11.20's -11.30's is this my limit w/ this combo

[bison]

Ok i went racing today. 85 degrees and pretty humid. New mods this year is the BA front mount and fiberglass front bumper. Last year i could only get 26-27 pounds of boost thru the duttneck I/C. Today i was only able to get about 22 pounds of boost and a disapointing 11.70 at 114. The day i hit 11.20 it was low 60's and DA was around 100 ft so it was very good air. I think its time to stretch the spring on the RJC boost controller to get more boost. Or if anyone has any ideas let me know. Thanks

You've got about another .7 -.8e.t. From your best so far. Are you logging anything? Have you verified timing? What a/f? What is the converter flashing to under the highest boost you will run it at? The 218 grind is not ideal for your combo and will peak around 5500. You want the flash stall speed over 5300. What is the converter slip crossing the line? The 61 will continue making power to 32-33psi and 5500 rpm. I went 10.61@127+ with a smaller 60-1 and similar heads with no porting only bowl work and valve job. There is probably .4 in the converter and gearing and another .3 with more tuning. I'd run 116 and a small shot of alky to get the most out of it.

 

[jetmech]

You've got about another .7 -.8e.t. From your best so far. Are you logging anything? Have you verified timing? What a/f? What is the converter flashing to under the highest boost you will run it at? The 218 grind is not ideal for your combo and will peak around 5500. You want the flash stall speed over 5300. What is the converter slip crossing the line? The 61 will continue making power to 32-33psi and 5500 rpm. I went 10.61@127+ with a smaller 60-1 and similar heads with no porting only bowl work and valve job. There is probably .4 in the converter and gearing and another .3 with more tuning. I'd run 116 and a small shot of alky to get the most out of it.

I use direct scan, My chip is a 25/23 extender chip. I have the th350 trans and have the 3rd /4th gear wires grounded so the ecm thinks its in first/second gear. Direct scan shows 25.3 degrees timing at wot, but i started at 22 and went up to 23.75. I have played around with shift points and it seems to run best numbers shifting at 6000. I do drop 1000 rpm on shifts so thats maybe why it runs better numbers. Flash stall, i could pull car out get up on t-brake and see what it goes to, i usually lauch it around 45-4800 but it will go higher, i just never tried it. Converter slip- not that sure what car weighs but there is a grain tower with scales rt. down my block,maybe they will let me weigh car. but i do cross finish around 5300. BTW it is a coan conv. so i can send it out for a restall if needed for 100 bucks versus a 800 dollar ptc unit. Thanks for help on this Bison i appreciate it. Also just using the denso O2 sensor reading low 700-750's during a run.

 

[bison]

I use direct scan, My chip is a 25/23 extender chip. I have the th350 trans and have the 3rd /4th gear wires grounded so the ecm thinks its in first/second gear. Direct scan shows 25.3 degrees timing at wot, but i started at 22 and went up to 23.75. I have played around with shift points and it seems to run best numbers shifting at 6000. I do drop 1000 rpm on shifts so thats maybe why it runs better numbers. Flash stall, i could pull car out get up on t-brake and see what it goes to, i usually lauch it around 45-4800 but it will go higher, i just never tried it. Converter slip- not that sure what car weighs but there is a grain tower with scales rt. down my block,maybe they will let me weigh car. but i do cross finish around 5300. BTW it is a coan conv. so i can send it out for a restall if needed for 100 bucks versus a 800 dollar ptc unit. Thanks for help on this Bison i appreciate it. Also just using the denso O2 sensor reading low 700-750's during a run.

You need to verify your timing. I'd send the converter out so that it drops to 5300-5400 at the highest boost you will run it at. It seems unlikely that hou are making power over 5800 with that combo. Get a wideband So you know where you really are. Chances are your rich too. Some dyno time would help you a lot with this build

 

[jetmech]

Thanks, i will look into your suggestions.

 

[NCTURBOS]

I'd also look into some fresh valvesprings. You've been running those Comp 980-12's pretty hard for the last year or so...


K.

 

[bison]

I'd also look into some fresh valvesprings. You've been running those Comp 980-12's pretty hard for the last year or so...


K.

If thats what he was running with this combo he will be very happy when he gets the correct springs on there and gets the converter nailed down.

 

[jetmech]

Shoot, I've had those valve springs in there for 4 or 5 years since KAI at kn performance did the heads. What is the recomended valve springs these days. I also found a bunch of leaks in the intercooler pipe connections. The t-bolt clamps had some bends in them which was leaking air at 4 connectors. Bison do you sell springs. Thanks

 

[NCTURBOS]

If thats what he was running with this combo he will be very happy when he gets the correct springs on there and gets the converter nailed down.

Shoot, I've had those valve springs in there for 4 or 5 years since KAI at kn performance did the heads. What is the recomended valve springs these days. I also found a bunch of leaks in the intercooler pipe connections. The t-bolt clamps had some bends in them which was leaking air at 4 connectors. Bison do you sell springs. Thanks

I'm thinking it was 2008 when Khai and I were working out of the same shop and you got the heads. I know for sure they're Comp 980's, and they're probably setup on the loose side, IIRC. That's typically what he installs with flat tappet setups, unless otherwise requested differently.


K.

 

[jetmech]

I'm thinking it was 2008 when Khai and I were working out of the same shop and you got the heads. I know for sure they're Comp 980's, and they're probably setup on the loose side, IIRC. That's typically what he installs with flat tappet setups, unless otherwise requested differently.


K.

Thanks i went back in my PM"s and saw 2007 but it may have been 2008 when i put them on. Im going to look into the 981"s, Thanks for all the help guys, hope to get this in the tens this year.

 

[jetmech]

Ok, i put new 981 valve springs in. They were shimmed already from knperformance. I went out 2 fridays ago it was 74 degrees out. Right off the trailer it went 11.32 at 118 at 21 # boost. I still had boost issues and could only get the boost to 22-23# so i started going up in timing my timing went from 21-22 degrees in .25 increments.. i ended up running 11.24 at 119.89. I think i figured out my boost issue. I put 20 psi of shop air into my rjc boost controller with it screwed all the in and my wastegate opened. I ended up streching the spring so now i starting around 23# and can go up to 27-29-#. I will be racing at the MWBC so we will see if i can get this thing in the 10's. Thanks for all the help, I also talked with Coan and they said they cant do anything w/ the 10 inch converter i own but if i bought the 9 inch they can dial that one in more precisely. If i buy a new converter if WILL be a PTC.

 

[Dusty Bradford]

It's slow from 60' to the 660' or something. With those 60' times and 119mph it should run 10.90's. The valve springs were a step in the right direction. I'd look at how long it takes to reach peak boost. I have forced 30psi through a stock neck intercooler and ran 11.0 117-118 but your RJC valve or gate me be letting the boost come in too slow.

 

[jetmech]

I will post up the 60 - 660 times later today. Thanks, it was in the 1.52-1.55 60ft. times on that 11.24 pass.

 

[jetmech]

60ft----1.558
330----4.597
660----7.156 @95.97 mph
1000----9.363
1/4---11.242 @ 119.69mph