time to see what 60# injectors will do.. going to add another 3-4 psi gradually... from 10.5 now..

Installed the EGT gage tonight ... no melt downs please...

So, let me see if I understand. You can't hook it up until after 50 mph,and for the next 2 seconds from there to 100 or so you have to drive like there is an egg under your foot and your plan is to add more boost. Didn't you have trouble with traction on the dyno last time? Like it couldn't keep up? Will your therapist be present at the dyno test?

Hey, good luck and chain that sucker down! Show us pics. Beater

Beater,

Your too funny. I'll be looking for a boost controller over the winter to manage the hook up problem. I'll be running street drag radials today to help with the traction issue. If all goes well I'll make the last session at the track tonight right off the dyno.

Good luck and be careful! We're not done with you yet. You are truly a pioneer! Beater

EFI,
Hope you have installed more than a lap belt in that truck! Maybe over the winter you should work on a roll bar/ cage. Tom

Good luck and keep the tire side down.

Results?

We found the torque limit on a heavily modified 4L65E....... weird failure mode - the output shaft housing broke. I think the rest is OK - it'll need a tear down for inspection.

Delta from last year +30 RWHP, +70 LB/FT rear wheel torque... still lots left in to tune up. Run 5 came to a quick halt. My guess is another 30 - 50 HP just with the tune. Boost is still at 11 psi (same as last year).

(last year 480 RWHP and 430 Ft/Lb) Only change from last year - changed the intake cam CL.

With a billet main cap girdle and *MORE* drivetrain capacity no problem to make RW 800+ HP at say 16-18 PSI which is still low compared to some other engines at that power level.

Wow, those are truly impressive numbers. I don't know how deep you are invested in the 4L65, but it may be time to consider a 4L80e.

Sorry you broke stuff, but as 56er says those are impressive numbers especially with some still to go. I guess you missed the race night. Beater

All of this has me torn a bit, on one hand I'd like to find the max power of this engine/combo. And on the other hand I'd like to not have to work on the truck next summer and enjoy it.

Like to take it of the Car Craft National next year and that can't happen without solid reliability. Lot of empty miles between here and there. So I might finish the tune and then back the power off by dropping the boost to 10 psi.

I agree the real fun is driving not wrenching, at least some long drives between wrenching. Have some fun with it. The dyno will be there. It'll make more power when its broken in.

"I can quit anytime I want, I'm not addicted!" I'm going to say it once again: build the 4l80. Boost is just mechanical heroin: there is no going back.

I had the boost knob ready to turn.... Agreed that the temptation is there.....

When stock,,,the 4.3 Syclone runs 14 psi.Mainly because the heads are restrictive.

W/a smaller tubo,it only made 386 HP & 550 ft lbs of torque.
21 psi.
Only makes power to 4400 rpm = weak a$$ camshaft.
It goes to show you that a great flowing head can do on the 4.2.


MBHD

Man, I feel your pain. Went out Friday to test and did a huge wheelie and torn up the front suspension. O-well the crowd loved it Just when you think you got it figured out you break someing or tear something else up.

Any video?
Sorry bout the truck.

MBHD

Let's get some more info on the failure mode. As you mentioned, it's weird for the output shaft housing to go. Didn't you already build up the 4L60E? I wonder if something else is in play here (manufacturing defect, out of balance driveshaft, etc). Any pics of the failed part?

I have seen many Powerglide output housings twisted inhalf when used with a Transbrake...most guys around here do a lot of overlay welding inside and out around the mounting bolts and around the tailshaft support. Seem to help the problem..

What sort of driveshaft angles are you running? To develop a side force on the output housing requires that the output shaft and the driveshaft be at an angle. (You don't seem like the type to have installed it with an excessive angle...) Is it possible that under heavy load when the chassis rises the slip yoke is pulling far enough out of the output housing to allow centrifugal force to throw the yoke sideways? If so, it seems that the intitial force would be amplified by the engine torque to create a huge sideways force.

Interesting thought - IDK enough about driveline stuff to say Y/N, but it's worth looking at.

Solid tranny mount, rubber engine mounts?

I've never had any vibration issues from the drive train even at the top end of the track (109mph).

Pinion is down about 4*, there is a slight offset between the transmission and 9" yoke but its like 1* or less. Shaft is about 60" long from memory.

Rubber mounts around.

From the tailhousing mount to the output seal the housing came apart in 3 chunks.

We had a bit of rpm surge occurring and I'm now thinking that it introduced lateral thrust somehow. The truck was chained down using the axle tubes so its possible that the suspension could have moved a tiny bit but not much.