Boost level with arp head studs

[rx1 fern]

How much boost are you guys running on your sled with arp headstuds and no headshim . Also how much octane fuel are you running . This is on an rx1 with stock Pistons and rods still . I am getting the headshim taken out and at the same time getting arp headstuds installed . This way I get more compression for better throttle response . Just seeing what boost levels people are running . Thanks

 

[Yamadog]

Just my .02 cents but there are different ways to get throttle response without removing the safety of the shim. Who's turbo and is it a rear mount in the RX. There are quicker spool waste gates that can help and it is much cheaper than opening up the motor. If it is rear mount there is always going to be delay. I am running 3 hole Viper with MPI turbo and when built it had their stock waste gate, low compression pistons and arp studs. When I changed to the quick spool gate there is no lag but it is front mount turbo.

 

[rx1 fern]

I have a front mount powderlites kit. With 2860 turbo . What wastegate you using . I have a vortech one which is good also . My sled is coming apart for a gasket change so that is why I'm thinking of taking the headshim off . It spools good now but more compression is a lot better . I will use race fuel too. This is an rx1 also by the way . Shim is good for running more boost on pump gas like I do now .just looking for some thoughts . Thank you

 

[Yamadog]

I have the quick spool from MPI and yes if you plan to run higher octane you will be fine. Some guys want to run 10 #'s of boost on 87 and the burn rate is just too fast for a stock compression motor and stock timing. Especially on a motor that turns 11,000 rpms. Increasing the compression leads to pre-detonation from lower octane. I only had 1 rx with a Bender rear mount on it and it was horrible the lag was centuries and the jetting was a nightmare. When it was running I was at 10 #'s with a shim so not sure where you can go on that one but my 15 viper is being built with stock everything and will handle 9#'s with race gas, 6#'s on 91. My 14 has low compression pistons (half way between stock and head shim) arp studs and carrillo rods and will be at 20#'s of boost on all race gas.

 

[rx1 fern]

thanks yamadog .how much boost do you think i can run with the arp studs and stock gasket with vp q116 race fuel.i know i will have a lot more compression now without the headshim so i probably don't have to run that much boost .my old setup with the headshim i was running 20 pounds boost .this is still a stock engine .thanks for the help .gonna use sled for just racing now so it will be ran on race fuel .

 

[rx1 fern]

i am also getting my msd mc4 ignition installed ,this will give me the stutter to build boost off the line .

 

[Yamadog]

Boy its just a guess but I would think that lowering the boost 5 lbs with the race fuel should be OK especially if your doinn 660 1000 wot Burns

 

[rx1 fern]

thanks yamadog ,but what do you think if i run 20 pounds boost still without headshim with q116 fuel .do you think its too much boost .thanks for the input

 

[Yamadog]

Boy Rx I would not want to give that kind of advice. There has got to be some one out here that has more experience with those 4 holers maybe Ted Janetty.

 

[kinger]

Use the boost calculator in the sticky at the top of this forum. Its extremely accurate and will let you run all sorts of combinations and tell you the fuel you need. I set up my 91 octane 10-11 psi apex using it. If you can't figure out the spreadsheet then don't mess with the $5K motor LOL

 

[Wildman]

Your rods will exit the block before you have to worry about running out of octane on Q16. I've seen stock rods give out at 20# and seen them last at 28# for many races. Timing control becomes important with stock compression and high boost. I won't give a number as your starting to play with fire on a stock motor and arp studs are a waste of money with a stock bottom end. If your popping HG you have a poorly tuned machines and putting studs in will just make it find the next weakest link (your rods). Good Luck

 

[rx1 fern]

Thanks for the reply but I have been beating on this sled and racing it for 10 years with a front mount powderlites kit . Upgraded header and turbo and exhaust now though . So 10 years on sled with a shim on it I decided to not put it back on and go with stock gasket and arp headstuds . I also have a msd mc4 going on sled now . lakercr on here is doing the install .so to me the sled has been pretty good for years of racing it .

 

[Wildman]

Great, why not ask the guy that's changing the HG then lol. He should be able to tell you exactly what you need to hear as you seem to ask for opinions then when given one discard it. Good Luck, aren't you the one that dogged Hurricane for not giving you unending free help and everyone that tried to help you before. After 10 years of running your sled, you should know its capabilities.

 

[rx1 fern]

Settle down buddy . This post was asked way before I took sled to get the work done to it . I am just looking for other people's opinion .the sled is in very good hands as they were the ones that built it 10 years ago (lakercr). Their work is top notch and that is why I took it to them again .and as far as hurricane I no longer buy off him here in Canada . I order all my stuff from other people for my other sleds. His loss . So settle down as I'm just looking for people's opinions if they have done the same as I am doing now

 

[Yamadog]

We all need a bit of snow we are starting to get testicle!