questions on drivabilty with gear swaps

lusiphur134 · Post by **lusiphur134** » Mon Aug 24, 2009 12:43 am

hi guys. my name is dave. this is my first post but i've been reading up for awhile. i've got a question on how the drivability is on using a dsm 4g63 with the different gearing when you swap gearboxs, specifically the toyo w58 gearboxs as thats what i have to use?

my project is actually building a Locost (Lotus 7 knock off). i plan on using the talon rear end which is 3.54 gears which is normally 4.9 in an awd i think. with the w58 gear box which is taller than a stock talon awd gearing too. the car is planned about 1500lbs curb weight. not planning on using it as a track car so i dont mind the less acceleration.

so should i worry about the gearing? am i going to be slipping the clutch to 2000 rpms to get a smooth takeoff or will it be like any other 4 cyl.?

thanks for any help or advice. i've got a million questions but i'll try to read up on old posts before i clog up the forum with reposts.

screemin eagle · Post by **screemin eagle** » Mon Aug 24, 2009 10:04 pm

i dont know about the w58 but the r154 needs more gear at 2600 at cruise im going roughly 70 mph. im gonna do 3:90 to help bring the engine back into a happy place. starting in first is more like 2nd. i wouldnt use the dsm rear they are not that strong and minimal parts are available.

lusiphur134 · Post by **lusiphur134** » Tue Aug 25, 2009 1:04 am

thats what i was wondering. the w58 is only hundredths off in every gear, not a real difference. do you kknow the gear ratio or tire size your running now?

as for the dsm rear being weak i've heard rumors but no real facts or numbers. it has about 115k nice miles on it and factory lsd. the other mainly used option for the Locosts are miata rears but that wont hold the 4g power any better than the dsm i dont think. plus i already have the dsm rear. the car is called a Locost(as in low-cost for a reason). i have been looking for a gutted supra for front and rear suspension and rear end but havent found one cheap yet

S0LJAH · Post by **S0LJAH** » Tue Aug 25, 2009 2:38 am

im running a d50 trans with a 4.3 rear at the moment and for me its a bit too rev happy

1st is almost non existent

hoping that the w58 i have here is going to sort it out a bit and maybe even need to go to a 4.1 or even a 3.9?

lusiphur134 · Post by **lusiphur134** » Tue Aug 25, 2009 12:28 pm

Soljah, i'm with you. i'm dont like rev happy quick shiftin setups either. i dont know the gears in a d50 so i can't compare to mine. my stock 4g starts waking up at about 2500 so i figure if i can get that to match to my usual cruising speed, i'll be in business. and i'm aiming on a 1500lbs curb weight so its not dragging around the 3000+lbs talon with power sapping awd. i figure that should help but never played with changing gears or masive weight so i'm just guessing

boise-nic · Post by **boise-nic** » Tue Aug 25, 2009 7:24 pm

Also keep in mind the turbo sizing. I plan to run only a 16G on my mightymax and think it would be more than enough. Being light weight you should scoot along well even off boost. I like the idea of having a small turbo (close to stock at least) with a big fat power band and tall gears. Suddenly those tall gears don't seem so tall if you can access boost and just use the torque band. I wish the mightmax had a bit taller gears but that can be fixed with a new rear diff and tire sizes.

Keep us posted on the locost. I was wanting to do something like that before I found this website

lusiphur134 · Post by **lusiphur134** » Wed Aug 26, 2009 2:01 am

just the stock 14b right now and wont go bigger than a 16g unless i would blow the $$$ on a stoker kit

but not likely to ever happen. i realize i can get smaller tires or even just downshift. i've never changed gears or had any big projects with this much customized options so its all trying to process. i do wonder what off boost will be like with so much less drivetrain and car to move.

i'll keep you guys posted on my progress. i should be getting the steel to make the frame in the next couple weeks. most people dont appreciate the 4g63 in anything other than an evo nowadays so i love the site and the variety of vehicles you guys conjure up

boise-nic · Post by **boise-nic** » Wed Aug 26, 2009 7:20 pm

lusiphur134 wrote: i do wonder what off boost will be like with so much less drivetrain and car to move.

If its freer to rev because you aren't hindered by a lot of weight, you should be able to get into boost pretty easily. What I'm saying is getting caught in the wrong gear wouldn't last for long with a car weighing 1500 lbs.

I would be wondering what on boost feels like. Here's a little comparo between a RWD 1500lb car and an AWD DSM...say both have 300hp

1500lbs / (300*0.85) = 5.88 lbs/hp
3200lbs / (300*0.76) = 14.03 lbs/hp

To get a DSM with the same hp/weight ratio it would have to have 544 hp. Ofcourse, you have to get that to the ground

DoubleJ · Post by **DoubleJ** » Wed Aug 26, 2009 9:02 pm

boise-nic wrote:
lusiphur134 wrote: i do wonder what off boost will be like with so much less drivetrain and car to move.
If its freer to rev because you aren't hindered by a lot of weight, you should be able to get into boost pretty easily. What I'm saying is getting caught in the wrong gear wouldn't last for long with a car weighing 1500 lbs.

I would be wondering what on boost feels like. Here's a little comparo between a RWD 1500lb car and an AWD DSM...say both have 300hp

1500lbs / (300*0.85) = 5.88 lbs/hp
3200lbs / (300*0.76) = 14.03 lbs/hp

To get a DSM with the same hp/weight ratio it would have to have 544 hp. Ofcourse, you have to get that to the ground

Now thats.... "food for thought" lol. Pretty interesting.

But like you said, gotta put that power to the ground.

lusiphur134 · Post by **lusiphur134** » Thu Aug 27, 2009 1:24 am

i ride a sportbike daily so i have a concept of what it'll be like but still some differences in the two.
the bike revs to 11k and is geared way tall(its a v twin so plenty of torque) and wheelies which i doubt the car will unfortunately

also traction not withstanding the driveline losses are a lot less without the awd system so measure at wheels and i don't need 300hp to compare to a stock awd's 300. only need 260-270. which a 4g makes if you sneeze at it.

i figure with the tall gears intial traction will be available and since i'm building chassis i can modify to fit 300 series slicks if i thought necessary. planning on the talons stock 205s on aftermarket rims. maybe size up to 225s.

boise-nic · Post by **boise-nic** » Mon Aug 31, 2009 7:31 pm

Yeah I figured 24% driveline loss for the talon and about 15% of RWD / FWD cars. I think FWD is less. Looks like fun. Post some pics when you start making some progress!

lusiphur134 · Post by **lusiphur134** » Wed Sep 02, 2009 1:01 am

25 for old awd and 15 for 2wd is my usual estamates. newer awds seem to get closer to 15 and 2wd down to 10 but thats based on manufactures numbers a lot and thats not the most reliable source.

and i'll try to get some pics up when i get rolling. going to deals gap weekend after next so planning on starting frame after that. it'll be a couple months before it'll look like a car.