17cc or 10cc Piston

[cobra29]

What's the difference between a 17cc and 10cc pistons. Pros and Cons. I have some extra $$$ and I want to do a rebuild in the coming winter.

 

[Quadcammer]

kind of a vague question.

simple answer, 7cc. the 10cc piston will have like 9.1 compression compared to 8.5 for the 17cc. depends on what your setup is and the goals you have for your vehicle.

 

[KGblack99cobra]

Yea like Quad said... ( In love with those numbers "DROOLING" )
Whats your projected Plan .... N/a or P/a

I put in 17cc dished on mine, lowered compression to 8.5.1 and now shes a pig... Just saving for blower to Change that... I get to run more boost thanks to the 17cc's but yea know... I need the car back for the 3rd time

 

[NXSVTCOBRA]

if i were gonna do a boosted street car, i'd go with less dish, lets say a centri. blower with 9.5:1 compression you could push more or less the same boost, and have more power down low, in oppose to lower compression, and when its time to crank up the boost, do the same for the octane and you'll be pretty safe.....

 

[KGblack99cobra]

if i were gonna do a boosted street car, i'd go with less dish, lets say a centri. blower with 9.5:1 compression you could push more or less the same boost, and have more power down low, in oppose to lower compression, and when its time to crank up the boost, do the same for the octane and you'll be pretty safe.....

Well damn, i dont know Crap... LOL
Always learning via this board....

so 8.5.1 compression was a dumb move on my part?

 

[George Wax]

I have 8:79: to 1 final compression ratio. I have a Vortech E-trim blower. Car does feel like it has no low end. However, when on boost car has plenty of power. Plus I am in California where the gas octane is 91, so I figured my engine should live a little longer with less compression. On the upside if I ever decide to go turbo I have pretty much the right compression. If you do decide to go with higher compression your tune better be right on the money or else you will detonate to hell.......This is the way I look at it.. More compression no room for error. Low compression more room for error with your tune..

 

[Quadcammer]

Well damn, i dont know Crap... LOL
Always learning via this board....

so 8.5.1 compression was a dumb move on my part?

No.
more compression will make more power, but you will be closing the gap on the tuning window (less margin for error). With 8.5 cr you can run more boost on pump gas, and the tune can be a little more aggressive. You will lose some torque and the car will be slightly sluggish out of boost, but when you need the power the boost is there.

I wouldn't do it any other way for a pure street car.

 

[cobra29]

Well, I am leanning towards a turbo setup. And I want to go with CP Pistons. Now the question is what cc? I want to squese(sp) every ozs of juice out of this thing. I'll be happy if I get in the 600 hp range. I only drive my car about twice a month. I want it to be somewhat streetable but mostly drag. Lets say 40%street and 60% drag strip.

 

[hatsharpener]

I'd lean towards the 17cc pistons (8.5:1 compression) for a turbo setup.

 

[KGblack99cobra]

No.
more compression will make more power, but you will be closing the gap on the tuning window (less margin for error). With 8.5 cr you can run more boost on pump gas, and the tune can be a little more aggressive. You will lose some torque and the car will be slightly sluggish out of boost, but when you need the power the boost is there.

I wouldn't do it any other way for a pure street car.

Well im rebuilding the motor and im going to go with JE Flat Top pistons..i about 10.1 maybe 11.1 compression and then maybe spray or boost.
would it be safe to boost with high compression?

 

[cobraracer46]

Well im rebuilding the motor and im going to go with JE Flat Top pistons..i about 10.1 maybe 11.1 compression and then maybe spray or boost.
would it be safe to boost with high compression?

Griggs Racing has a 98 Cobra convertible with ported 01 heads, 01 intake and 11 to one compression pistons teamed up with a Vortech SQ blower pullied for 10 pounds of boost and it puts down more than 660 RWHP and on top of that, the car serves as daily transportation. If I decide to go with forced induction on my cobra, I will also go with a high compression short block. I think lowering compresion on a centrifical blower combination run on the street would be a mistake since the comprssion loss would make the car feel guttless down low.

 

[Quadcammer]

if you want to run on the ragged edge all the time, then sure, run 11:1 compression. I be t the griggs car runs on race gas.

boohoo, the compression loss makes it feel gutless down low. Guess what, all cobras are gutless down low. Its a tiny motor with no balls below 3k. dropping compression a bit isn't gonna change that. Thats why you gear it properly and if you want power, you downshift.

you want lowend torque? go buy an 03 cobra or ls1.

 

[KGblack99cobra]

i just want to know that im build a good setup... I know i will never be the fastest car around, but i just do not want to build a motor and end up being no faster then i was stock..
Thats my only concern...
From my reading on the board, i have formed my own theory that high compression is a good application for N/A and then Lowered compression not low compression is a smart choice for boosted cars.. and as for wanting torque down low, buy a kenne bell or roots style blower am i right. Our motor are high rev motors so centrif produce great numbers up high where a majority of us do our driving/racing at.
Gearing it right, I choose 3.90s and i believe when i get to drive it, with a strong running motor, ill be more then happy, compared to the stock motor with stock 3.27 gears am i right..

 

[Quadcammer]

you can't build a blower motor, then drive it without the blower and be pissed. it just doesn't work like that. for huge power up top, you give up some down low.

if you only want like 500rwhp or so, then stick with 9.5 or stock compression. But if you really want to push the limits, while retaining some safety, then id stay with lower compression.

 

[KGblack99cobra]

Thanks bro.. Youve taught me a Sh*t Load...
I know that i can expect blower power with no blower...
I was just saying.. i have the option right now to either build a low compression motor or a high compression motor... Which one would you do?

 

[cobra29]

Where can I buy some CP pistons?

 

[Quadcammer]

Thanks bro.. Youve taught me a Sh*t Load...
I know that i can expect blower power with no blower...
I was just saying.. i have the option right now to either build a low compression motor or a high compression motor... Which one would you do?

what are your end goals, and when do you think you will be getting the blower? would you monetarily and practically be able to freshen the motor up with new pistons?

i need to know more about the situation.


cobra 29, either propower or modularperformance.com.

oh or VT engines.

 

[KGblack99cobra]

Ok, this is my current plan..
I am buying a 99 4v motor tonight, and taking the car to a new shop for the install,
It is a cast iron block and a 6 bolt cast crank. It has 99 Cobra pistons stock bore, new bearings, rings, rod bolts, main bolts and head bolts Rebuilt by Mike Nichalos in Waco (Upstanding Guy who stands behind his work and will use it only till I finish my built motor)

My starting point for the built motor is as follows:
Alum block bored .20 over,
forged rods/pistons/arp 2000 studs& Forged crank (scrapping these)
I plan on replacing everything with this kit :
KELLOGG Forged 4340 Steel Crankshaft
BRAND NEW MANLEY 4340 H-Beam Rods
MAHLE Forged Dished Pistons 16cc 3.572" bore
(Fully CNC Machined, Tool Steel Pins, Wirelocks for full floating, 16cc radiused dish, 3.572 -.020" over bore)
MAHLE Plasma Moly File to Fit Rings
(New low drag racing ring "1.5mm, 1.5mm, 3mm" design)

How does that sound, what else would you recommend...End Goals are roughly 500hp and reliable, She will not be my daily like she was..
So i want a nice respectable, Street car, more then a stock 99.

 

[SPICER]

hey Mike Nichalos lives down the street from my house. He has a pretty bad ass gt that he races

 

[cobraracer46]

if you want to run on the ragged edge all the time, then sure, run 11:1 compression. I be t the griggs car runs on race gas.

boohoo, the compression loss makes it feel gutless down low. Guess what, all cobras are gutless down low. Its a tiny motor with no balls below 3k. dropping compression a bit isn't gonna change that. Thats why you gear it properly and if you want power, you downshift.

you want lowend torque? go buy an 03 cobra or ls1.

I spoke with owner of the Griggs convertible and he did not mention using race gas on the daily driven Cobra. Griggs has proven that you don't need give up low end tourque with a centrifical blower. Even Sean Hyland says one should not drop commpresion when running centrifical blowers because the car looses too much low end that cannot be regaind by the blower. Why set up a street driven vehicle to feel like a pig in the rpm range where it is driven most? Makes no sense to me. Keep the compression high and a cobra will have good low end torque.