Converter lock up question...

[Scott89TTA]

I know my setup isn't optimal but the plan is to deal with it until I could afford to do the heads and cam. I have only run the car a few times with my current mods (see sig, not listed 100# springs installed) and so far have not yet locked the converter. A lot of people keep asking me if I have locked the converter yet...telling me I will improve my et a little pick up a some more mph ? When and how should I lock the converter? Also would my current setup benefit from raising my boost from 24 to 25 or 26 ? I'm guessing the stock heads and cam aren't going to do much more...the heads do have come very light porting (more gasket matching then anything) that I did while they were off replacing the head gaskets, also cleaned up the exhaust side and header welds as well.

Using the trans brake the converter spools the GT6776e pretty good but just driving around on the street it isn't bad but is a little sluggish until I get it spooled up...I figure heads and a nice roller cam will cure that when I am ready. I am using tractor fluid as recommended do to the StageRite trans brake.

here is a thread on my best runs to date http://www.turbobuick.com/forums/tu...est-tune-mason-dixon-dragway.html#post2341673


Thanks

 

[JP112_89]

...

I lock the converter at 75-76mph. Worked best for me according to the L cheapo g-tech.

Ond wire from a ground point to your switch. From the other side of the switch to pin F of the ALDL connector.

Thereby closing the switch applies ground to pin F and on to the lockup solenoid, locking the converter.

 

[Scott89TTA]

I lock the converter at 75-76mph. Worked best for me according to the L cheapo g-tech.

Ond wire from a ground point to your switch. From the other side of the switch to pin F of the ALDL connector.

Thereby closing the switch applies ground to pin F and on to the lockup solenoid, locking the converter.

Thanks...so you need to flip the switch during a pass ? Would be nice to flip the switch on after your burnout and then have this automated through the chip at a pre-selected mph...

Bison and or Dusty could you comment on my current setup and should I be able to get more out of it at the track or am I maxed out until I do heads and cam?

Thanks,
Scott

 

[bison]

You dont need to use a switch to lock the converter. You can have it burned into the chip at any mph you want 2nd through 4th at WOT. As far as the combo goes you need to run the 6776 a lot harder to get the mph up. Your still kind of limited if you have a stock intercooler even with heads and cam since the pressure drop across the intercooler at high rpm will be drastic once the engine is able to breath. Id keep the 9x11 and crank the boost up as high as possible. Try to keep the engine between 4500 and 5100 as much as possible with as high a boost you can stand locking the converter. Heads cam and intercooler would be worth 175-200hp on a good tune at 27-30 psi boost over what you have now. Car would trap 135mph if you have enough pump. Just keep increasing the boost and throwing more alky at it but stay under 5100 your mph will climb up quick.

 

[Dusty Bradford]

Thanks...so you need to flip the switch during a pass ? Would be nice to flip the switch on after your burnout and then have this automated through the chip at a pre-selected mph...

Bison and or Dusty could you comment on my current setup and should I be able to get more out of it at the track or am I maxed out until I do heads and cam?

Thanks,
Scott

I agree with everything Bison stated. The other very important part is your valvesprings. As you crank the boost up you will reach a point where the car doesn't respond to more boost and that is a sure sign of lack of spring pressure.

 

[TurboDave]

Thanks...so you need to flip the switch during a pass ? Would be nice to flip the switch on after your burnout and then have this automated through the chip at a pre-selected mph...

Bison and or Dusty could you comment on my current setup and should I be able to get more out of it at the track or am I maxed out until I do heads and cam?

Thanks,
Scott

If you were running an extender chip (a perfect match to your translator), you'd already have a programable WOT lockup speed in the chip, and also a programable cruise lockup. No switches needed.

 

[Scott89TTA]

You dont need to use a switch to lock the converter. You can have it burned into the chip at any mph you want 2nd through 4th at WOT. As far as the combo goes you need to run the 6776 a lot harder to get the mph up. Your still kind of limited if you have a stock intercooler even with heads and cam since the pressure drop across the intercooler at high rpm will be drastic once the engine is able to breath. Id keep the 9x11 and crank the boost up as high as possible. Try to keep the engine between 4500 and 5100 as much as possible with as high a boost you can stand locking the converter. Heads cam and intercooler would be worth 175-200hp on a good tune at 27-30 psi boost over what you have now. Car would trap 135mph if you have enough pump. Just keep increasing the boost and throwing more alky at it but stay under 5100 your mph will climb up quick.

So at what point would you lock the converter ? Not sure if my Turbo Tweak chip has that option...if not I'll check with Eric. According to my PowerLogger files when using the Stagerite brake it is shifting from 1-2 at 5200 as long as it is hooking and then I shifted 2-3 at ~5000. On my best pass to date I shifted past D to OD (not on purpose) it shifted to OD ~5100 and then trapped around 4700 @ 116.22 mph. On my next best pass I got loose out of the hole still getting a 1.57 60ft and it shifted 1-2 at 4890 and then I shifted 2-3 (no OD) at 4964 and then trapped 5370 @ 113.78 mph. Will locking the converter pull the RPM down or should I look at maybe a little taller tire or use overdrive ?

I agree with everything Bison stated. The other very important part is your valvesprings. As you crank the boost up you will reach a point where the car doesn't respond to more boost and that is a sure sign of lack of spring pressure.

I am currently running upgraded 100# springs...one of the 1st things I did when we discovered the stock springs appeared to be floating the valves at about 3200-3500 on some dyno pulls.

If you were running an extender chip (a perfect match to your translator), you'd already have a programable WOT lockup speed in the chip, and also a programable cruise lockup. No switches needed.

I may have to look into that...


Thanks,
Scott

 

[Scott89TTA]

You dont need to use a switch to lock the converter. You can have it burned into the chip at any mph you want 2nd through 4th at WOT. As far as the combo goes you need to run the 6776 a lot harder to get the mph up. Your still kind of limited if you have a stock intercooler even with heads and cam since the pressure drop across the intercooler at high rpm will be drastic once the engine is able to breath. Id keep the 9x11 and crank the boost up as high as possible. Try to keep the engine between 4500 and 5100 as much as possible with as high a boost you can stand locking the converter. Heads cam and intercooler would be worth 175-200hp on a good tune at 27-30 psi boost over what you have now. Car would trap 135mph if you have enough pump. Just keep increasing the boost and throwing more alky at it but stay under 5100 your mph will climb up quick.

Wow...I like the idea of 175-200 more HP over what I currently have I think I will need some bottom end work for 27-30 psi though. How much boost can I run on a stock bottom end and pistons ? The car has just under 50k miles, 100# valve springs, new head gaskets, and ARP Pro Series head bolts.

So at what point would you lock the converter ? Not sure if my Turbo Tweak chip has that option...if not I'll check with Eric. According to my PowerLogger files when using the Stagerite brake it is shifting from 1-2 at 5200 as long as it is hooking and then I shifted 2-3 at ~5000. On my best pass to date I shifted past D to OD (not on purpose) it shifted to OD ~5100 and then trapped around 4700 @ 116.22 mph. On my next best pass I got loose out of the hole still getting a 1.57 60ft and it shifted 1-2 at 4890 and then I shifted 2-3 (no OD) at 4964 and then trapped 5370 @ 113.78 mph. Will locking the converter pull the RPM down or should I look at maybe a little taller tire (current tire is 26") or use overdrive which I thought was not a good for the trans ?

here are the Powerelogger files from the two mentioned passes. note: I have an issue with boost logging and also MPH scaling that is being looked into. MPH maxes out at 110 on my 116 mph pass and boost scaling is off on the bottom side 3 bar setting reads high (up in the 30's) but when switched to 2 bar full boost is correct...TTA w/3 bar MAP

Thanks,
Scott

 

[bison]

Wow...I like the idea of 175-200 more HP over what I currently have I think I will need some bottom end work for 27-30 psi though. How much boost can I run on a stock bottom end and pistons ? The car has just under 50k miles, 100# valve springs, new head gaskets, and ARP Pro Series head bolts.

So at what point would you lock the converter ? Not sure if my Turbo Tweak chip has that option...if not I'll check with Eric. According to my PowerLogger files when using the Stagerite brake it is shifting from 1-2 at 5200 as long as it is hooking and then I shifted 2-3 at ~5000. On my best pass to date I shifted past D to OD (not on purpose) it shifted to OD ~5100 and then trapped around 4700 @ 116.22 mph. On my next best pass I got loose out of the hole still getting a 1.57 60ft and it shifted 1-2 at 4890 and then I shifted 2-3 (no OD) at 4964 and then trapped 5370 @ 113.78 mph. Will locking the converter pull the RPM down or should I look at maybe a little taller tire (current tire is 26") or use overdrive which I thought was not a good for the trans ?

here are the Powerelogger files from the two mentioned passes. note: I have an issue with boost logging and also MPH scaling that is being looked into. MPH maxes out at 110 on my 116 mph pass and boost scaling is off on the bottom side 3 bar setting reads high (up in the 30's) but when switched to 2 bar full boost is correct...TTA w/3 bar MAP

Thanks,
Scott

Id go with taller tire and lock at the appropriate mph to keep the rpm int he target range. You can figure out the zero slip(locked) mph with the online calculators for various tire heights. Id ignore the power logger mph since it wont be as accurate as going by the measured diameter of the tire and backward through the gearing to get the actual numbers. If you figure out tire revs per mile you can figure out any of the zero slip mph info you need. Your not even close to the optimal area for the 6776 on your application. it will take 30+psi to be there. Ive ran over 700hp on the stock bottom end for a few months before it cracked the #1 piston. There is a thread about it in the engine section. You are about 250hp away from having to worry about the bottom end if you have zero detonation. If your trapping higher in 4th with the converter locked then you probably need some better springs

 

[bison]

Put in a manual lock up switch and id bet you gain at least 3mph on your current tune. Lock in 3rd at around 105mph. It should drop to about 4500. I just did the calc and you can go 121mph with 26" tires, 3.27 gears, and converter locked in 3rd at 5100 rpm. You need to throw more boost at it. Your converter slip on the 113.78 pass was about 11.7%. Not too good unlocked. It will get worse as you crank it up. It will need to be locked to get the mph

 

[Scott89TTA]

Thanks for the info Bison...found the calulators on the TCI website http://www.tciauto.com/Products/TechInfo/Calculators.asp and got the same results as you did. I'm hoping to try it out this weekend at Cecil for some test & tune

-Scott

 

[Scott89TTA]

Put in a manual lock up switch and id bet you gain at least 3mph on your current tune. Lock in 3rd at around 105mph. It should drop to about 4500. I just did the calc and you can go 121mph with 26" tires, 3.27 gears, and converter locked in 3rd at 5100 rpm. You need to throw more boost at it. Your converter slip on the 113.78 pass was about 11.7%. Not too good unlocked. It will get worse as you crank it up. It will need to be locked to get the mph

Hey Bison...

check out this thread http://www.turbobuick.com/forums/turbo-trans-am-tech/304543-new-best-cecil-past-weekend.html

Thanks Bro

Scott

 

[Scott89TTA]

Ok...back almost a year on this subject. Last year Bison's advice payed off and I had my best runs to date. Now here I am with a somewhat new combo and have some questions. I have changed wheels and tires...now running skinnies up front 26" x 6" on 4" rims and 295/55-R15 (28") MT DR's on 9" rims out back. Previous was stock 245/50-R16 on 8" up front the and 255/50-R16 (26") MT DR's on 8" out back. My best locking the converter at 95-105 on the old combo in sig...ran the car this past Saturday with new combo. Best pass was 11.44 @ 108 1.54 60ft...earlier in the day I did 11.6 @ 115 1.57 60ft. With the taller 28" tire RPM is definitely down from the 26's but I thought my MPH would have gone up? My main problem of the day was the stock shifter...I was all over the place after releasing the Stageright trans brake. I know on my last pass I went from 1st straight to drive and then shifted into OD and either forgot to lock the converter or waited too long...RPM was around 4600 going through the traps...mph 108. I was running 26psi all day with no knock but was a little fat on the O2's at 810. Also launching the car at 10-12psi off the T-brake...car hooked nicely with no tire spin whatsoever.

What do I need to do to get back to where I left off last Fall 11.17 @ 119.7 1.53 60ft and improve ? Where should I lock the converter now with the taller tires ?

Thanks,
Scott

 

[turbows6]

I don't think your car likes the tire height. Your TTA has 3.27 gears, so with a 28 inch tire it's probably more like running a 29.5" on a stock geared GN/T-type. You are just pushing more wheel weight and taller effective gearing and making your car more prone to knock because both of those put more load on the engine. TTA's like 26-27" tall tires when running stock gears, and it sounds like you were hooking just fine with the 255/60's.

You need to ditch the stock intercooler too with that turbo. Yes, there are people that have gone fast on stock IC's, but they would have gone faster, or more reliably without it. My TTA picked up bout 5 pounds when I swapped in a modified 23 row SLIC from a Duttweiler neck stocker.

You would also have a lot more steam up top with a roller camshaft. Up at 5200+ you can tell power will start falling off with a flat tappet (mine did even with a 212/212 cam and a 23 row intercooler) and I think it has a lot to do with the springs that you can get by with. The problem with a crappy intercooler is that it really just makes you need way more pressure in the exhaust to make boost. Think of it this way,if you have 40% more pressure on the exhaust side than on the intake and you're running 25 pounds of boost that means you have 35 psi in the exhaust. With a stock 1.5 exhaust valve you'd have 62 pounds of pressure on the back of the valve, so you're 100# spring is acting like a 38 pound spring on the seat... then you don't have any top end power.

When I swapped to a 210/215 roller from a 212/212 flat tappet the car went from falling off at ~5200 to ripping quickly to 5500 before it shifts. That's where it now shifts 2-3 with a factory TTA valve-body. I have no doubts that the engine would pull pretty strong to 6000, but I have not and will not try that stunt on the street.

 

[Scott89TTA]

I have a lot of that in the works...Currently have a set of Champion ported irons with Harland Sharp rollers sitting and waiting for a nice roller cam. Also have a Dut neck TTA IC going in...my goal is low 10's. I don't think that will be a problem with the Dut neck TTA IC and Alky as many have been there on the same combo.

I'm quite sure my car would have gone 11.0 or maybe even 10.99 last Fall with a little harder launch and another pound of boost. When I went with new wheels and tires not one single person said to stay with the 26" tire...everyone said to go with 28" tires...the 295/55-15's are actually 27.8" I believe. Everyone said I should pick up another couple mph as well. I do believe my slower times & mph were more driver error thaen lack of power and a result of: missed shifts, not locking the converter at the right time or not at all and also running a little fat as my O's were 810 all day...on my previous best they were around 760-780. I installed a B&M OEM shifter detent plate that will now prevent my miss shifts...and allow me to go from the trans brake to either 2nd or drive depending on how I want to do it without going all the way to OD or even neutral.

Going to Cecil this weekend so we will see...just wondering where I should lock the converter now...2nd or 3rd and at what MPH ?

Thanks,
Scott