turbo lemans

my buddys th400 does that he said its because it has a non reversing sprag he hates it also but the car runs 10.80s so his its not slipping for sure

jtotheizzo

Well took her out to the track last Friday. First and foremost drove it there and back so once again no complaints.

On the way to the track it became apparent the transmission still wasn't right. Third gear just never felt like it engaged fully but I ran it anyway.

Ran a new personal best of 11.54 but 2nd and 3rd are pretty much gone. I get about a 300 RPM drop from 1-2 and it practically goes on the limiter from then on. No more whining from the trans with the new filter but it just doesn't seem to hold.

I am not sure if it is worth trying hygard at this point or if I should just tear it down. It works better when it is cold but even cold it takes a lot more rpm to move in 2nd and 3rd.

Forcefed86

iTrader: (4)

Def wouldn't bother with hygard. I would check pressure while it's still together and in the car. May give you an idea whats wrong.

Do the TH400's have the input shaft bushing? (sometimes called a stator support bushing) If the converter was built to run without one, running one can cause issues. Don't think it would cause it to slip that badly, but something to look at. Removing it tightened up my converter alot and cut way down on the fluid temps.

jtotheizzo

Agreed on the pressure, I just ordered a gauge since I should use one for the rebuild anyway. I will post up when I have numbers.

I am not sure on the bushing. When\if its time for the rebuild I will verify and discuss with the converter builder.

jtotheizzo

Update time:

I put a gauge on it and took the following readings:



Then for the next month I had to work on the 'Honey do' list. Painted the house, worked on the yard, worked on the boat, etc.

Now it is time to get back to it...

Pulled the trans last weekend and this is what I found.

Intermediate clutch pack:


Direct clutch pack:



So needless to say the Directs are smoked and the Intermediates were on their way. Incidently the forward clutch pack looked great.

The transmission was supposed to be a fresh rebuild and from what I can see it is but it was all stock parts.

So I have ordered the stage 2 kit and when it gets here I will rebuild this thing with all the usual tricks, more clutches, 34 element sprag, dual fed directs, bleed hole in direct, 3rd gear cutback, converter circuit restriction, etc.

Hoping to have it back together and terrorizing the streets within a month.

Forcefed86

iTrader: (4)

Trans and converter are everything! I bet it will be a while new car...

jtotheizzo

Well it looks like it is time for an update.

I got the transmission rebuilt.






Then reinstalled.


Then to the track:




Still not happy with this run. We had a tough day at the track though. It was cold and rained on and off. Ended up spinning the tires 3 out of 4 runs. ^This run I got out of my routine and accidentally left the car in drive. It was a pretty lazy pass on about 11 Degrees of timing and 14 PSIG launching on 3 PSIG.

I am still not unconvinced the trans or converter is slipping in high gear. I calculated 20% slippage at the stripe. I have since switched to hygard and hooked up the kick down switch. (there was all sorts of debate if you need this or not I decided it cant hurt and wasn't that difficult to add.)

I will say it again though... Drove 80 miles round trip to the track so it was a good day. I would just like to see a 10 sec slip before winter hits. We have one more track day left this year. Here is to hoping it doesn't rain. I am also thinking about throwing this on the dyno to get it dialed in soon as track days have been few and far between this year.

Forcefed86

iTrader: (4)

1.6X 60 on 3lbs is pretty good! MPH isn't horrible for a heavy old Gbody! But I agree somethings still a little off. What kind of RPM are you turning at shifts? at trap?

I'm assuming if it shifted itself you weren't revving it very high? The converter will couple more with added RPM. Shifting at 6k or under I'd regularly see 15-16% on the cheapish converters with my buick.

jtotheizzo

I was a pretty big fan of that 60 I wont lie. Car is about 3600 with me in it. It shifted automagically at 5700. I went through the traps pretty much on the limiter at 6000 rpm. I only saw about 200 RPM drop on the 1-2 shift and couldn't see the 2-3 in my data. I am all ears if you think I should be shifting at higher RPM. But I haven't bumped the limiter due to being on a stock truck cam.

Forcefed86

iTrader: (4)

Defiantly on the downward slope by 6k on the factory cam. Can’t imagine it would help much to rev it higher. Shifting at 6k or 6300 or so may help if you have the valve spring for it.


I’d talk to the converter guy. I don’t want talk trash on his product that I know nothing about. But if your pretty sure your trans isn’t slipping anymore it’s the next logical step. Though I know pulling the trans 10x a year isn’t fun. I think you’re on the right track with the Hygard. Could even try a little taller gear to take advantage of all that slip. Did you see the trans fluid temp?


I had issues with the typical larger converters needing big RPM to couple well. I’m sure there are many acceptions to the rule these days with all the custom CNC stators and such. I’ll say that generally you need a smaller converter designed specifically to couple at lower RPM. These also generate more heat which is a pain on a street car and aren’t cheap. Looking at around $1000 shipped.

jtotheizzo

I am running the TFS version of the PAC 1218's. I can certainly bump my limiter to 6100 and try shifting it at 6000.

No I haven't added a trans temp gauge yet but I will likely do so soon. I had some other challenges I needed to resolve first. For example I was throwing belts so changed to a manual tensioner.

I am interested in seeing how it does on the Deere oil. I am not 100% sure it isnt slipping though I wouldn't know why if it was. My pressures look good, I upgraded everything inside that trans while I was in there. I am running an auto valvebody that does drop off pressure in third that is why I am hoping that hooking up the kickdown helps with that. I plan to put the pressure gauge back on it and see what my pressures look like on Hygard and if they are staying higher in third while on the Throttle. If not I may take another swipe at the third gear cutback mod. I attempted it and my trans shifted all sorts of goofy. I know they say that can be overcome with governor mods but I can help but think I am not making enough power to need mods like that.

This winter I will start the build on my 1999 TA so I am not sure how much more I will actually put into this car but I may swap back to the stock converter to see if it gets any better. I definitely would like to see some better numbers before I put it up for sale though.

Thank you as always for your feedback!

Forcefed86

iTrader: (4)

Those springs should be fine, I’d bump the limiter to 6500 and try shifting at 6300 or so. Guys are revving these motors out past 7k thru the traps with zero issues on the factory hardware and bottom end.

If pressure is dropping in third it could be slipping. Fluid temp and look/smell should let you know if its slipping.

3 window

iTrader: (1)

I think the kickdown being hooked up will let the trans shift later automatically rather than depending solely on the governor. Should make a substantial difference. Only a 200 rpm drop and no noticeable drop into third is a problem too. Seems way too loose for the setup. All the times/speeds seem to jive. The sixty is typical of the overall ETs and so are the speeds. Just seems down on power over the entire course o te run. I'd raise the limiter more than 100 over your intended shift point. If it's bouncing off the limiter, it's killing the run. Seems as though it's not loading up the setup enough to make power. Seems it's only making boost because of the rpms you're turning not the load on the setup.

jtotheizzo

Thanks I certainly appreciate your thoughts. I think it is high time we put this thing on the dyno and find out for sure. I will admit it doesn't make boost very well in first. If I don't 2 step it I get about 9 PSI at the top with a gradual rise. As soon as I click it in second though it goes up to 14+ and holds to the end of the run. I always attributed that to more load in second and third gear. If I launch it on the 2 step at 0 -3 psi it easily makes 12-15 in first.

I do have another converter to try and may just do that. The fluid I pulled out wasn't burned but I was surprised at how much friction material was in it.

3 window

iTrader: (1)

I would still think the car should mile an hour better than a buck twenty at 15 psi with 11 degrees. Not being a tool, but have you checked the throttle at WOT? Just strange that everything jives as far as times go but it's not running the numbers. Not sure the dyno would tell you anything really. Can't remember, is it a stock cam? If not, was the cam degreed in? Does the converter flare up when you take off or is there some load on it? Does it sound like a snow mobile going down the track? Id think you should be about 10 mph faster right now.

jtotheizzo

I too expected it to trap about 130. I have checked the throttle and for sure it is going all the way open. My thought on the dyno is that it will rule out tire spin(was having issues all day). We just had a hell of a day at the track and only got one clean run in. I was hoping to take that factor out of the equation.

The cam is stock and the only change I made to the valvetrain was to add springs.

Here is a video of that run:

I certainly can feel and see the 1-2 shift but on the 2-3 the shift light stayed on confirming little to no rpm drop and it certainly did sound a little snowmobie-lish then.

I will add that it was pretty rich (around 10.5) on that pass and it was pulling timing due to IAT's (115*ish). I pulled fuel and resolved the timing issue but never got another clean run. (tire spin)

bigmandengo

iTrader: (21)

For comparison sakes, my stock cam 5.3 at 15 psi in a heavier g-body(3800 lbs) runs 125+ with a stock 4l80e converter.

jtotheizzo

Added data to the above video. The Gear indicator is a guess based on the data as well as the Converter slip is simply a calculation also based on the guess of which gear I was in. (I do realize that slip in any gear but 3rd isn't accurate but it is there anyway.)

Forcefed86

iTrader: (4)

Looks like its driving thru the converter or still slipping bad to me. Slow it down to .25 on utube and watch the RPM. Can see the shift pretty clearly. Looks like you shift at 5700 and it only drops 250rpm or so. Then you drive right thru the 2-3 shift.

jtotheizzo

I think at this point I am going to throw that run away.

It is entirely possible the trans was slipping since it was in drive and likely the line pressure was not as high as it should have been. Before the rebuild I was getting 400 RPM drop when shifting closer to 6k.

I have raised the limiter to 6300 and I will reset my shift light to shift around 6k. Running hygard now which has made the car more driveable on the street for sure since it doesn't seem to take so much throttle to get it moving. I also hooked up my kickdown switch on the trans which I am hoping will equal higher line pressure when in drive and WOT. ( I will verify that when I have time.)

I am hoping that these things will give me the best chance at a better run. Hoping for some good weather on the 18th so I can try it one more time this year.