prism_kiter

hello there guys,
i just brought a tpis mini ram intake manifold to go on my 1991 6 speed vette.
i purchased a 1205 port size that can be port matched out to a 1206 if need be once i have brought my new aftermarkert heads early next year.
currently i have a 3.45 rear dana 44 ratio.
any way im looking to find out what ratio should i upgrade for more performance for street cruising/traffic light driving out of the 3.73,3.93 or 4.10 gears please ?
jim @ tpis said either 3.73 or no higer than 3.93 and he said with 4.10 gears ,first gear would be pretty much useless so im now down too 3.73 or 3.93 i guess.
any help/ideas please .
btw, jim has been very friendly/helful too me just r.e the other thread where some are complaining/bashing so to speak about tpis service!!!
thank you
tyson

TM-Z06

Do you have plans to do anything with the heads and cam?

prism_kiter

hello there tm-96ce,
sorry to mention
yes i plan to get some ported heads around the 195 -210 cc range!
also i have 1.6 comp roller rockers to go and i also have a comp cam hydraulic roller cam with 268 duration on intake,276 on exhaust
113 lobe seperation,rev range 1,800-5,800 rpm,
.570 lift intake,.565 lift exhaust @ 1.6 ratio specs that is and duration @ .50 though is 218 intake, 224 on exhaust side.
thanks

vader86

I would go with the 4.10s.

byebyeL98

I think 4.10s and the ZF are nice match.

prism_kiter

hello guys,
thanks for the replys.
but wont first gear be pretty much useless having 4.10 gears though ?
as stated by tpis comments !!!
thanks

byebyeL98

Not if you intend on going with the intake / cam / heads package you mentioned earlier. The 1800-5800 rpm range would be a nice match.

If you planned on keeping the engine completely stock, I'd still recommend 4.10s, but you would be out of first gear quickly . For street cruising, they're fun .

If you were looking for best 1/4 mile times, they would be too steep for that cam's rpm range; revs in 4th gear would be out of the power range before the finish line.

engle1147

Sounds like a fun project! Don't forget it depends on the size of your rear tires too. If your running a bigger diameter tires use deeper 4.10 gear - if your sticking to stock sizes go with the 3.73.

I have had 3 ratios on my car in the past 10 years. The stock gears (I don't remember what it was) were in the low 3s. Currently, I run a 3.73 gears on my relatively stock '89 L98 - 3.73 is all the gear I'll ever need. I get about 16mpg in city ~ 20 highway when driving conservatively. With more gear (4.10 ratio with corrected speedometer grears) mpg was around 14mpg city and 17 highway. The "felt like" it was faster in the low end speeds with the 4.10s but in reality 60' times were very similar to the 3.73s (on my setup).

If you don't care about the mpg go with the 4.10s!

good luck!

prism_kiter

hello again guys,
i am interested in trying to get a good 1/4 mile time actually as you stated but also some fun/seat of your pants performance.
how about i go 3.93 ,then half way between 3.73 and 4.10.
as yeah im into 1/4 but also want to have it rite for the cam i have .
but also i was trying to concern the talk i hear of the mini ram loosing some low end torque so to speak but as i have never driven a vette yet with a mini ram and have not installed my intake yet i wouldnt really know.
so i though a larger gear may help me in that deparment.
also tire size im running is 315x35x17"
thanks guys

LD85

I would go 3.93 if I did another MR

Vic'89

I am currently running 3.07's with my Miniram combo in a Dana 44.

The Miniram wants much more gear !

Vic

hippy

It does, the trick is to hold second get til about 85.

LD85

http://www.f-body.org/gears/

BADDUCK

At least 3.90

tequilaboy

I would think 3.90s would be a nice compromise.

This results in very similar overall ratios to my own 4+3 and 3.73 gears, which I'm very happy with (even with an SR ).

4th gear will be a little shorter however, but still be capable of 114 mph at 6000 rpm.

It should be nice gearing for general street, 0-60 mph or 100 kph runs, 1/8 mile, 1/4 mile and lower speed roadcourse work.

60 mph or 100 kph at the top of 2nd gear, 1/8 mile should trap in the top of 3rd gear, 1/4 mile near the top of 4th gear.

Note: Use 811 revs/mile for the gear calculator to get the correct values.

You may not want to push the L98 bottom end too much higher than 6000 rpm (depending upon additional mods, of course).

With 4.10s it may be necessary to over-rev in some situations in 4th gear, depending upon how fast the car is.

I vote for 3.90s.

prism_kiter

hello guys,
ok then, 3.90 or 3.93 ratio it will be then!

tyson