7875 + 5.9 + E85 + Megasquirt

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I took the car to the track last week and have a new challenge. I made three runs total, all shitty. First two were 7.70s at about 95mph and slow short times. I pegged the shift light the entire run and the log showed I was hovering around 6300 rpm the whole pass. This was at about 12 lbs psi. So on the last pass I turned off boost control and just ran off wastegate spring which was around 7 lbs psi. I went slightly faster, 7.60 but dropped about 1mph and only hit 6000rpm. I’m either blowing thru the converter or the trans is slipping. I changed fluid and filter, adjusted the bands and it’s about the same on the street just running off the waste gate. Next step is to probably drop the trans and rebuild and send off the converter or get a new one.
 
That sucks! How did the fluid look? If it’s happening in every gear I would think the rear clutches might be toast. I’d be interested to hear if it’s the converter as I don’t really know the symptoms of that type of failure…
What have you done to build the trans, and what valve body?

Any improvements in blowby?
 
turbovan said:
That sucks! How did the fluid look? If it’s happening in every gear I would think the rear clutches might be toast. I’d be interested to hear if it’s the converter as I don’t really know the symptoms of that type of failure…
What have you done to build the trans, and what valve body?

Any improvements in blowby?
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The fluid looked great, smelled fine. It was practically brand new anyway.
The pan had a little bit of junk in it but nothing crazy. It still shifts firm going through the gears but IDK. If I’m going to pull it to service the converter I think I might as well pull it apart and inspect everything and replace clutches, etc. I bought it already built by somebody else. It has a RMVB in it. An old TCI I think and its been a great trans so far.
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I’m with 85glht. When you take power out and pick up .3 and only lose 1mph that screams converter is too loose. I’d rather it be too tight and just try to smack it in the *** on the 2step to overcome it trying to drag the motor down that way you’ll have good slip numbers in high gear.
 
turbovan said:
Any improvements in blowby?
Click to expand...
Yes the oil catch can coming off the pan seems to have done the trick. It’s also a great heat vent from the engine. There’s some serious hot air venting out of the engine through it.
 
Sounds exactly like you’re blowing through the converter. What fluid was in the trans? You could try hygard and see if it tightens up the converter if you just had atf in it.
 
New converter installed. Got this from a buddy who had it as a spare. It’s a Circle-D supposedly and was built for an oddball — LS turbo mated to a 727 in a Dakota. It’s a little tighter than my PTC and has much better street manners and flashes to about 3200rpm. Now that I’m able to couple the HP to the trans and back to the rear tires, the difference is incredible. Feels like I was slipping 100hp in the old converter. Oh, I've been using Hygard (Lucas equivalent) @TT5.9mag for a while now on my trans. I love it. Just add enough ATF to give it a watermelon juice color so you can read it on the dipstick.
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This was earlier today. 3rd gear, rolling into boost on the street. The old converter was blowing right past this and hitting as high as 6300rpm. This one is holding steady. Can't wait for next track day. :)
Also my new Ford Contour dual electric fan and PWM controller is working like a champ. It's a hot and humid 96F today in S. Florida and cruising temp stayed below 180 and creeped up as high as 190 at stops.
5300rpm_9.3psi.png
 
subcom said:
This was earlier today. 3rd gear, rolling into boost on the street. The old converter was blowing right past this and hitting as high as 6300rpm. This one is holding steady. Can't wait for next track day. :)
Also my new Ford Contour dual electric fan and PWM controller is working like a champ. It's a hot and humid 96F today in S. Florida and cruising temp stayed below 180 and creeped up as high as 190 at stops.
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Excellent!!
 
Awesome news!
9.5 converter? Is it flashing to 3200 under boost, or is that stalling it on the brakes? I’m curious because my 9.5 is supposedly setup as tight as possible; brake stalls to around 3200 and flashes to around 4800 at full boost.

I, again, know very little about converters. Is this something that wore out slowly over time as opposed to breaking all at once? I’ve been wondering what’s holding your new build back as I believe the old motor/turbo went 109 in the 1/8th?
 
The electric fan win is great too! I was a bit confused why my car was staying cooler than yours in similar temperatures(minus humidity) even though my block is half filled.

What are you using for a pwm controller or how is that set up?
 
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