Turbo pistons and turbo heads?

[Justin_sane]

I posted this question in the polaris turbo section but i have not gotten much action there (could be because I asked it in my build thread), so I figured I would post it here.

I have some Wiseco turbo pistons on the way for my Assault, (part number SK1393). They are listed as 8.5:1 compression (seems pretty low for a sled motor, but I bought them anyways).

I also wanted to pick up a set of power addiction racing turbo heads as found in the following link;
POLARIS CFI 800 HEAD, Power Addiction Racing

I was wondering which head I should run with. I emailed PAR and havent gotten a response for almost a week. I was thinking that the turbo heads might lower the compression too much, giving a poor idle or whatever. It should allow higher boost, but im not sure just how much boost a sled motor can take without problems anyways.

anyone have any recommendations for the head selection? I was thinking I should almost run with the lowest compression NA head...?


EDIT forgot the details: I will be running 100LL avgas, looking for 10-12 psi, running Air to water IC, I have the Ekey as a backup as well, looking for 250+ hp

 

[Holden_magroin]

I definitely wouldn't go that low, I have a 12 assault and am running a silber turbo and a boondocker e key with AvGas and can do 8 pounds at low elevation so I'm guessing I should be able to do 12 up top, I was going to do the lowest compression pa head but everyone talked me out of it due to the low bottom end I would get from running super low compression and av gas. Those pistons seem extremely low compression since the turbo head from pa is 12:1 or something. I plan on using the pa turbo head with my e key and when I do a top end I'll put the same compression pistons in. And apparently you can't run last 15 psi on a pro with out a bigger fuel pump. Oh and I had good luck with calling pa, good guys to deal with hope that helps

 

[Justin_sane]

Well once the pistons showed up it all made sense. Wisecos catalog is messed. They listed the pistons as 795cc iq dragon turbo. Turns out the are 750cc four stroke turbo. Ive sent them back and they are replacig them with iq dragon standard size. So i will go with the low compression turbo heads from par.

Should be a fun ride.hopefully they get here soon so i can ride itwith turbo before christmas

 

[St0rm77]

hey there Justin, how'd you make out with the pistons and head? i'll be running pretty much the same setup as far as the turbo goes, and was hoping you had some starting numbers for the control box...:d

 

[cat925]

I posted this question in the polaris turbo section but i have not gotten much action there (could be because I asked it in my build thread), so I figured I would post it here.

I have some Wiseco turbo pistons on the way for my Assault, (part number SK1393). They are listed as 8.5:1 compression (seems pretty low for a sled motor, but I bought them anyways).

I also wanted to pick up a set of power addiction racing turbo heads as found in the following link;
POLARIS CFI 800 HEAD, Power Addiction Racing

I was wondering which head I should run with. I emailed PAR and havent gotten a response for almost a week. I was thinking that the turbo heads might lower the compression too much, giving a poor idle or whatever. It should allow higher boost, but im not sure just how much boost a sled motor can take without problems anyways.

anyone have any recommendations for the head selection? I was thinking I should almost run with the lowest compression NA head...?


EDIT forgot the details: I will be running 100LL avgas, looking for 10-12 psi, running Air to water IC, I have the Ekey as a backup as well, looking for 250+ hp

If you want to run that much boost you will need at least 111 to be safe

 

[Justin_sane]

well, I was about to get everything going and had a pile of problems (in the polaris section youll see the details). i will likely be running the fix kit (mtntk) and i have par 11.0 heads. I will be just requesting that wiseco refunds my money (rather thjan exchanging the pistons). I will let you know when its running. should be getting it going again this week, so i will post some more details as i go (here and in my build thread). I may get out to Blue River this coming weekend to test it, if not im planning to go to sicamous in feb, so I should be able to have some results soon. Im planning to run AvGas, so i will see what I can get out of it for boost on that. I have the Ekey, so I can definetly run more boost, but at the expense of timing, so ill have to investigate as to what puts out higher power. I definetly dont want to run 111, because i can buy literally twice as much fuel for the same price if i run av gas. I am also planning to run my turbo MR2 on an AvGas tune as well.