yet another T56 question

[93formula]

im new to the board and new to the 3.8 buicks all together. i own a 93 lt1 powered formula. im looking inot dropping the lt1 for a turbo buick motor. my car is equipped with a t56 transmission, and after doing a search i see everyone recomending against it mostly due to the cost of installng it in a GN and it makes the car slower.

i dont fully understand how exactly it makes the car slower other then the ecm problems and spool. i will be going with a DFI setup for the ecm, so that takes care of that area now im too sure on spool and turbo lag and how exaclty thats related to the t56.

agian im new to the area of turbo buicks and thanks in advance for your advice.

 

[Taffy]

These engines do not rev very high. 5000 stock and they are done. If you used the 6 speed, you would be shifting before ya made any appreciable boost. Now with an auto, the turbo is loaded even during the shifts. Plus 15+ psig launches on the converter are nice (have not done one yet).
TO get the 6 speed to work better, you need to put it behind an engine that spins higher (6000+). ERIC.

 

[GNVAIR]

Same advice to you as everyone else. You obviously have the loot,so try it out and see how it works. Dont say we didnt warn ya

 

[Sleeper]

One of the ways it makes the car slower, is the time it takes you to shift. I don't care how fast your right arm is... you can't match the speed of the automatic. I used to run a Muncie rockcrusher with a vertigal gate shifter [pretty hard to miss a shift with that shifter ] and I thought I could bang the gears pretty good, but was no match for the automatic. And as Taffy said, you loose boost when you shift, even power shifting and the torque curve is very low RPM wise.
Another thing, it is really embarrasing when you miss a shift trying to show off (That comes from first hand experience running a T5)

Paul

 

[93formula]

hmmm, so in between shifts the turbo losses boost? i think im beginning to understand the concept here but if i were to equip it with a A4 then all would be fine? wht MHP do these cars run out of breath?

 

[93formula]

well here are my gear ratios out of my tranny

1 3.36
2 2.07
3 1.35
4 1.00
5 .80
6 .62


now at the drag strip ill get up to forth, now i understand the boost doesnt build tll about 2600 rpm, but wheres the peak boost made? and if i do shift at between 5-5300 rpm, i cant see dropping more then 2-300 rpms in between shifts, and lossing maybe what 3 psi of boost? and my rear gear ratio is 3.42 with that setup. would going to 4.10s help with the loss of boost due to low rpms?

 

[azgn]

60' times being the most important element, how do you propose building boost at the line in order to launch effectively? These motors don't make a lot of HP without boost......guess you could be like the manual Supras and make it up on the big end, but you are giving up the main advantage of these motors.....torque

if you want to go fast, use an automatic!

 

[93formula]

by using programming via DFI would i be able to work out the loss of boost at low rpm? also poeple are mostly against the manual swaps for 1/4 mile times, but how would this apply to street racing and highway racing? wouldnt manual be prefered? again im thankful for everyones input and i am leaning towards the auto but since having the t56 already there i would like ot retain it if possible. most of the racing that happens with me is from a roll any way and ill only make the strip perhaps six seven timess a yaer.

 

[Sleeper]

Do you know anything about programming a DFI setup? It is not a magic fix that will make boost quicker. I don't know why you think a stick would be better on the street or Hwy ??? These are torque monsters that pull like freight train at relatively low RPM, so you don't need to rev them up to make power.
You can not apply the same principals that you would use with a naturally aspirated motor to these motors. This is not a small block Chev. It is a computerized sequential fuel injected beast. The HP and torque curves are much lower in the RPM band. Unless you do some valvetrain modding you are out of steam at around 5000 rpm.
Boost does not build along with the RPM; it is dependent upon sensed load and other factors. Full boost can be produced at 2300 RPM or less, that is the beauty of these motors.
The engineers that designed this setup spent a lot of time figuring out what will work best combo wise.
Do a lot more tech research and reading on these motors so you will actually understand how they work. This is not just a weekend swap you are getting into.

Paul

 

[93formula]

i will be doing my own programming as i have a DFI setup on my lt1. i fully understand that these are different mtors that is why im still not comprehending the complete reason as to why i shouldnt stick with my t56. okay so this motor has a low torque curve, and builds full boost below 3000 rpm, why isnt this useable with a t56? due to strentgh? if the car runs out of steam at 5000rpm how does that affect the use of a auto vs a t56? i dont want stick just so i can rev the motor higher, if i have to shift at 5000 i will do so, and if i do run out of steam at 5000 then wouldnt having the extra gears be bennificial? isnt it the MAF that senses the load? im trying to figur out exaclty why i wouldnt want to keep the t56, from what i can tell its1: autos shift quicker 2: something bout spooling at the line. now why cant i spool with a t56????? i had a turbo laser for a while and i had no trouble building boost with that motor on a 5 speed. and thanks for all your imput im not trying to be a jerk here just trying to figur out the reasons why everyone says dont do it.

 

[93formula]

Originally posted by azgn
60' times being the most important element, how do you propose building boost at the line in order to launch effectively? These motors don't make a lot of HP without boost......guess you could be like the manual Supras and make it up on the big end, but you are giving up the main advantage of these motors.....torque

if you want to go fast, use an automatic!

how does the manual differ from the auto in the area of creating boost? this is where i get lost i thought the engine senses load at the maf not the torque converter.

 

[FJM568]

The MAF only tells the motor how much air in going in it...The ecm calculates load based on throttle position, MAF, speed, rpms, and probably some other stuff that escapes me right now...The computer DOES NOT sense boost though...

You can rev the motor all day in park or neutral and your boost guage will show 0 boost all the time...Other than that, I really can't tell you much more about how it builds boost...

I do know that people have tried to put manuals behind these turbo Buick motors and they went slower, every time compared to automatics...People have tried just about every combination with these motors over the last 15 yrs., so there is a lot of knowledge here and on www.gnttype.org You'll just have to take people's word for it, they've BTDT...They're trying to save you time, money and a lot of frustration...

 

[93formula]

okay so would you guys have any idea how much slower? im not trying to build a 10 second car here, just somehting that will run in the low 12s to high 11s. ive currently have a nitrous setup on the car that i could use to launch out of the hole with would the car pick up boost after the launch and carry me through? again idlike to thank everyone for there patience and understanding m ignorance.

 

[GNVAIR]

The perfect example was GM when developing the Turbo Trans Am in 1989. There were several prototypes equipt with manual transmissions. GM scrapped both of them as they were substantially slower than their automatic equipt counterparts.
When I say substantially, I mean by over a full second in the quarter. I dont care how good you are with DFI, you WILL not get it to go faster with the stick. DO an archives search on this subject, you will see that I and several others have done this before. You will be very sad and will waste a lot of time and money. If you have DFI already, then why not just buy a twin turbo kit for you LT1??

 

[KendallF]

The turbo needs exhaust flow (and a lot of it) to build boost. Without a load on the motor, it can't get the flow it needs to build boost. Automatics can load the motor against the converter, build boost, and launch with the turbo already spooled.

With a manual, your options are to leave w/zero boost, or use some sort of a rev limiter/timing retard arrangement so you can WOT the car and spool it. The rev limiters work (witness the Lenco'd turbo cars like Rieger, Moran, some of the import guys) but can be hard on the motor. They're really not an option to use at every stoplight.

If you're not building primarily a track car, it would probably be fun with a manual..there are several points to consider that haven't been touched on yet, however. Even a mildly modified 3.8 turbo motor is a torque monster, compared to the LT1. You will have a hard time finding a durable clutch. That leads to point #2...the BOP bolt pattern and finding a flywheel for your swap. You can use an adapter on the bellhousing, but you'll need a custom flywheel, probably linkage work, etc. etc.

In terms of "swap hassle", keeping the T56 will be MUCH more of a PITA than just swapping a 200-4R in there and changing the crossmember and torque arm mount.

 

[monte_383]

I'm gonna put my foot in my mouth and throw out the idea anyway. Not that I'm reccomending it or anything, but how 'bout an anti-lag system like they use on rally cars. I ain't 100% certain of their inner workings or how long your turbo will last, but you might be able to gain a little boost back (or not lose as much) during shifts with something like this. And I do agree the only tranny to have behind a turbo engine for drag racing is an auto. Leaving the line w/o boost in a stick car is just not the same. I've driven both, no matter how I feather the clutch on the WRX, I can't get much boost on launch. -Chuck

 

[Sleeper]

It is really hard to explain the difference, unless you actually feel it. You live in Vancouver, there are a bunch of guys that have TR's out there. Do a search of B.C./Vancouver TR clubs etc.
This may help you find a link to the club
http://www.turbobuicks.com/ubb/Forum31/HTML/000167.htm
They have a Buick day down at Mission Raceway a few times a year

My advice is try to get a ride in one of their cars, something that is done up a bit, and you will see and feel why using a stick will suck.
As I have tried to explain to you before, from first hand knowledge... The automatic is quicker and a much better setup, but you seem intent on using the T56... so try it, and let us know how it works out . Good luck

Paul

 

[93formula]

thanks guys for all your input.

here is what a member responded to one of my other threads:


I'll try and explain this the best I can............

The torque converter slips against the motor causing a load. When you are driving up a steep hill it takes more effort for the motor to maintain your current speed right? Thats because the hill is putting a load on the motor kind of like the converter does. The motor is forced to work harder thus producing more exhaust gasses that the turbo runs off of and it does so at a much lower rpm than you possibly could with a manual tranny. I know all about two step rev limiters that some manual turbo cars use but that is only applicable on launch and even then its not as effective as an auto because the boost falls back to zero when you shift. With an automatic, the converter is always slipping somewhat which maintains the load and gives you constant boost until you let off the gas. These motors do not rev high at all. If you hook up a manual tranny to one of these motors it wont even build any boost until you are damn close to redline and at that point you will have to shift and the boost will drop all the way back to zero. You will only be in boost for a split second until you are forced to shift and until then you have a car with a good bit less horsepower than a Honda Civic that weighs 3600 lbs. If you are dead set on a manual tranny then you should stick with the LT1 or get a Supra or RX7 with a manual. Turbobuicks are not in the same boat as these other cars because they make their power significantly lower in the rpm band. Thats why turbobuicks are referred to by many as one of the best quarter mile vehicles to ever come out of Detroit. Torque rules the dragstrip and thats one reason why turbobuicks are great dragracers, because they produce ungodly amounts of torque.

To sum it up:

Auto trannies use load to make the engine produce boost lower in the rpm band in which it was DESIGNED for whereas manuals rely on engine rpm to build boost and RPM's is not what these motors were DESIGNED for. The turbo wastegate dictates whether your exhaust gasses will be used to create boost or just routed out your exhaust through the downpipe, but that is a whole other explanation.



okay so i realize that the auto is gonna be waaay faster. i can always leave off the line with the current nitrous set up i have in my car. now if the wastgate dictates weather the gasses are routed to the turbo or not, isnt there a way to dictate the wastegate to dump the exhaust into the turbo earlier?

how long does it take to build the boost? the only turbo experience i have is with my chrysler laser i owned which was a 5 speed. the turbo spooled damn fast in that car and when i did shift gears the boost did drop to zero but the instant i steped on the gas and was in gear the boost was back at the peak, i didnt have to build it back up again. maybe thats why im cunfused here as to why i shouldnt use manual.

 

[GNVAIR]

Why do you have to be so stubborn? You have had some of the most knowledgeable turbo Buick guys respond to your questions and they all responded as honestly as possible. They wont kid you. If you want to keep your 6 speed, then you should honestly be thinking about something else like turbocharging your LT1 or installing some sort of stroker motor. Turbo Buick V6's dont like sticks. If you think you know more than everyone else, then do like some of us said and try it and see how it is; but dont say we didnt warn ya.

 

[93formula]

im sorry if i seem so stuborn, the reality is im new to this set up and am really curious as to why exaclty the motor wont make boost till it hits high rpm, and how come there isnt a way around it. i understand that i wont leave the line with max boost, thats not my concern, my concern is HOW MUCh SLOWER is it gonna be, a full second? again im not trying to find an excuse to say the manual is gonna be just as fast. im just trying to find out how much of a difference its gonna be and if im willing to live with that difference. as you see in my posts i have many questions. how long does it take to spool the turbo from a dead stop? like if i had an auto and it ran say 11s,would a manual equiped one run 12s? thanks everyone for bearing with me.