Transfer gears or ring/pinion?

[Reeves]

I'm driving my van every day now (now that I have most of the bugs worked out), but I really want some taller gears.

I think when I first got it, it had 75 series tires on it that were shot, so I put on a set of used 245/50/15's that I had on my Shelby Z. Looks alright, rides alright, but the rpm's went skyrocketing at my cruise speed (about 65-70mph).

Is there a set of transfer gears I can get and change, or do I need to look for a different tranny with a different ring/pinion combo?

I NEED good gas mileage!

I'm also thinking of getting 235/60/15's for it... ??

[turbovanman²]

I ran taller tires on my van and honestly, my mpg didn't change. I guess it depends on how much of a drop you have, IE 5-600 rpm would probably be huge. I was running P215/65R15's and before 60 series, theres about an 1/2-3/4inch difference. It changed the RPM 2-300. I am now running P225/55R16's, there aprox 1/2-3/4 inch shorter and I am getting better fuel economy??????? Guess it puts me into the powerband faster and around town, easier on the loud pedal.

You can swap in a set of .91 transfer gears, thats the next step for lower gear ratio over the stockers.

[Lugert]

Don't bother with the .91 gears.

[turbovanman²]

Don't bother with the .91 gears.

Why? I used them but I don't have back to back info as the built TC I had was bad so I swapped out gears thinking it was them.

[Lugert]

Mileage did not change when not towing.
When towing it went down 4 mpg.

[GLHSKEN]

Could James issue be a worn out tq convertor robbing his mileage??

[Lugert]

What were the RPM's at 70 MPH?

[GLHSKEN]

He told me about 4k

[Lugert]

That is a little high, not too bad.
I remember the .91 gears lowered my RPM's by about 500 rpm, but it put too much of a load on the turbo and was up in boost creating more fuel delivery.

With a bigger than stock turbo it may be better.

[turbovanman²]

Mileage did not change when not towing.
When towing it went down 4 mpg.

That would make sense, more load on engine to keep same mph, thanks!


Stock gearing, 120 km/h, P215/65R15 tires, around 36-3800 rpm, P225/55R16's, 37-3900rpm.

[Reeves]

Lugert, you still have the .91 gearset? Also, is that a diesel in that avatar?

Another question I have. The transmission in this van has the connector for TC lockup. Can you use a TC lockup trans without a lockup convertor, or do you think someone swapped in a later trans (lockup) along with the lockup convertor? Can I apply 12V to this connector to find out? Maybe I can mount a convertor lockup toggle switch on the dash for my 100 mile roundtrip to work?

I don't tow with the van, and if I do, it'll be very rare. It's just my daily beater.

[turbovanman²]

You can't run a lockup converter on a non-lockup trans and vice versa, you need to swap out the input shaft.

Yep, hook one side to ground, one to power and see what happens. Make sure your moving and turn it on, you should see and watch the RPM's drop 2-300 rpm. Just to make sure, start to slow down and it should act like 5 speed if you don't disengage the clutch.

[87csx2.4]

Can I apply 12V to this connector to find out? Maybe I can mount a convertor lockup toggle switch on the dash for my 100 mile roundtrip to work?

Thats what a friend of mine did with a 700r gm trans in his 68 pickup worked great.

[Reeves]

You can't run a lockup converter on a non-lockup trans and vice versa, you need to swap out the input shaft.

I was hoping you would say that!! Wow, I hope this works. I might keep the high rpm gears and then just lock it up.

The TurboDiesel guys use a lockup switch a lot to control braking and you can turn in on after 15mph for some GRUUNNT while on the LOUD pedal!! Just don't forget to turn it off before you stop.....

[Stevien1]

I'm running the .91 transfer gears in my turbovan (2.60 f/d) with regular 195/75R14s. According to the scanner- 2800rpm @ 75mph, which is great for keeping the big exhaust tolerable on long trips. However, I sometimes miss being able to fry the tires through 1st and chirp 2nd.....

-Chuck James

[turbovanman²]

WARNING-don't WOT or load up the engine with boost when you have the TCC turned on, its not strong enough and you'll destroy the friction material inside the converter.

I was on the freeway tonight and with my 16inch tires, I was 3000ish at 60mph and 3400ish and 70 mph. Hope this helps.

I would say get the .91 gears also.

[87csx2.4]

Pats converters is working with racersteve on a lockup converter with kevlar disc he is locking up the converter on his 500 plus horsepower neon.So far so good from what I understand.

[87csx2.4]

Here ya go.http://www.tciauto.com/instructions/376600_inst.htm

[TurboJerry]

The LU only works in 3rd gear. It can hold the power as long as you don't engage the LU under power. There is ways to firm up the LU so it won't slip which means it can be engaged under power if done right(Kevlar or not). My Spirit has LU and it gives about 3 to 4 mpg better. I get 29 mpg if I drive *fairly* normal. It drops about 400 to 500 rpm. I use the standard T-gears.(1.06).

[turbovanman²]

Wow, another old thread back. I have been talking with Frank alot about this and after drag racing is over, going to swap to the .91 gears, fuel ecomony needs to improve and the 16v won't happen until spring of next year.