gear choices for cobra

jaysvt

jaysvt

Forum Member
What gear should i run in a 1998 cobra with a vortech blower.... 4:10 or 3:73?

im looking for the best time at the track but still be streetable too. its not my daily driver.

thanks
jay
 
soap said:
That doesn't matter.

OP.....pick you gear according to what height tire you run and what MPH you run.

--Joe
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it matters how much power the car makes becuase it could run out of gear.

tire hieght matter sbut if its a typical cobra most like a 275 40 17
 
Sean said:
it matters how much power the car makes becuase it could run out of gear.
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Correct.....how much power he makes, which will relate to what trap speed he runs (like I asked).

How much boost he runs is irrelevant, since it is not directly related to power.

--Joe
 
I would go with the 3.73 or even the 3.55...especially if it is a street car. If you have the car set up for 1/4 mile at a time only, then it would be worth calculating it all out for the absolute correct gear for that amount of distance.
 
you guys need to keep in mind, this isn't a pd blower car. IMO 4:10's - 4:30's I ran 4:10's on my vortech 6 speed car and it wasn't enough low end power, switched to 4;30's and got the low end I needed

3:55-3:73 the car will be a dog down low, but it all depends on boost level I was only running 10#'s on a stock lower end
 
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im running 8lbs of boost and a 305 35 r18 nitto drag. th tire height equals 26.4 inches. the car put down 425 on alternative's dyno. it has a 4:56 right now before i installed the blower

any info will help

thanks guys
 
jaysvt said:
im running 8lbs of boost and a 305 35 r18 nitto drag. th tire height equals 26.4 inches. the car put down 425 on alternative's dyno. it has a 4:56 right now before i installed the blower

any info will help

thanks guys
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Sounds like a good setup to me, leave it alone.

--Joe
 
4.56 might be a little short, as 4th will run out @ 120mph or so, and you should def be above that at the track.

I would say 3.73's if you plan on doing more mods, or are concerned with highway cruising.

If it were me I would go with 4.10's, they will keep you in the powerband and allow you to stay in 4th at the track.

You could just leave the 4.56's in and run a 28" slick at the track, which is probably easier than swapping gears. Traction on the street will probably be an issue though.

I had 3.55's in my SC'd Cobra and felt they were way too tall and fell into too low of rpms between shifts.
 
thats my problem now, the car just spins on the street. But it feels strong..... Its pulling around 3200rpm at 80mph on the freeway. I just feel im going to run out of gear by the end of the track, but i guess i need to bring it to the track and see.
 
jaysvt said:
thats my problem now, the car just spins on the street. But it feels strong..... Its pulling around 3200rpm at 80mph on the freeway. I just feel im going to run out of gear by the end of the track, but i guess i need to bring it to the track and see.
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Any high hp car just spins on the street. Go to the track and see what rpm you cross the traps, then adjust from there if necessary.

--Joe
 
jaysvt said:
im running 8lbs of boost and a 305 35 r18 nitto drag. th tire height equals 26.4 inches. the car put down 425 on alternative's dyno. it has a 4:56 right now before i installed the blower

any info will help

thanks guys
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My thougts are if you are planning on running alot of track events and want all the ET you can get a 4.10-4.30 sounds in the ball park. If your doing more street cruising and highway jogs a 3.90-4.10 might be a better choice but will sacrifice some ET at the track.
 
You are going to have issues getting any 18" tire to hook on the street. If you want to hook on the street you'll need more side wall and a better DR.
 
I have the EXACT same set up & hp,430's are to much on the street, all I did was spin the tires in first & then miss second gear. IF you can get the car to hook up 430's are very good for the track.
 
Rice Eatr said:
You are going to have issues getting any 18" tire to hook on the street. If you want to hook on the street you'll need more side wall and a better DR.
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my car hooked on the street just fine with a 18" tire and 4.10's, runs out of gear tho with the 4.10's

3.73's will probably end up in mine.
 
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