Low vs High Compression Turbo Pistons

[merrell30]

I am hoping someone can offer some advice on a build I am doing. Street use but do go to the track. Will be 300+ hp.

I have a 2015 Hayabusa that has a intercooled turbo(garrett gt35r), 83 mm bore, forged Carillo rods, lightened and race balanced crank, oversized valves, port and polish. Web camshafts turbo grind .377/.366 lift and duration 270/261. Current piston choice is Wossner 9:1 low compression with no base spacer.

Is going with low compression pistons giving up a lot of HP and making the turbo work extra hard for no reason?

Would it be better to go with high compression pistons or am I headed for detonation and lower motor life? 13:1?

Thanks for any advice

 

[Dnyce]

keep what u got

 

[michael parris heuberger]

I am hoping someone can offer some advice on a build I am doing. Street use but do go to the track. Will be 300+ hp.

I have a 2015 Hayabusa that has a intercooled turbo(garrett gt35r), 83 mm bore, forged Carillo rods, lightened and race balanced crank, oversized valves, port and polish. Web camshafts turbo grind .377/.366 lift and duration 270/261. Current piston choice is Wossner 9:1 low compression with no base spacer.

Is going with low compression pistons giving up a lot of HP and making the turbo work extra hard for no reason?

Would it be better to go with high compression pistons or am I headed for detonation and lower motor life? 13:1?

Thanks for any advice

Hi. I have gone with Garrett G42-1200C and custom 10- to 1 JE pistons and Carillo custom rods as you want to use the 20mm piston pins not the 18mm ones that the Gen2 uses. Also you want a Gen one block Gen2 blocks tend to crack. What class and type of racing do you plan to do? I will be racing on the 1000 to 1350cc class in LSR racing. I will also use NOS to help spool that big turbo to make over 800 HP to 1000HP. If you want you can call me 508-496-3412

 

[busakiller]

You will be just fine. Your motor is a 1441 and has cams. Yes the low compression will hurt you but everything else will help you. I say leave it alone. I would get 10.1 pistons but I would go any higher then that. The more compression you run the less boost you can run on the same fuel. More boost is more power cause it’s more air you can force into the cylinder. More compression is less area to stuff the boost into. So at some point it’s pointless to go up in compression. I say build and have fun. If you don’t like it after a year or 2 then get some custom pistons and up the compression.

 

[busakiller]

I also heard of some new turbos out there with spool valves to help the turbo spool up faster but idk if the bike world has started using them yet.

 

[Bigboy Busa2]

More compression faster spool, lower compression slower spool but more boost. Find median with your build

 

[OB_THE MOTORHEAD]

More compression makes off boost more responsive and it also makes more hp so the time it takes to get to the rpm the turbo comes in is less.

 

[01smokes]

I've never ever felt turbo lag on my bikes. They have 6 gears and a clutch so lag is a moot point. I'm of the high boost high compression type of mentality. The fuels we have today are so great at keeping detonation away.

 

[202mphbusa]

I am hoping someone can offer some advice on a build I am doing. Street use but do go to the track. Will be 300+ hp.

I have a 2015 Hayabusa that has a intercooled turbo(garrett gt35r), 83 mm bore, forged Carillo rods, lightened and race balanced crank, oversized valves, port and polish. Web camshafts turbo grind .377/.366 lift and duration 270/261. Current piston choice is Wossner 9:1 low compression with no base spacer.

Is going with low compression pistons giving up a lot of HP and making the turbo work extra hard for no reason?

Would it be better to go with high compression pistons or am I headed for detonation and lower motor life? 13:1?

Thanks for any advice

Re reading your combo the two questions I have are
1 air to air or liquid intercooler?
2 Why don't you have 300 HP already? sounds like the combo you have is more than capable

 

[Rick D]

I agree you should get 300 easily. I make 300 with a gen1 stock crank, stock pistons and rods. I do have an 0.80 spacer though. I have no intercooler either. I did port my head myself though with stock cams. So for what you have 300 is very little HP.... So yes low compression is the best and safest way to go. Trust me the boost will more than make up for it.