Finally got around to reinstalling my boost gauge and took the truck out for a blast tonight. With my mods including a #4 PSP lower pulley the highest boost I saw was 12#. This is exactly where it would pull to before with a 2# pulley and to make matters worse the truck runs the same ET and MPH with the 4# as it did with the 2#. I also noticed that if I rolled into the gas the highest boost level attained would be around 10psi, would have to slow down to a slow roll and mat it to see the boost creep up and finally reach 12 psi.

I had hoped to be able to run in the high 12's at 107mph but am stuck in the 13.10's @ 105mph with the 4# which is exactly what it ran with a 2# pulley right down to the 60ft's. Any ideas? The $# is noticeably larger in diameter so I know I have the right pulley, the chip has been reburned for the added boost and I also changed plugs to help cure any detonation problems.

I am stumped here and am getting tired of this truck not performing the way it should in my opinion. I was wondering if anyone thought the boost could be venting somewhere??

My mods are listed below.

PSP 4lb lower pulley
JDM Cold air, breather, flip chip, boost bypass
Line valve mod

Best ET was 1.95 60 ft
13.12 ET
105.58 MPH
With 4lb and agressive chip side on the flip chip.


Had run 1.92 60 ft
13.14 ET
104.89MPH
With the same mods except with a #2lb lower pulley.

Please help,

 

Bingo! Lousy 60ft mean no 12 sec runs. To much tire spin bud. Slicks and traction bars should cure your problem.

 

Get some headers too and you'll see some results.

Daniel

 

Weather is a factor you know!!! I wouldn't spend $1800 on an Exhaust system...cuz that ain't gonna help that much...Get some slicks and lighten the BIZITCH up: remove tailgate,hitch, and spare!!!

Chikin@Charter.net
---------------------------
Black '01
Born on 5-3-01
#3603 of 6381
410HP/503ft.lbs @ Normal Temp. w/o N2O
JL Logocaps w/Keychain
JL 3# Lower Pulley
Sean Hyland 2# Upper Pulley
JDM Cold Air
JDM Boost Bypass
JDM/Accufab Throttle Body
JDM Longtubes w/ Silver-Bullet cat-back
JDM Cobra R pump
JDM Eletric Fan
JDM 2” Drop Shackles
PSP 4-Way Autologic Chip ( Tow, Street,Track, N20 )
PSP FactoryTech Valvebody
PSP Deep Tranny Pan
PSP DriveShaftLoop
PSP Truck-Traks
PSP Nitrous Plate
Nitrous Express 50-150 Kit ( Can’t decide which jets to use )
NGK / TR6’s ( .040gap )
Hoosier DOT’s 28 x 10 x 16

 

I would pull the plugs and check them for color to see how it is running, maybe the chip got burned wrong, I know that happens somtimes. I was stuck at 13.1 a while back with stock pullies and when I went to the JDM 2 pound lower, electric fan, cobra r water pump, 373 gears I then jump down to the 12.7's on street tires. I love the JDM electric fan and water pump mod and highly recomend it to everyone. When you race is your truck cool? I have about an hour an 15 minute ride to the track and I always let it cool down from the drive before racing, and I wait atleast an hour and a half in between runs with ice. If you are racing it hot this could be your problem, it really makes a difference with any supercharged or turbo vehicle. With your mods you should be in the twelves in my opinion. So check the above and it would also help to get your 60' times down a little too, if you get down to a 1.8ish for a 60' time you will have your twelve second run. Good luck and don't give up until you hit the 10's.
Bill

 

What plugs did you go with???

 

I'm shakin' my head.......just d/k what's happening--or not happening??? I'm trying though.

If it's not making additional boost, maybe the s/c belt is slipping. There's more 'strain' on it when spinning the s/c faster. Yoy could get a Goodyear Gatorback belt and at least eliminate that possibility. The p/n for my 5lb pulley is 4080680--it was 'tight' so it should fit a 4 lber--if not, drop down to a '670. Btw, if you remove the belt from the s/c upper pulley, try spinning the s/c by hand and feel how 'free' it is.

Hopefully, you installed NGK TR6s or Denso IT20s(gapped from .038-.040")

I d/k where/how boost could 'bleed' off.........

I made it into the high 12s with a 3lb pulley but only after going to M/Ts and removing the spare, hitch, and jack.

Yours is truly a 'tuner's' question.

Dan

 

When I installed various pulleys on my truck I noticed my boost did not increment linearly with larger pulleys. You will make more boost sooner w/ a larger pulley, but you may not make all of the additional boost. Also, each truck will react differently depending on temperature, exhaust, intake, etc. You should see an increase in ET, but it won't be dramatic. You would think a .10 per pound of boost, but it doesn't always equate to that when you add in factors like temps, barametric pressure, traction, etc.

 

12# with a 4# pulley sounds about right tho doesn't it? I mean you don't get a "true" 4#'s the trucks stock put out right around 9#'s of boost(don't pay attention to the factory gauge ) So I would think that is right. Like 99 said you should see more boost sooner

 

With a 4# pulley i see around 11-11.5

It looks like your mph went up, soo the pulley did make additional power.

What plugs are you using? you should NOT be using stock plugs with that pulley!!! Get the Denso IT20's, you will be happy!

Brandon

 

VERY VERY SIMPLE!!!!!!!!!!!!!!

Your 60ft are way off,you need to be in 1.8s and 7s before you think about 12s and these trucks run 8psi stock so 12 with a 4# is right on.Dont worry!Get slicks.I dont now how you can complain when all youve really done is a chip/filter/pully

 

I was wondering if he had his chip reburned for the new 4# pulley.

 

How hot was it? Don't let everyone tell you you can't get into the 12's with that 60', it is possible. I ran 12.93@106.60 2.01 60'. It was about 54 degrees though. Two nights before I couldn't get less than 13.06@105.43 1.99 60'. It was 65 that night. The temperature makes a huge difference. By the way, I know my 60' times suck, thanks!

 

Dude,

You ran a 13.14@105 down here NOW? With the HEAT we've been having? Man, you've got NO Worries!!!!

When the temps get down into the 60-70's in November/December you'll be running MID-12's.

I ran 12.81@105........but I got a 1.82 60'. 3# lower

So it IS possible to run in the 12's with 105mph. You just need 1 good run.

Remember if it ran 105 now in our beautiful sticky 90 degree/90% humidity weather......You'll run 107 or so when it cools off a little.

But for the rest of the Summer.....you're pretty much stuck!

 

Thanks for the replies guys.

First of all I know I have a 12 second truck in 13 second clothing. I run the truck like I drive it on the street, 93 octane, no ice, minimal cool down, 35 psi in the rear tires, full weight ect.

Where I am / was worried is when I went from a 2lb lower to a 4lb lower and didn't pick up much ET/MPH and the boost didn't increase accordingly. I realize it hits harder sooner but was expecting to see at least 13 psi on the gauge, not 12 psi right before gear changes.

The truck only has 7,000 miles and about 2.000 on this motor (old motor was replaced due to excessive oil consumption) so everthing is still factory fresh so to speak. I guess I was just hoping that someone was going to jump in and say, "Dude the boost actuator arm is tweaked", and ta daa I see 107 mph with a 12 second ET.

I decided to make a few changes to the suspension set up and run the truck at Moroso tomorrow evening. I made the little braces for the rear leaf springs, removed the front sway bar, and will adjust the tire pressure down a bit to say 26 - 28 psi and see if I short time a bit better. I will also be installing an electric fan and water pump this weekend and have a few ideas for a homemade powercooler to help out a bit at the track.

I also have an appointment at the dyno with Lamba sensor Saturday AM so I should know if hp is in line soon.

To answer a few questions, plugs are NGK TR-6's gapped @ .038 and the chip was reburned by JDM for the increased boost.

Oh and Bill when I want to run 10's I just jump on the Busa , ran a 10.42 @ 138 the other night in full street trim with a 2.05 60 ft on 87 octane (it likes that the best). Not bad for a 9 second bike as soon as I can cut a nice 1.60 60 ft (it's possible but mentally I wasn't up to the task the first time at the track). Bike is set up to run 9.60's @ 145 mph, too bad the rider wasn't .