Manual Transmission

[Fast4Ward]

I have never seen or even heard of anyone doing such a swap and was curious if theres a turbo buick out there with 5/6 spd?

 

[GNguy]

there was a post on this a few days ago.......not a good idea on these cars. Someguy did it to a TTA and it was really slow because the turbo kept having to spool when he let off the gas.

 

[GNVYUS 1]

A few guys have but IMO its a total waste.

 

[CTX-SLPR]

G-body manual transmission stuff is really really hard to find as it is different than the generic stuff. If you went to a hydrallic clutch you could eliminate most of the linkage specific stuff. However the idea of putting a stick behind a turbo Buick will work, but you will accentuate turbo lag because unless you start playing tricks with an aftermarket computer you will not be able to really get the turbo to spool on the line because the turbo spools against load such as from a converter. Also everytime you shift the turbo will enter compressor surge as the booste gets trapped between the now closed throttle blades and the spinning turbo so it feeds back across the compressor blades both despooling the turbo and potentially damaging the bearings in it. A blow off or bypass valve would help solve this problem but you still would have the turbo spinning down with no exhauste to power it during shifts. There has also been concerns about the durability of such transmissions with the ability of the Turbo6 to make huge amounts of tourque at low rpms.
In my opinion, it would be a bad idea unless you had some reason you needed to be changing gears often such as in a ralley or autocross application or maybe topspeed racing at bonneville for the extra OD ratio of a 6-spd.

Just my comments,

 

[Rocketolds]

I have 4 speed (soon to be 5 speed) behind an 85 hotair engine, in my 72 skylark and I love it, the car is much quicker than the 350 buick that was in it.

 

[bbbad6]

My car

I am building an LC2 with a 6 speed this fall/winter.
I started 2 years ago and was sent to Iraq.
Compressor surge is not a problem, A blow-off valve,(that loud whoosh noise on imports) is the solution, it allows the turbo to keep spinning, and just vents it to the atmosphere. The initial boost is the main issue, but can be overcome.
I'll tell you that for me fabricating the clutch setup was hardest, using 3rd gen camaro pedals, etc. thats been modified to fit.
The turbo buick motor isn't really as unique as everyone thinks, it was ahead of its time as far as technology in 1986. Most imports use standard transmissions behind turbo motors and do just fine, the other example is diesel trucks, so the powerband can be compensated for and made to work.

 

[I eat Z06]

I am also interested in a 6mt swap. I have made that transition from doing the 1/4 mile to cross country rallys. So the extra top end from a six speed would be much more usefull to me than not having spool from a dig. I also am running pretty small tires (17" wheels) so traction from a dig is a problem for me with boost down low.

Nick

 

[Rocketolds]

I used a flywheel from a buick 350, BOP aluminum bell housing, 10.5" clutch, and a howe hydraulic TOB. Everything bolted right up with no problems. Currently the trans is a T10 with a 3.42 first gear. This winter I am changing to a TKO500.

 

[madhat]

I was digging around on this for a bit(plan on doing it one of these days when I have the money)
http://garage-scene.home.att.net/t5_install.htm
http://www.montecarloss.com/ls1montecarloss/
http://www.monte-list.nu/tech/fivespeed.shtml
http://maliburacing.com/forum/viewtopic.php?p=166059#166059
I havent looked at this stuff in a while and jsut posted some of the sites I saved for this....
From what I remember, using the 80's F-body brake cylinder and petals hooked up to the t-56 si how they did it. The crossmember doesnt even ahve to me changed. The only thing i havent found is a bell-housing that will mate the T-56 to the LC2....if someone finds that let me know!

 

[Rocketolds]

I am not sure of the spelling, but weir products makes a conversion bell housing as does McLeod

 

[madhat]

Ah ok...I think Mcleod was where I saw it

 

[broke1]

Make sure you also have DFI.No way in hell are you going to be able to trick the stock ecm when the clutch goes in.

 

[madhat]

could you explain please?

 

[elcamino383]

Keisler engineering could make a TKO 600 or T56 fit a GN. im getting there TKO600 5 speed kit for my car this winter. im sick of autos. i think it will be a lot of fun.

 

[BJM]

Make sure you also have DFI.No way in hell are you going to be able to trick the stock ecm when the clutch goes in.

I cannot think of a single problem that the ECM would cause. You will be in and out of PE mode during each shift since your foot comes off the throttle. I would be inclined to put the blow off valve exhaust blast back into the MAF pipe or the lost air will result in the car running very rich while the blow off is venting. Most factory set ups do this. Otherwise the MAF reading will be high yet you are spilling off much of the air.

As far as PE mode is concerned, since our ECMs tend to be set for a fairly high threshold, you might need to change PE mode trigger points down a little to prevent the occasional knock as you get back into the gas and the mixture is briefly at stoich. One example is the Extender chip whose PE threshold is very low already.

Another issue with the factory LC2 is that the MAF is so far from the throttle body. If you are using a newer MAF with a translator and have the MAF right on the end of the throttle body you will wake up the driveability tremendously. There are several guys on here running like that all the time and it works really well. Just don't do what one guy did and explode the factory plastic MAF!

Another issue is the lack of 3rd and 4th gear switches that normally tell the ECM that the car is in upper gears. You could rig them up to the shifter for any gear above second. The reason you would want to think about this is that car will not otherwise pull boost in the upper gears as you would probably want it to do (however slightly). Also in 4th gear the car will enter highway mode if the switches are working and this will add a little timing while cruising and help gas mileage. Any chip with a lean cruise feature also needs these switches working properly. If you do not hook them up the car will always think you are in low gear. The other thing you might need is the P/N switch. I cannot think off hand what might not work correctly if you drive around while the car thinks you are in Park but it might give you a VSS code.

 

[broke1]

I cannot think of a single problem that the ECM would cause. You will be in and out of PE mode during each shift since your foot comes off the throttle. I would be inclined to put the blow off valve exhaust blast back into the MAF pipe or the lost air will result in the car running very rich while the blow off is venting. Most factory set ups do this. Otherwise the MAF reading will be high yet you are spilling off much of the air.

As far as PE mode is concerned, since our ECMs tend to be set for a fairly high threshold, you might need to change PE mode trigger points down a little to prevent the occasional knock as you get back into the gas and the mixture is briefly at stoich. One example is the Extender chip whose PE threshold is very low already.

Another issue with the factory LC2 is that the MAF is so far from the throttle body. If you are using a newer MAF with a translator and have the MAF right on the end of the throttle body you will wake up the driveability tremendously. There are several guys on here running like that all the time and it works really well. Just don't do what one guy did and explode the factory plastic MAF!

The factory ecm was never meant to handle a manual app(30 lbs off the back of the engine)

Do a search,gnvair has done the swap and swears its a waste of time.I beleive him...

 

[BJM]

The factory ecm was never meant to handle a manual app(30 lbs off the back of the engine)

Do a search,gnvair has done the swap and swears its a waste of time.I beleive him...

I do not understand your statement. While I believe someone might not like how it drives, what could the transmission weight possibly matter.

My post was trying to offer the guy suggestions, not simply tell him to give up.

One huge benefit of the auto is maintaining boost while shifting, unlike a manual but the manual done right would be lots of fun.

 

[madhat]

I just read some of the posts and gnvair mentioned that the car would stumble in idle and slowing down if the clutch were in....how many of you have ever put your car in neutral at the light? I definately saw where he was coming from till I started thinking back to when I first got mine and tried to drive it like a manual as much as I could...it never had stumbling issues...now it dies when I am in gear! But hey, I bet everyone is sick of hearing the fight for manuals, so I am jsut gunna wait till I have the income and do the twin-turbo, maunal GN I've always wanted to do

 

[UNGN]

There are a bunch of drawbacks to this swap if you sit down and think about it logically.

1.) The Power band on our motors suck. If you put a larger than stock turbo on it, it won't spool until 3K, but if the motor is stock it runs out of steam a 5K. Port the heads and you'll only get another 800 RPM out of it before you endanger the crank. It aint no Supra.

Go stage II and now you are talking.

2.) Our bottom ends are spindly axially and not up to the task of the force of a clutch that can clamp 600 lbft of torque. Again... Stage II.

3.) Street Transmission techonology sucks for turbo cars. I've broken 3 richmond 6 speeds in 4000 miles with my 2+2. I would have broken is 3 times in 400 miles with my TA49 turbo internally stock motor. If you buy a T56, good luck EVER using 6th. Lock up your TC manually and drive around at 1400-1500 rpm. See how much it sucks. The Turbo won't spool until about 140 mph in 6th and a low compression v6 is going to have a tough time pulling 60 mph in 6th with out bucking you out of the car.

4.) Clutchs smoke pretty easily when you have a Turbo that doesn't spool until 3000 RPM, but when it does, you go from 150 ftlbs to 600 ftlbs of torque.

If you want to have "fun" and hot air motor with a manual would be fun. Fun and fast are two different things, however. To go fast with a manual, you need to spend money. A LOT of Money. If you spend enough, you will have a fast and fun.

 

[BJM]

Despite what I said earlier, I think these are some good points.

There are a bunch of drawbacks to this swap if you sit down and think about it logically.

1.) The Power band on our motors suck. If you put a larger than stock turbo on it, it won't spool until 3K, but if the motor is stock it runs out of steam a 5K. Port the heads and you'll only get another 800 RPM out of it before you endanger the crank. It aint no Supra.

I would agree that the tight powerband if made even narrower would really limit things but the 1st 4 gears in the T56 are pretty close in ratio.

2.) Our bottom ends are spindly axially and not up to the task of the force of a clutch that can clamp 600 lbft of torque. Again... Stage II.

These engines do seem to kill thrust bearings pretty easily even with an auto.