95' Junker Drag Truck

I could be mistaken but as far as I known the only downside with the 215 pump is the shape of the helix/spill port retards timing 2-3* at high rack travel.
 
The only power change made to the truck since last time out is the addition of 5K governor springs. I made it to Las Vegas Motor Speedway tonight for street legal drag racing. I made two good passes and then the track went away quick!

These runs were made on some bald 285/75/16 Wrangler MTR's with Kevlar Sidewalls (The offroad racing version) at 25 psi. They won't let you run non-DOT approved tires on street legal night so this was the best tire I had available. Finally got into the 12's on street tires!!!

Timeslip8-12-11.jpg


I hot-lapped the truck and made 6 back to back runs because the staging lanes lines were pretty short. (3) 12 second passes and (3) 13 second passes.

On my 6th and final pass, I blew up two boots just a few feet before the finish line. I think part of the problem is hot-lapping the truck because the charge air pipes get really hot and these cheap silicone-intakes.com boots have polyester reinforcing cords that don't deal well with heat.

These two boots should be easy to fix before the Weekend on the Edge NADM event up in SLC.

BlownBoot2.jpg


BlownBoot1.jpg
 
I also was able to get some boost numbers from the primary atmosphere HT4B turbo.

A couple of numbers:

Run 1: He351 stock internal wastegate opening pressure (about 24-26 psi)
HT4B - 40 psi
Total - 68 psi

Run 2: He351 internal wastegate with boost elbow set to an unknown but higher than stock setting.
HT4B - 42 psi
Total - 70 psi

Run 3,4, 5 & 6: He351 with boost elbow set even tighter, probably around 40 psi setting.
HT4B - 45 psi
Total - 78 psi

I find it interesting that tightening the internal wastegate on the top He351 turbo, which should drive it harder, actually makes more boost in the coldpipe feeding it, that is exactly backwards of other claims I've read. The only explanation that I can come up with is maybe my current AFC setup needs 75 psi boost to enable full rack travel so the added boost is unlocking a little bit more fuel. When I tested on the bench, it seemed like 60-65 psi was full travel with the stock 180 pump GSK spring installed in lieu of the stock AFC spring.
 
Last edited:
The truck handles much better at speed thanks to the new-to-me used steering gear that I picked up cheap.... Thanks Riviera!!!


The truck had a lot better traction tonight. Part of it came from the better than usual track prep because they had pro test-n-tune session earlier in the day.
The other part of the traction equation came from my modified traction bar setup. I added a bracket and two lower holes under the rear axle to help get the bar angle more aggressive. All of my research on caltracs has led me to the conclusion that lower mounts in the rear coupled with the top hole on the front mount makes the most violent hit on the rear tires. As long as your shocks are good enough to prevent too-much separation too quickly (that makes it bounce) the steep angle is what it needs.

On my fastest two passes, I left at a conservative 3-4 psi boost and only had to lift immediately after the 1-2 shift. I guess I need to manually lock the converter after the shift when running street tires because this tranny shifts hard enough to break them loose on the 1-2 shift. This latest traction bar modification made a nice improvement in traction.

Caltrac1.jpg


Caltrac5.jpg


Caltrac4.jpg


Caltrac2.jpg


Caltrac3.jpg
 
So when is the second caliper in the rear and et radials going on? 116-117 is getting it done man that thing is going to rull when you put the power to the first 1/8th mile!
 
add a strap across the back of your brackets to keep them from folding when you do get slicks....
got into the 12's on street tires my eye, you obliterated that line!
bring a couple extra boots with you to nadm... just in case
well done will!
 
I also forgot to mention that the new tweaks on the traction bars really helped with wheel spin on the street. I can get it to hook up WOT at 45-50 MPH now, before it would always spin whenever I went full throttle up till about 70-75 MPH on most roads. I still have to baby the throttle from a dead stop and/or normal street driving, but there is noticeable improvement traction at all speeds.
 
I made it up to the NADM - Weekend on the Edge Event but after a flat tire and a few other mishaps on the drive up from Las Vegas, I was too late to enter the Quick Diesel 12.0 index class so I ended up doing some time only runs.

First pass was really slow, the power came and went the whole way down the track like it had a fueling issue but I couldn't figure it out. Boost went from 80 to 60 psi and back up to 70 two times during the pass.

13.09 @ 110 MPH.
[ame="http://www.youtube.com/watch?v=YWGGC99AvM0"]http://www.youtube.com/watch?v=YWGGC99AvM0[/ame]

You can actually hear the slicks screech for a second just before the 1000' mark when the fuel kicked back in.

After checking things over in the pits, we couldn't find any fuel leaks or broken boots so I figured it must have had air trapped in the lift pump system or something related to my broken feed line the night before. Anyway, I went back and ran again with no changes to the setup:
12.91 @ 108 MPH
[ame="http://www.youtube.com/watch?v=o2Ja5dvE98c"]http://www.youtube.com/watch?v=o2Ja5dvE98c[/ame]
After this pass, I was really scratching my head and decided to pull the fuel sending unit to see how much fuel was in the tank, sure enough, it only had about 1/2" of fuel in tank maybe 2-3 gallons in the stock 34 gallon tank, needless to say, that was my fueling problem.

I bought 5 gallons of fuel from Wide Open Performance and went for another run. Truck ran much better and was charging pretty hard till just before the 1/8th mile where it surprisingly nosed over and lost boost once again. When I stopped to get my time slip, they informed me that I had sprayed fuel down the whole track and that i need to get it fixed before I run again. Anyway, the low pressure feed-line from the factory filter to the P7100 pump inlet had bust open at the brazed joint where the hardline transitions to the banjo fitting. This was my best 1/8th mile trap speed to date but no where near my normal 117 MPH 1/4 mile trap speed due to the burst feed line.

12.63 @ 113 MPH
[ame="http://www.youtube.com/watch?v=-Aj4I7Kk0MU"]http://www.youtube.com/watch?v=-Aj4I7Kk0MU[/ame]
 
I did rack the barrels, but kept the same DDP delivery valves. I will add the full-cuts, but I was afraid I could possibly have fueling/idling problems and i decided it was prudent to change one thing at a time. This pump idled and ran fine with the stock 240K mile non-racked barrels, and now that it's racked, this 160 pump is actually a little smoother and idles fine.

When I get the feed line replaced this week, I'll go to the track and make a couple of good hits before the full - cuts.

On my third and final pass, I ran 94 MPH in the 1/8th, which is the fastest I've gone in the 1/8th but the broken fuel line quickly dropped power on the top end and it only trapped 113 MPH. According to feedback from other racers, the line started leaking in the burnout box so it could have had low lift pump pressure as soon as it came up to full boost around 150' out where the smoke cleared up.

I can't give true feedback on the home-benched/racked barrel pump until I get steady feed pressure.
 
Last edited:
I saw your truck at weekend on the edge but couldn't find you to talk to you. That thing is sweet! Very cool budget truck
 
I assume you don't have a fuel pressure gauge? What's your best 60 ft time? If you could get it down to a 1.9 it would slash those ETs.
 
You must log in or register to reply here.
Back
Top