Does anyone have an idea which is a better way to set the Allison when making a 1/4 mile pass? Is it better to use tow/haul and lock the converter earlier, or not? Is their less or more stress by using tow/haul?


The truck felt faster in the non tow/haul mode, but I have no numbers supporting either way.

Tow/Haul would be better. Without the converter locked, you will generate tremendous heat. With T/H the converter is locked in 2,3,4 and 5 gears. In normal mode it only locks in 5th gear. It would be better to run in T/H, especially if you have a box. I also think you would run slightly better ET's in T/H mode.

according to the G-tec my 03 makes more power and is faster with the tranny in reg mode. also watching the attitude the tcc locks from 2nd on up when you romp on it. but i don't know if the tranny has more holding power through higher line pressures when in T/H mode.

Rocksam, that's exactly what I felt, that it was pulling much harder with the converter slipping somewhat. My concern is if the single disc torque converter is a weak point, locking up in 2, 3 and 4 early on is more abusive than letting it slip.





anyone have experience in pulling the trans on a 4x4? I have a hoist so clearance is not a problem, just wondering how much of a pita it is with the transfer case.

anyone have experience in pulling the trans on a 4x4? I have a hoist so clearance is not a problem, just wondering how much of a pita it is with the transfer case.





I've done it twice now, and probably soon to be a third time (helping someone else). The TCase is very light, and nothing to worry about. The Allison on the other hand is very heavy and requires two strong guys if your doing it on your back. Not a fun job by any stretch of the imagination, but very worth while.

If you pull the TCase, have an new gasket ready. The dealer has them for just a few dollars.

Rocksam, that's exactly what I felt, that it was pulling much harder with the converter slipping somewhat. My concern is if the single disc torque converter is a weak point, locking up in 2, 3 and 4 early on is more abusive than letting it slip.





anyone have experience in pulling the trans on a 4x4? I have a hoist so clearance is not a problem, just wondering how much of a pita it is with the transfer case.





I've done it once before.


I live in Saugus, lets get together and pull it!


We should have a tranny jack ready though.Edited by: Trippin

You will run faster in T/H, usually 2 to 5 tenths faster. I have tons of tracktime and slips to show it. Locked is always better than fluid transfer.

a stock converter with enough power might be faster in reg mode than T/H if the converter is slipping when locked up

If your converter isn't slipping or if it's been upgraded T/H mode with the converter locked will always be faster in the 1/4 mile.

"Lock It & Rocket"
http://www.dieselplace.com/forum/uploads/7E7_93C_peelout1.gif

Edited by: mtomac

I have raced alot and compared the the two modes. Non-T/H is up to a tenth faster. This was with a 90hp box only. The trans just takes two long to shift in T/H mode. Besides that you are loosing your torque multiplication running with the TC locked. (Not like we need more torque, but more is always better right??http://www.dieselplace.com/forum/smileys/Ermm.gif)


As far as heat, I made 8 consecutive passes in about an hours time and the trans never went above 150 deg on 70 deg ambient temp.


With a modded trans or a higher HP truck, T/H mode might be better, but if your trans is stock, you might as well be rowing a six speed with the amount of time it takes to shift.http://www.dieselplace.com/forum/smileys/Approve.gif And this is with alot of trans training prior to and during racing. Ultimately, you will have to decide which mode to race in.

I tend to disagree with 'locked is always better'


If the converter is making more torque (rather than just shearing fluid), and it keeps the power band of the engine in the torque peak longer, you will accelerate faster compared to locking up each shift and bouncing around the power band. I did a lot of testing for A-1 automatics in the 90's with several race cars and their converters, and we found as long at the converter had an efficient stator design, and we didn't cavitate the unit, we always went faster than if we used a locking set up (700r4 transmissions). When the locking converter would engage, it pulled the engine too low and we lost significant torque multiplication.


We even tried working on a 1-speed transmission set up, but had a hard time keeping the temps down to a reasonable level (sometimes they would exceed 350 degrees, but the car pulled extremely hard since the rpm was right in the middle of the torque peak always). The 2-speed powerglide would always be worth 1 to 2 tenths over a 3 speed turbo or 4 speed stick, especially on engines that had flat torque curves.


As a side note, we ran 6 runs last night to see what the difference was between locked and un locked, and found indeed be got better 0-60 times unlocked (1-2 tenths quicker).





The saga continues..http://www.dieselplace.com/forum/smileys/Geek.gif

Apples and Oranges. Your past experience was with gas engines. Diesels are a whole different story with totaly different torque characteristics.

GSXRTURBO1, I politely disagree.. Our blown alcohol motors are very similar to a diesel torque curve-extremely flat. Torque converters multiply torque when not locked, and if put together correctly (efficient stator designs, pumps, turbines) it doesn't matter if its behind a diesel or gas or alcohol motor..http://www.dieselplace.com/forum/smileys/Cry.gif

I'm in the unlocked is faster camp. Strictly from a torque multiplication view. However, if you are making enough torque to blow by the fluid coupling/cavitate the unit then.........


Lock it and Rocket!

All I can tell you is that with a hot tune and a Suncoast tranny it runs faster locked. I always ran locked on my stock tranny too.


WAY faster. I run the exact same tunes in regular as I do in tow/haul. Last time I was at the track I forgot to turn on T/H on one of my 1/4 passes. Same good launch, good 60' time and I went through the traps at 13.5. Activated T/H and went back to the staging lanes and ran the usual 13.1 pass.


I have tried it many times with many different combos and T/H was faster every time. I have more than 100 1/4 mile passes on the truck so I know what works for it. Each truck is different so I guess it could go either way. http://www.dieselplace.com/forum/smileys/Confused.gif

I went out for some 1/4 mile runs last night and consistently did better with the t/h on by 2-5/10 of a second. For some reason though, running without the t/h on always "felt" faster, but it wasn't. I guess it's just in how and when the Suncoast shifts in normal and t/h.


I made the first ten runs with it off and had the tranny up to 300 degrees so I had to sit for a bit waiting for it to cool down. Turned the t/h for the remaining 13 runs and the tranny never exceeded 260 degrees.

IWith a modded trans or a higher HP truck, T/H mode might be better, but if your trans is stock, you might as well be rowing a six speed





I can shift my 6 speed pretty quickly...:)

IMHO


If you have a big program in your Duramax and you are dialed in(especialy with nox) you will run faster without torque multiplication. Bad Ass diesels do this kind of stuff. Anything short of aforementioned diesel will not run as fast because it needs torque multiplication for a while. I say for a while because a diesel does not need it as long as say a big block to get it into the torque sweet spot. The diesel will maintane it's torque sweet spot because of brute force( and of course it is so coolhttp://www.dieselplace.com/forum/smileys/Approve.gif) Track conditions also play a big part in wether you run t/h or not. Everyones truck is different and does different things so there is no set rule.


mike

There is a very big factor here that everyone is skipping over. Once the TCC is locked, line pressure in the Transmission drops to 150 - 160 psi in a stock transmission. So if your running enough power to cause slipage you only make it worse in Tow/Haul by locking the TCC in second gear!

Steve


What about a transmission with a trans-go shift kit ????

There is a very big factor here that everyone is skipping over. Once the TCC is locked, line pressure in the Transmission drops to 150 - 160 psi in a stock transmission. So if your running enough power to cause slipage you only make it worse in Tow/Haul by locking the TCC in second gear!


Good point!


I hate it when I forget the basics! A mind is a terrible thing to lose!

With a stock trans/converter if I don't use tow/haul I GAIN .3-.4 in the 1/4. Meaning with tow/haul on my times are consistently 14.40's and with it off I am 14.70's-.80's. This is with juice/***. stock trans. So It makes a big difference!!!!!!!

With a stock trans/converter if I don't use tow/haul I GAIN .3-.4 in the 1/4. Meaning with tow/haul on my times are consistently 14.40's and with it off I am 14.70's-.80's. This is with juice/***. stock trans. So It makes a big difference!!!!!!!


Yep! http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

I have only run at the track once and made three runs. the one in tow/haul was 43 hundredths slower the the two I run without tow/haul.


I have run 60 times or more using the G-Tech Pro. and every time that I tried both ways, the runs without tow/haul engaged were faster by at least 25 hundredths.


Not all runs were 1/8 or 1/4, as some times they were 0-60 or what ever, and some times they were upto limp. And I have used Propane, PowerMax 145, Juice 90 (Old), Stealth 135, and Predator, and stock. It has never mattered what type of power add on I used, running in normal mode (Non tow/haul) always gives the best time. This is with a stock and withering tranny.

Tow/Haul would be better. Without the converter locked, you will generate tremendous heat. With T/H the converter is locked in 2,3,4 and 5 gears. In normal mode it only locks in 5th gear. It would be better to run in T/H, especially if you have a box. I also think you would run slightly better ET's in T/H mode.


If your tranny is generating tremendous heat with just a few 1/8 or 1/4 mile runs, then you need to have it checked, or put better fluid in it along with the deep pan.


In the nearly 60,000 miles I have put on my truck, I have seen 200* a total of two times. And I have run the living $hit out of it at times.

Just a thought, but could the disparity in times be the result of different "training" of the trans in tow haul vs. <st1:City><st1:place>Normal</st1:place></st1:City>? If someone routinely "races" and drives hard in tow/haul, I would think it would do much better on the track in tow/haul. But if tow/haul is only used for *real* towing and at the track for quarter runs, with most "playing" (and therefore training the Allison to race) in normal mode, then the Allison is going to perform less than optimally at the track.

Does that make sense?

You guys that say you are faster inT/H are saying that the Duramax needs no quicker turbo spool up. If that is true, you are better off with something like a Lenco trans. The torque multiplication in the converter in the Allison (Duramax only) is not that at all. It is there to let the turbo come up faster. The Duramax with a program does not need torque multiplied, it needs spool up quicker.


mike

Tow/Haul would be better. Without the converter locked, you will generate tremendous heat. With T/H the converter is locked in 2,3,4 and 5 gears. In normal mode it only locks in 5th gear. It would be better to run in T/H, especially if you have a box. I also think you would run slightly better ET's in T/H mode.


If your tranny is generating tremendous heat with just a few 1/8 or 1/4 mile runs, then you need to have it checked, or put better fluid in it along with the deep pan.


In the nearly 60,000 miles I have put on my truck, I have seen 200* a total of two times. And I have run the living $hit out of it at times.





I think the sump temperature is not a true indicator of how much heat you may be generating. The sump temp is an average of all the fluid in the trans, but you may have localized areas that have a much higher temp then the average sump temp.


Also, this is a quote from Mike L. in another post:





It is not a good idea to really beat on your Ally before you do the upgrades. You will put a tremendous amount of unecessary heat into the trans and start hurting things that would not normaly be hurt. I have had trucks in my shop for Transgo and converter and wound up doing a lot more parts replacement. Be kind to your Ally, it will cost you less.


mike





Here is the post:


http://dieselplace.com/forum/post_message_form.asp?mode=quote&amp;PID=93352&amp;FID=36&amp; TID=8156&amp;TPN=2

You guys that say you are faster inT/H are saying that the Duramax needs no quicker turbo spool up. If that is true, you are better off with something like a Lenco trans. The torque multiplication in the converter in the Allison (Duramax only) is not that at all. It is there to let the turbo come up faster. The Duramax with a program does not need torque multiplied, it needs spool up quicker.


mike








Very interesting

Seems to me that it varies with the power level, and weight of vehicle. Bigger power just seems to push the converter stall/fluid coupling up too high yielding very little RPM drop. This helps some trucks, and slows others down.





I run T/H and it is better, but it seems to me the Quad 215 on it's own likes it unlocked.

Kennedy


Are you saying more horsepower likes locked (looking at your sig)? If so, thats what I said in my answer above. The faster you spool up the turbo, the more power you make, the less converter slip you want. Now, we have the stock guys and the moderate program guys; this info does not hold true for them. I am running a 30 hp TTS program (Diesel Tech is still pissed at mehttp://www.dieselplace.com/forum/smileys/HiHi.gif) and i run faster without T/H. I asked Steve Cole this question when he was racing the TTS/Transgo truck and he said track conditions dictated wether he used T/H or not.


mike

Seems to me that it varies with the power level, and weight of vehicle. Bigger power just seems to push the converter stall/fluid coupling up too high yielding very little RPM drop. This helps some trucks, and slows others down.





I run T/H and it is better, but it seems to me the Quad 215 on it's own likes it unlocked.








I think the Quad 215 programing is weened in T/H Edited by: JRmac

It seems to me that we are blowing through the fluid coupling in the converter when unlocked. Sure the revs come up fast, but there is next to nothing for RPM drop on the upshifts. I believe a LOT of our HP is being wasted in the unnecessary creation of heat energy.


BMDMAX had a track day yesterday, and may have some details about locked/unlocked...

I ran some test and tune yesterday playing with different combinations. Traction was really challenging yesterday and was the main problem even with the 94 degree heat. Gotta love the cooling system on the Duramax, engine temp never topped 194 degrees and tranny temp never went above 180.


I did revisit the whole locked versus unlocked scenario. Same module, program or stack on my truck all ran .1 to .2 tenths FASTER locked versus unlocked.


I was impressed with the VA 200 + that JK has tuned up, it ran a solid 13.5@101.4 all by itself. It shifted well and pulled hard all the way through the run. I ran the new Quad 225 tune as well. It ran well also, much quieter than the older 215 tune. I drove home from the track with that tune on the truck as well. It was nice driving it for a couple of hours, no rattle or surge whatsoever. It ran a 13.6@100.4 in the 1/4. I did find that I could not stack it with the other usual suspects due to burst or timing problems. I think they would have both been a bit faster yet with a stronger launch, those were both with 1.9 60' times. Rather cool though for a single box. http://www.dieselplace.com/forum/smileys/Cool.gif


I have a vid of the VA and new Quad runs if anybody wants to see them in action....

BMDMAX;


It was nice finding a web page where I could download at a good speed. 519KB/Sec That`s about 1 min 21 sec for a 53.1 Meg file.


I havn`t looked at any of the videos, I was so excited about the fast downloads.http://www.dieselplace.com/forum/smileys/Big Smile.gif


I guess that`s why I spend $45 a month for Roadrunnerhttp://www.dieselplace.com/forum/smileys/Cry.gif


To get back on subject!http://www.dieselplace.com/forum/smileys/Clap.gif


It looks as if it depends on the truck and the amount of added power as to which is best. As I stated before, Mine runs faster in normal mode as apposed to tow/haul mode this is with 145 hp boxes or smaller.





BMDMAX; You really go all out on the production of the vedios. Nice work!http://www.dieselplace.com/forum/smileys/Clap.gifEdited by: hdmax

Mike,


I am pretty happy with my web hosting provider. They do a fairly good job with their bandwidth and servers except for the occasional problem with the site editing tools.


I was going to put the vid up last night of the VA and Quad runs but the editor was out. It's only 8Mb so it should be a bit easier to download.


The launches are pretty cool and you can hear the truck going all the way down the track. I never thought it was that loud but it sounds pretty cool. I will get it uploaded tonight when I get home. http://www.dieselplace.com/forum/smileys/Approve.gif

Mine runs the same either way, with the Six-Gun/speedloader.


15.25 is the best I've ever run with it (level 6). This is with the Banks exhaust and K&amp;N intake system.

Went to the track yesterday. This time I ran exactly the same whether or not I was in tow-haul. My truck is heavy, probably close to 8K LBS with the shell, bed kit and about 4-500 lbs of tools. In any event, at LACR (3000 feet of elevation, but we tested the air and found we were at 7500 feet that evening due to humidity and low barometric pressure) I ran 15.83, 84.02mph with tow haul and 15.81, 84.41 mph without tow haul. slightly faster 60 foot and 1/8th mile non tow haul though. I would launch at dead idle without any boost.


There was a ford f250, 2wd, 4 door, non dually, no shell, etc. with a Banks 6 gun and 4 inch exhaust running 15.75 at 88.5 mph.


Not sure if my 15's are a result of being super heavy or bad air that evening or both. should they be quicker?

A little bit of brake stall should make a nice difference.


Just curious what you do to pass the time on a slow run like that as compared to the times in your signature???

John, I had my DVD player on durning the run, watching Austin Powers.