95' Junker Drag Truck

I wish I would have thought to PM you. I was in Vegas these last 5 days for work, killing time really. I would have liked to check it out.
 
this is a great build love the budget im in the process of doin one now hope to hit 12s without breakin me
 
I fixed all 3 oil leaks so now the truck is road worthy.

I noticed that the 2.75" to 3" silicone straight reducer on the He351 outlet was migrating a little bit. Since this section of charge pipe sees 75psi, I decided to reinforce the joint. I drilled and tapped a bolt into the turbo's elbow and then welded a bolt to the charge pipe and installed a 5" length of scrap steel strapping.

ChargeClamp2.jpg


ChargeClamp1.jpg


Now the silicone boot cannot migrate and the joint should stay tight.

I then moved on to installing drive shaft loops. NHRA rules require driveshaft loops when you run slicks so I decided to install drive shaft loops. This truck has a two section drive shaft so I had to install two loops. I priced out 2"x1/4" flat stock and it was cheaper to buy a "kit" off ebay with the bolts and pre-bent shape. It cost me $10 per loop kit plus $11 combined shipping so $31 total. I used miscellaneous scrap steel to extend the kits and complete the installation.

DriveshaftLoop003.jpg


DriveshaftLoop004.jpg


DriveshaftLoop005.jpg


The rear loop was a little more labor intensive because the fuel tank hangs down a little lower than the frame rail so it's not feasible to run a straight brace over the to driver's side frame rail.

DriveshaftLoop006.jpg


DriveshaftLoop007.jpg


I used a scrap of unistrut to secure the loop to the bed support rails.

DriveshaftLoop008.jpg


DriveshaftLoop009.jpg


DriveshaftLoop010.jpg
 
I took a couple of pictures of the reinforced stock boots on the driver's side or "cold" side of the charge air cooler. For the upper boot, I installed a small section of 3" pipe so that the high pressure boost doesn't have a large area of exposed silicone to balloon and explode. I then added a few extra t-bolt clamps LOL

Boot1.jpg



For the lower boot on the driver's side, I reinforced the stock boot with 3 layers of duct tape. I found that too many layers of tape become soft and actually slip off over time and cause the clamps to slip. So far, this Junker-engineered boot has held the added boost pressure from the twins.

Boot2.jpg


Boot3.jpg


Picture of the duct taped boot from the underside of the truck:
Boot5.jpg
 
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After adding a bunch of extra weight from the twin turbos, and drive shaft loops, I decided to lighten the front end a little more.

I removed the front sway brace, it weighs just under 30 lbs and sits right up front so it might help a little with the terrible 65% front weight bias of this truck.

I also have been studying chassis setup, and apparently when you remove the front sway bar, it lets the front end roll and twist which in turn keeps the weight more evenly distributed on the rear tires during acceleration.

Before:
Sway1.jpg


Sway2.jpg


After removal of the sway bar:

Sway5.jpg


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Sway3.jpg
 
HAHA i should have bought some stock in t bolt clamps before you did this LOL looks good man hope it all stays together.
 
Man that's some serious "engineering" going on there:p. Cool build though look forward to hearing how it does at the track!
 
Had a chance to drive it in the dry yet? If so what kind of overall boost are you seeing?

I can't recall did you just re-torque the stock head bolts?
 
dvst8r said:
Had a chance to drive it in the dry yet? If so what kind of overall boost are you seeing?

I can't recall did you just re-torque the stock head bolts?
Click to expand...

Yes he just has stock re torqued bolts, he has mentioned it in a few other threads.
 
dvst8r said:
Had a chance to drive it in the dry yet? If so what kind of overall boost are you seeing?

I can't recall did you just re-torque the stock head bolts?
Click to expand...

I tightened the wastegate rod 1 full turn and now boost is peaking right at 80 psi. I have a few days this week to drive it and do a little tuning before the upcoming NHRDA event in Wittmann, AZ so I'll be sure to post updates as I "tune-in" the new turbo setup.
 
One other thing you may want to do before you go racing is add some limiting straps to the front end. Used seat belts work well for this.
 
We do it on mustangs, supra's, vette's, camaro's, ect... Consistently shows better 60's. I'm no engineer I couldn't explain why, I just know from experience it works.

You don't strap them nearly as tight as on the 4wd, still let them have a little droop, to help initial weight transfer, but after that it just seems to slow it down.
 
dvst8r said:
We do it on mustangs, supra's, vette's, camaro's, ect... Consistently shows better 60's. I'm no engineer I couldn't explain why, I just know from experience it works.
Click to expand...

None of the above mentioned have anywhere near the awful weight bias of one of these diesel trucks though. Anything is worth a try however especially something this easy to execute. I would certainly think limiting straps would not be what you want with something already handicapped in transfering weight to the rear tires as one of these barge motored tanks.
 
Now that you metion it I have heard of it. But I don't know If blue is hooking up good enough for it?
 
Lostnwalmart said:
Now that you metion it I have heard of it. But I don't know If blue is hooking up good enough for it?
Click to expand...

I'm up for trying anything on this truck. I watched a couple of videos of my truck back when it was running 14's and it looked like the front end hardly rises. I was thinking it would help to install full length Ram 1500 coil springs in the front end to lower it a little but also let it rise a little more at launch.


A limiting strap is the exact opposite of this, but I'm up for trying anything. I don't claim to know much about chassis setup as evidenced by my 12.7 ET's at 112 MPH.

I do think the smoother power delivery from the twins will allow me to run much better the first 330' of the track and I'm sure I'll pick up lots of ET even if MPH at the end remains nearly identical.

All that I know, is by the middle of the day Saturday, I'll know for sure how well it hooks up and how much power was increased with the twins.
 
I did some more closed course testing tonight.

I tightened the wastegate rod one turn tighter and boost now peaks at 72 psi. Also, after peaking in overdrive around 2800 rpm, boost starts to drop and levels off around 65 psi from 3100 rpm on up. Not sure if the wastegate is doing it's job and letting the top turbo (He351) slow down a bit or if it's not opening far enough and the bottom turbo is nosing over, or maybe the dual lift pump system is not keeping up and the injection pump is nosing over a little.

At any rate, this turbo setup spools great!!! If I stand on the brakes and give it a little pedal at a dead stop, just enough to take the slack out of the drive train but not enough to register boost on my 100 psi gauge, I can floor it as I release the brakes and it will blow the tires off from a dead stop and hit 85 MPH of wheel speed in less than 3 seconds.

On an "open course" I rolled into the throttle cruising down the freeway in Overdrive with the converter locked at 1700 rpm and it makes about 28 psi boost before 2000 rpm, by then the bottom turbo is fully lit and boost skyrockets to 70 psi in about 1 second.

It's kind of cool having a small responsive top turbo and large bottom turbo. Great throttle response and still a ton of top end.

As well as this setup spools, I'm curious to see what it would do on a dyno.
 
the 1500 front springs and looser valved front shocks would probably help the weight transfer
 
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