215 tires + 300hp?

[stanhayward]

I daily drive this in the summer and like to give it a tame-ish thrashing pretty regularly. Would its get up and go be killed by a 2.93? I could look for a 3.25 instead. Tires are ultra-high performance summers

[fronton]

I have 300+ hp and was bummed at how much acceleration was lost going from 4.1 to 3.73. I am now looking for 3.91. I would never consider less than the 3.73 unless I had a 6 speed with different gearing ratios.

[stanhayward]

I'd be looking at a 6-speed as I'm leaning towards an engine swap. I don't really want to lose the responsiveness of the 3.73 I have now but I really don't want to be spinning through the first 2-3 gears.

[LJ851]

I had a 3.7 liter M30 powered E30 with 270-280 at the engine (230 at the wheels) and a very meaty torque curve. It had older 205 50 15s on it and a 3.25 LSD.

I would choose gear ratio based more on RPM range at the power levels you are talking about.

I could not use full throttle in first, but could generally get second gear down in a straight line if it was warm out. Corners,wet, or cold would not allow second at WOT.

If i kept that car i would have put a 3.45 gear in or maybe a 3.73 and some decent 225 tires.

[deutschman]

Imaginary topic is imaginary

[sharky]

Ha, I run 215's on my car w/ a 2:93. 450whp, Its called sticky tires and throttle modulation. Race logic traction control helps too. You will be fine, I get traction in 4th :) if I bang on it

[TobyB]

Step 1- get horsepower.

Step 2- ?

Step 3- worry about final drive and tires...

t

[Todd Black 88]

That much? The engine just had everything replaced so should make about stock horsepower and then even just the MAF and chip are dyno proven by Miller Performance to add 16whp. Then I have the KAmotors carbon intake and Ireland Engineering Exhaust components. I find it hard to believe that all of that only added 12 horsepower at the crank.

Millers dyno is.........optimistic at best. According to thier dyno, my car, with just thier maf and tune, made 189hp and 168 ft/lbs at the wheels. That is basically the factory crank numbers, at the wheels now. Didn't feel that big of a difference.

https://millerperformancecars.com/video-gallery.html?task=play&id=6&sl=cats&layout=listview&start=10

[stanhayward]

Oh okay, guess I'm wrong. Thanks for letting me know!

[ak-]

Millers dyno is.........optimistic at best. According to thier dyno, my car, with just thier maf and tune, made 189hp and 168 ft/lbs at the wheels. That is basically the factory crank numbers, at the wheels now. Didn't feel that big of a difference.
https://millerperformancecars.com/vi...tview&start=10

Are you really bummed about that lol? You gained like 30whp or so.

Their physical Mustang dyno is now installed at Castro's and I'd say it's more of a heartbreak dyno rather optimistic.

[evandael]

I have 300+ hp and was bummed at how much acceleration was lost going from 4.1 to 3.73. I am now looking for 3.91. I would never consider less than the 3.73 unless I had a 6 speed with different gearing ratios.

if you're certain of your skills Dave, you could swap the 3.91 ring and pinion from any number of automatic e36 (323/325/328 i/is/ic from 1992-1998 ) differentials into your e30 LSD case.. or maybe ask Mark down at McB if he knows a good transmission builder.

area yards should have tons of those diffs in stock for relatively cheap.. most were non-LSD and therefore nearly useless.


OP, nothing's more important than tire (read; rubber compound) selection. increasing tread width doesn't do much for linear acceleration, but rather lateral acceleration. that said, i'd go for 215's at least on 9" wheels, and with 300hp, you'll just need to be mindful of your right foot.

also important.. install camber/toe adjusters on the rear subframe and make sure the subframe/diff/trailing arm bushings are in good condition, and replace as necessary. that work, plus stiffer springs, matched dampers, and a small (or no) rear swaybar will help in keeping the rear wheels on the ground and at the proper geometry for maximum traction.

personally i would get at least a 3.23 or 3.25. i don't get the point of gearing just to increase load for boost. gear for acceleration! and it's important to realize that most 150k+ mile 'LSD' do very little to limit slip.. look into replacing the internal clutches and plates so it actually locks up.

[eurotrash]

/\ was just thinking this. Doesnt matter if its a 205 or a 305 if youve got 4 deg of camber in the back and a 6" contact patch. I'd worry about getting your rear suspension setup to put power down and proper ratio before i'd worry about size. Ive got around 300-320'/ibs of torque with a 215/welded 4.10/zero camber corection on a lowered car right now and i can punch it hard in 3rd and break it lose. Id get weld on tabs and a proper dif before anything else.

[F34R]

Does not matter what his numbers are right now...he is my first order in my turbo manifold GB ;)

[stanhayward]

Does not matter what his numbers are right now...he is my first order in my turbo manifold GB ;)

And I can't wait to get her all set up with it!

[MR E30 325is]

I made over 300 hpz in my E30 when it had the Supercharged S52 in it.

Rolling on 195's because I was broke as fuck and they were what the car had.

Not nearly enough tire. By a long shot.

I dont think 215's would have been enough.

Upgrading to fender flares and 235/245 before I go turbo.