5 to 1 overdrive? Come on man it's not that bad LOL.
If it's just barely getting out of the power range like you say, then o.k. maybe it "might" pick up of you go to a 3.73, but that's the absolute highest I'd go to, the rpm difference isn't gonna be that much, and with the 6th gear on the street, there's no reason to even need to get away from the 4.10.
You have a built motor.. spin it to 7500 if you have to. And if it's otu of steam too early, I'd be changing the cam and getting it to pull to 7200 before I'd be changing the gear and killing the track performance.
As for the tire, yeah you "can" get a smaller tire to work, say a 27 or 26 inch tire, but why? If you already have the room for a 28, leave it on there.. the consistancey you get from the bigger tire is well worth it. If you don't like street driving with the smaller tire, get a taller tire to street drive with.
I have a buddy of mine with a fox body and a 351, granted this is a different monster but he's got an old school ford 4 speed in that with 4.88 gears, and rolls on a 28 inch tire on the street. That, I call excessive, it's screaming all the time.
But 4.10's with a .5 to 1 overdrive? Come on man it's not that bad LOL.
02-22-2010, 10:15 PM
#11
well the 4.10's are coming out. im not changing the cam. i just had it out 3 wks ago. im actually buying some hoosier 275/60's for an impromptu race this wknd so im going to try and make it work on those. and i do use all 6 gears. everyday. id like to use 5 
and there really isnt any decent street tire to my liking taller then what i have now. not without buying some 16x10's.
and there really isnt any decent street tire to my liking taller then what i have now. not without buying some 16x10's.
02-23-2010, 04:37 AM
#13
You can take the 4.10's out, but I already know what that will do, it's gonna make the car leave like **** and fall on it's face. Even with the smaller tire, it's still gonna happen, and then you run the risk of a nitrous backfire.
But do what you want.... you have a 9 second car that you can drive as it is, I'd learn to live with that, trust me. It's a big accomplishment, having the car still drivable, doing anything to take performance away, I wouldn't do it. Unless you can live with the car going from 9.8 back to 10.x... I wouldn't do it.
Get a 2nd set of rear rims and roll on that 275 radial on the street, then you have essentially a 3.73 for the street, which is still plenty livable.
But do what you want.... you have a 9 second car that you can drive as it is, I'd learn to live with that, trust me. It's a big accomplishment, having the car still drivable, doing anything to take performance away, I wouldn't do it. Unless you can live with the car going from 9.8 back to 10.x... I wouldn't do it.
Get a 2nd set of rear rims and roll on that 275 radial on the street, then you have essentially a 3.73 for the street, which is still plenty livable.
02-23-2010, 06:37 AM
#14
Hey man, what street tires do you use? what rims?
FWIW, I use the MT Sportmans, the smallest one is 29" tall, that's the one I use for my street driving. That'll take some gear out for ya.
FWIW, I use the MT Sportmans, the smallest one is 29" tall, that's the one I use for my street driving. That'll take some gear out for ya.
02-23-2010, 09:45 PM
#18
that was my plan before greg weld went belly up. they had a 17x9.5 coming out i would run up front and then 15x10 in the back. noooow that nitto has a 315/40r18 out its 28" tall but i will need to buy 18" rims. either way its in the air as far as street wheels go. but i really need more mph on the street and the track then what my current combo provides. so maybe a 28" and a 3.73.
