Grand National Thought

[someguy2112]

I was thinking would it and is it at all possible to swap out the Automatic Trans for maybe a four or five speed manual Trans, and how much would there needed to be involved? I always have pondered this question but has anyone ever attempted it? Just a thought. i'd like to by a Grand National and slap a four or five speed on it and just bang them gears how sweet would that be!

Thanks,

Leo

[mygs462]

The problem with a manual transmission in a Turbo car is between gears while shifting you would lose the boost that was built up, so the turbo would have to spool up all over again, not as much as from a dead stop but I think you get the idea.

[Floydsbuick]

So how do stick shift turbo cars like WRXs and Lancers do it?

[MPRY1]

I was thinking the same thing.

My WRX that I had (before the ex got it in the divorce):( was a 5 speed that had a computer controlled waist gate that limited boost in the 1st 2 gears and it still got up and boogied even with the lower boost in 1st and 2nd. I don't see why an engine with 2 more cylinders and a much bigger turbo wouldn't do OK with a nice 5 or 6 speed manual.

[mygs462]

They do it with MUCH smaller turbos that spool up much quicker, and to relatively LOw boost compared to the 20+ #s we'd run in a TR, so the Loss is much more minimal.

[72staged]

If you've driven a GN you will know that if hit the throttle and so much as even back off a slight amount, you will lose all of your boost. And you will not get it back in an instant. In my opinion,the forced air system on a stock GN will not work well with a manual transmission. Maybe a smaller set of twin turbos and a wastegate management system as mentioned above may work. Maybe do some homework on the Evos, Porsche, and some other good performers with manual transmissions. You may be able to make something really fun with the GN.
I always did like the 1-2 shift at full boost on my GN. Felt like I was going to fly.

[87GN_70GS]

When the throttle closes shut on a shift, there will be lots of pressure in the intake since the turbo is still going. A blowoff valve will help relieve the pressure. A BV that is exhausted back into the intake tract (instead of to atmosphere) might help with boost decay since the built-up boost will be recirculated instead of vented. Dunno how much this will help tho.

[Electrajim]

It's been tried and tested before. Results were slower ET.

Stick with the TH200 for street strip duty.
If you are going to race only, get a TH400.

ElectraJim
86 GN
77 Electra 225, 455

[Floydsbuick]

What about a good ole powershift? :3gears:

[Eric Schmelzer]

What about a good ole powershift? :3gears:My theory is that under full boost it would end in broken parts.

[MPRY1]

When the throttle closes shut on a shift.....

Well, there's your problem, if your shifting a manual trans "properly" the gas pedal should be firmly planted on the floor.:Brow: :3gears: :laugh:

[sailbrd]

Well, there's your problem, if your shifting a manual trans "properly" the gas pedal should be firmly planted on the floor.:Brow: :3gears: :laugh:

"gotta be good now powershift her she comes"
The Beach Boys :TU:

I think it would be a good project with the new transmissions and ball bearing turbos. Would have to be tuned a little different. Would not have to worry about how much boost the brakes could hold.

Don't cut up a GN! Lots of TR's to mess with. On second thought go ahead and cut one up.... makes mine more valuable. :Smarty:

[MPRY1]

I agree with you. I still feel there is no reason why a GN with a 5 or 6 speed can't run as good or better then an automatic car. There are TONS of European and Japanese imports running very strong with manual trans, small displacement engines and turbos. Weight on most of these cars are pretty close to a GN as well. If you just stick a manual trans behind a stock GN engine yea it would probably not perform well, but if somebody actually sets the car up properly it should rip!!:3gears:

[greg davis]

Even if it wasnt quicker it would be 10 billion times more cool :cool:

[austingta]

Even if it wasnt quicker it would be 10 billion times more cool :cool:

But that doesn't matter to GN guys-- the plainer the better. All my GN friends care about is that ET slip...

[Floydsbuick]

I gotta say, jamming gears in my Regal was very cool. Every once in awhile a real gear jammer would pick up on the fact that it was a stickshift car without looking. Very Cool!:3gears:

[MPRY1]

Even if it wasnt quicker it would be 10 billion times more cool :cool:

Amen to that brother Davis!! :laugh:

[someguy2112]

I think it would work because turbo technology has gone a long way and there is very little lag. even if i did put a conventional turbo that takes forever to spool up there are alot of great systems out there that would completely control exaust upon each shift. And besides it woulld be awesome to bang gears in a Regal! just wanna need to find a regal first.. doesnt matter what year either I love these Projects!

[Floydsbuick]

*sigh* http://i156.photobucket.com/albums/t24/floydsbuick/100_2148.jpg http://i156.photobucket.com/albums/t24/floydsbuick/100_2151.jpg

[MPRY1]

Dan,

I was impressed when I first saw that car at the BPG Nats. I thought it was bad ass. You REALLY need to get it running again!!!:3gears:

[Floydsbuick]

Yeah...it was fun. Although I never could get out of the 14s.

I do miss shifting really bad:3gears:

[AbeWhat]

It was done by a car mag back in the day, made the TR a second slower in the quarter I think. Definitely was slower, with a good driver and all.

[MPRY1]

So I guess if it's been tried once 20 years ago no one should ever try it again? :puzzled:

Back in the day they did not have whats available now computer wise for tuning, roller bearing turbos that spool up faster, etc.. Technology marches forward.

I still think if a 3300 pound Subaru WRX STi (yea they are that heavy) can go incredibly fast with a six speed manual, a smaller engine and a smaller turbo, there is no reason why a Turbo Regal can't do the same if not better. It's not like Buicks are on some other plain of physics. :laugh:

[AbeWhat]

i dont think they exist on another plane of physics, no. hmm. But there is a good case for using a big turbo/big converter setup that is very popular for drag racing setups. 1. Building boost at the line 2. keeping it floored through gears... Not saying a manual is impossible at all, just going fast in a straight line in a turbo regal is easier/cheaper with an auto. Go to gnttype.org and search their forums, there are many posts proposing this idea, and a good amount of discussion. Some research on the TR's, not WRX's, will turn up a lot of info.

[Electrajim]

More 5 speed info here.
http://www.gnttype.org/forums/showthread.php?t=7879

ElectraJim

[CTX-SLPR]

The way a manual is spooled on the line is to retard the timing so far that it burns in the headers creating the load you need for the turbo to spool. This does all sorts of weird things for the metalurgy of the headers and for the EGT's. The bigger problem with a stick is the instant a brutal torque. Not saying you couldn't build a tranny to handle it but in testing on the '89 Turbo Trans Am they tested it with the T5 and no only was it atleast 1s slower it also shredded the trans in only a few hours of testing. Granted a T5 is junk to holding that kind of power but still its a lesson not to be ignored. The import motors don't torque as hard as the Turbo6 since they are sometimes less than half the size. Smaller motors mean smaller turbos which have less systematic losses due to bearings, wheel interia, and tubing lengths. This also has the side effect of requiring a blowoff or bypass valve to keep the turbo from not only spooling down but reversing direction and trying to pressurize the exhauste due to the pressure going backwards across the compressor.

Sorry but the cool factor on this is so outclassed by the practical issues that I personally don't think its a good idea for anything but a LSR car. A good shifter on a properly prepared and cooled TH200-4R will be all that even a AutoX car really could use without having a ON/OFF clutch and unubtainium internals on the trans.

[BadBrad]

Turbos are well matched to automatic transmissions because they are both non-linear energy transfering devices. The turbo provides almost no power until it reaches a certain rpm - then power climbs rapidly. Essentially, the same thing happens in the torque converter - at a certain rpm the power transfer climbs rapidly. I read a description of torque converter operation once that indicated some crazy immense momentary multiplication on the order of 25 to one. Tune the turbo to approach peak somewhere around the converter stall speed and look out.

[sporty-to-GN]

There's a thread re. manual conversions at turbobuick aswell. And it argued the same as it has here...until...some one mentioned the Buick V-6 lacks the thrust bearing/webbing strength to hold up as well as it would with an automatic.
The cruising coolness factor would be there.
In addition to the block, I don't think the body/frame would hold up very well to the torque shock of a manual trans for long. Although they weigh about the same a 68-72 GS, the sheet metal and frames are not as durable. The frame and 1/4 panel on my relatively stock GN have the cracks to prove it.
With mileage these cars tend to become rattle traps. I can here it now, like a sledge hammer to the dash with every WOT dump shift!

Do what you will and make it your own. Personally, if I had the inclination, I would go with a hyraulic pedal set up. Why use an antique pedal linkage design on ECM muscle?

[bob k. mando]

The problem with a manual transmission in a Turbo car is between gears while shifting you would lose the boost that was built up, so the turbo would have to spool up all over again


stick shift turbo's aren't very good unless you're driving them hard. if you scream the engine out to ~6,500rpm and then drop down to 4,000rpm for the next higher gear you'll still have the turbo 'on boost'.

do you intend to drive that way on the street?

the specifics will vary depending on how the turbo system was designed and set up but you shouldn't do this without researching very carefully where your expected shift points and minimum engine rpm for turbo boost are going to be.

most of the modern cars get around this by using extensive computer controls and variable vane/inlet turbo systems.

[rdj59]

When i turboed my b2200 with a 5 speed i didn't really have a problem with boost lag between gears. As long as you use a blow off valve to relive the intake pressure it should stay spooled. When you shift the turbo is still spinning very fast and takes a split second to shift and your back on the gas again enjoying the boost. It worked just fine for me. Sure an auto is ideal but what do you want, something you would enjoy driving everyday or something you only enjoy one day a week?

Jeramie