PT70 or 45a

[Double-L]

1987 grand national
3.8
Champion aluminum heads
1.65 rockers
205/210 cam
Hemco plenum
Accufab 70mm throttle body
Front mount Intercooler
65lb high impedence injectors (edge products)64.5 @ 43.5psi-80% duty cycle
Walbro pump,hot wired
2004r
10" 3400 Art Car convertor,no lockup
3.42 gear
LT1 mass air meter with translator
4" cold air intake
T-70 turbo
TA performance headers
ATR 3" down pipe
Turbonetics delta gate mark II 6psi
Turbonetics boost controller

This car was used for draq racing for the most part, I want to drive the car some and drive it to the strip and back, Would it pay to put a more streetable 45a on, Have had some guys say would be a better thing to do, Will run Mickey Thomspon 275/60/15 drag radials, Will fry the tires with the PT70 at 15 ponds of boost if you want to so would it be worth it, Turn the boost down and run the 45a to save the engine longer and get more torque? Have Alky kit that is going on it to, A friend also said to come down on the gears to like a 3.90 with the tall tires?

 

[Epitome]

I would never change the gears....not ever, unless you were going to a significantly taller tire than 28".

 

[Kevin87TurboT]

Definitely leave the 3.42 gears alone. They are much more streetable than 3.90 gears and turbo engines thrive on load.

As far as the turbo is concerned. I'd prefer the 70. If you're concerned about the engine's longevity, you can keep the boost turned down until you need it. If it were me, I'd install the alky kit and crank up the boost

Good Luck,
Kevin

 

[aquickv6]

I assume the 70 is a P trim .63? Keep the 70, you can always turn down the boost.

 

[bison]

I would never change the gears....not ever, unless you were going to a significantly taller tire than 28".

What is your current mph and 60ft in the quarter? Agreed on the above post, unless you were going to 3.23's and 28 inch tires, especially with the non lock up converter. 3.90's would be a big mistake. Especially with the non locker. I think you would gain very little going to a 45. If you want more hp and a quicker spool go to a 4bolt exhaust and tangential housing with a ballbearing center section. A GTQ would add a lot of hp at high boost levels also.

 

[Double-L]

What is your current mph and 60ft in the quarter? Agreed on the above post, unless you were going to 3.23's and 28 inch tires, especially with the non lock up converter. 3.90's would be a big mistake. Especially with the non locker. I think you would gain very little going to a 45. If you want more hp and a quicker spool go to a 4bolt exhaust and tangential housing with a ballbearing center section. A GTQ would add a lot of hp at high boost levels also.

Well it has never been run with the 65 lb injectors, New boost controller, 4'' cold air, LT1 mass air meter with translator,70mm throttle body,

With the old parts, Bad boost controller, 3'' intake, Stock throttle body going bad, with 28 inch tires it run 1.53 60 ft and 119 mph in the 1/4 mile, That was full slicks,

 

[Louie L.]

A PTE 70 GTQ makes about 25-30 hp more than a regular T70 at around 24 PSI. But there is nothing wrong with the T70. If you have NOT maxed out the current turbo i would not change it. Streetability wise a T70 and a TE45a are very similar.

 

[Double-L]

A PTE 70 GTQ makes about 25-30 hp more than a regular T70 at around 24 PSI. But there is nothing wrong with the T70. If you have NOT maxed out the current turbo i would not change it. Streetability wise a T70 and a TE45a are very similar.

I run it at 14 lbs on the street and 18 to 20 on the strip with the 42.5 injectors, Boost controller wasn't working right, Even at 14 lbs with the 42's it pulled like crazy

 

[bison]

Well it has never been run with the 65 lb injectors, New boost controller, 4'' cold air, LT1 mass air meter with translator,70mm throttle body,

With the old parts, Bad boost controller, 3'' intake, Stock throttle body going bad, with 28 inch tires it run 1.53 60 ft and 119 mph in the 1/4 mile, That was full slicks,

You have at least another 10 mph in there with the T-70 if everything is dialed in. 12-15mph more with the GTQ. Should go 10.40 with what you have now.

 

[bison]

I run it at 14 lbs on the street and 18 to 20 on the strip with the 42.5 injectors, Boost controller wasn't working right, Even at 14 lbs with the 42's it pulled like crazy

Thats way below the hot spot for that turbo on a 231ci. You wont see big gains vs. a much smaller turbo like a TE61 at those boost levels. Put some injector in there and turn it up. Then comment to us on how it pulls :biggrin:

 

[Double-L]

Well we got it all together and the drag radials on it, Running it at 23 lbs of boost, Something isn't right, The guy working on it run a scan on it and says it is OK, No knock, Running racing fuel, I drove it and it pulled real good a few times, No as much as I would like and coming out of the hole at 5 lbs of boost, Wish I had a lot more there, The guy says I want to much, After a few hard runs, Not at the strip but a safe place it felt like it drooped to a V5 not miss but poped, Slowed down, Almost like floating a valve , Checked the tach and the guy said I was hitting the rev limiter, It was at 6,000?, Said he was going to put a better servo on the tranny, Can't get the shift point to stay at the right place, Over heated to so we put two fans on and still hot, He said he thought it was the under pulley so he put a stock pulley to turn everything faster, Said that could be a problem to battery getting low and causing problems?, Seems I have a lot of problems, Does this sound about right or should I look at something else, Going to try and get it to the strip Wednesday to see what it will do

 

[Double-L]

Well took it to the strip, Slower with new parts, The direct scan said everything was ok other than the tranny, Big jumps when it shifted, It run 1.80 60 ft. 12. flat at 120 mph, Real slow off the line, and I could only get 80 percent throttle opening, A guy said you wouldn't gain anymore with 100 percent, Most say drop the tranny and get it fixed and put a 45A or smaller turbo on, It pulled just as hard at the end of the 1/4 as it did at the 1/8, If we had another 1/4 to go I might have hit 200

 

[bison]

Well took it to the strip, Slower with new parts, The direct scan said everything was ok other than the tranny, Big jumps when it shifted, It run 1.80 60 ft. 12. flat at 120 mph, Real slow off the line, and I could only get 80 percent throttle opening, A guy said you wouldn't gain anymore with 100 percent, Most say drop the tranny and get it fixed and put a 45A or smaller turbo on, It pulled just as hard at the end of the 1/4 as it did at the 1/8, If we had another 1/4 to go I might have hit 200

What was your mph in the eighth? You will gain at 100%. Timing and fuel will change at 100 % throttle. You need to get that 60' down. What is your launch technique? What was your boost pressure on theses runs?

 

[Double-L]

What was your mph in the eighth? You will gain at 100%. Timing and fuel will change at 100 % throttle. You need to get that 60' down. What is your launch technique? What was your boost pressure on theses runs?

It was 98. something don't have my time slip close, I changed my launch for this run, No burn out, Bring it to about 5 lbs boost nail it, Did cut a .008 light, I could tell it had tranny problems, After I posted a guy unhooked the tranny cable and it had 100 % but wouldn't shift, Put cable back no full throttle

 

[bison]

After I posted a guy unhooked the tranny cable and it had 100 % but wouldn't shift, Put cable back no full throttle

That transmission needs to come out now for sure. You smoked the drum, band, directs, and probably the forward clutch pack if you drove without the TV cable hooked up. You need to leave with more boost than you are or your 60' will suck with that turbo.

 

[Louie L.]

It was 98. something don't have my time slip close, I changed my launch for this run, No burn out, Bring it to about 5 lbs boost nail it, Did cut a .008 light, I could tell it had tranny problems, After I posted a guy unhooked the tranny cable and it had 100 % but wouldn't shift, Put cable back no full throttle

Double L,
Please check with us before you let friends tell you mis information and pull things off the car.

This unhooking of the "trans cable" quite possibly runined the transmission if you ran it . Although it sounds like your trans needed a rebuild anyways due to the flare at the shifts, many techniques that would be applied to other cars dont work on TRs.

Its important that you get the trans fixed before throwing a turbo on it.

Also depending on what engine management is in the car having it read 100% WOT will have a great impact on all out performance. 120 MPH depending on boost is not too shabby.

Work on making the car right before any more track outings. If not you are just not going to be happy.

Just trying to help and save you some money..

 

[Double-L]

Double L,
Please check with us before you let friends tell you mis information and pull things off the car.

This unhooking of the "trans cable" quite possibly runined the transmission if you ran it . Although it sounds like your trans needed a rebuild anyways due to the flare at the shifts, many techniques that would be applied to other cars dont work on TRs.

Its important that you get the trans fixed before throwing a turbo on it.

Also depending on what engine management is in the car having it read 100% WOT will have a great impact on all out performance. 120 MPH depending on boost is not too shabby.

Work on making the car right before any more track outings. If not you are just not going to be happy.

Just trying to help and save you some money..

Oh no I didn't bring it up to boost with the cable unhooked, Didn't even get on it, Just poked alone with the laptop hooked to it, We wasn't even at the strip, Out in the country, When it took so long to shift to 2nd at a slow speed we pulled over and he hooked it back up, Stoped and got on it and taped it through 1,2,3, and that is where we seen the spikes after we got back to his shop, Not had the Buick back to the strip and it will stay home till we get the tranny rebuilt, I thank all the people that take the time to try and help

 

[bison]

At this point i would contact Chris at CK and get a billet forward drum AND dual feed the direct clutches. You will hit some great numbers when you get it dialed in with more boost and harder launch. Its possible your TV cable is worn out at the detent. I had one about 6 years ago that wouldnt hold in position unless i pulled it forward too much. Then it wouldnt allow WOT when pedaling from inside the car. You may want to try a new cable with your fresh transmission.

 

[Double-L]

Well thought I would put this here as it does have a lot to do with the car, Went to the Buick show and race at Indy to day, Had a great time, Drove my Grand National down, I know I still don't have the tranny fixed yet but it doesn't slip while it pulls and I took it easy, I had a small place on the back and one on the front so I took it to the pantless fixers, I pulled in and they didn't want to touch it at first, Said oh man never been painted and looks like it came off the show room floor, But they fixed it right up and the car does look brand new now, My wife rode in the back seat, Hard to beleive she has been the only person that has ever set in that seat that I know of, Great show, Had number 1 GNX and some hot race cars, Well I have been trying to think keep my 70 or go 45a well I talked to Cotton at the show and he put a BB 66 P trim on it while I waited, Man is that one nice turbo, I would have made a few runs if my tranny was fixed, It feels real strong

 

[Epitome]

I went 10.57@127mph with that 66 P-Trim ball bearing turbo at 25lbs of boost and 26 degrees of timing/3600lb car with me in it..off the foot brake....spools great, drove it in a rarely driven street car...you will love it with your combo... your heads are better, my cam was a hair bigger (no big deal). I had a 19930 3500 stall AC non Lock Converter. I think you made a good choice, wait until you rip it

You may want to start thinking about double pumpers, just to be safe.