[ethrjock]

Maybe I should have started with this:

The next goal for my stang is to put the car in the mid to low 10s but doing it with a solid internal foundation that if I had the itch, could build the top end (and all the other supporting mods to the rear) to get into the 9's. Looking for opinions on rotating assemblies to support that.

I from the camp...do it right the first time, build a solid foundation with options to grow with your "investment" says the guy running 12lbs of boost on a stock block

[HBK_2007]

Originally Posted by NastyStang113 Just something to add to the conversation... If you're going to be running a 'normal' amount of boost like 8-13 lbs than there is ZERO issue with running a stock or slightly higher compression ratio. I believe our stock motors are 9.8:1. If you're planning on running a lot of boost than it's probably not a bad idea to get the lower compression pistons.

u think 10:1 c/r, 10 psi, and 91 octane would be a safe combo at 7200ft elevation?

[DiMora]

Stock compression is 9.8:1

Livernois offers 9.1:1 and 9.7:1 on their stroker setups.

Roush's P-51 forged "R2300 short block" setup (stock bore diameter and NOT a stroker) offers Mahle pistons with a 16cc dish resulting in compression of 8.6:1.

Basically, it works like this based on what I know, have read, and the tuners I've spoken with:

A high compression engine run with pump gas is more likely to have detonation as more boost is added. To compensate for this, the tuner has to decrease (pull) timing.

Decreasing the compression ratio (via the use of lower-compression pistons) allows more boost to be run with more timing.

The engine-build and past tuning experience at various speed-shops has shown them that lower compression ratio pistons allow them to get the most power...ie turn up the boost as high as they can without detonation on the best pump gas they can get - which is going to be 91,92, 0r 93 depending on where you live, and may contain 10% ethanol in it.

So what is better? Take the same blower at the same boost with the same gas, but put it on two engines that are identical (except for the CR) and then start playing with timing...which one is going to make more power?

Remember, we are keeping boost constant in my example. The low CR engine is going to make LESS power at the same timing as the high CR engine. But as we add timing to the low CR engine, its power output could surpass the high CR engine. The high CR engine would not be able to make as much power, since we could not add more timing SAFELY.

But when you are making your final setup, timing is not the only variable...you actually adjust multiple variables...obviously A/F ratio, but also pulley size (for boost) as well as timing and more.

The low CR engine is going to allow you to run more boost with more timing, and based on the knowledge and experience of the tuners I've worked with (both car and motorcycle) the engine with the lower CR in a boosted application is going to make MORE power SAFELY vs. the high CR engine...and that makes sense when you look at the offerings that specialized tuners such as Roush and Livernois build - those places ALWAYS offer lower CR pistons for boosted applications.

My opinion...

I'd say if you KNOW you are going to want to go faster and faster...plan on low CR pistons for sure...and if you are going to pull blocks and do a swap, my opinion is why not do a stroker. As a wise old-timer once told me (and this holds true even when boosted)..."There is no replacement for displacement!"

[DiMora]

Also, this is a good read to help you understand all this boost vs. timing vs. CR stuff...and he throws octane into the mix as well:

Tech Page

[DiMora]

Originally Posted by HBK_2007 u think 10:1 c/r, 10 psi, and 91 octane would be a safe combo at 7200ft elevation?

My opinion - should be safe

...stock compression is 9.8:1

You are talking about the slightest increase in CR...and lots of guys are running 10-12 PSI on stock compression (like me) with success. The difference is your timing will probably be around 15-17 degrees (My current tune is at 17 degrees)...whereas with low CR pistons you might use more timing (and therefore make more power safely).

If you are going to pull the engine, why not do it all at once and do it decisively to plan for the future so you are not held back by your block / rotating assembly: Forged low CR stroker FTW!

[HBK_2007]

Originally Posted by DiMora My opinion - should be safe ...stock compression is 9.8:1 You are talking about the slightest increase in CR...and lots of guys are running 10-12 PSI on stock compression (like me) with success. The difference is your timing will probably be around 15-17 degrees (My current tune is at 17 degrees)...whereas with low CR pistons you might use more timing (and therefore make more power safely). If you are going to pull the engine, why not do it all at once and do it decisively to plan for the future so you are not held back by your block / rotating assembly: Forged low CR stroker FTW!

my boost adder will be a turbo and ive been told turbos like a little higher CR than superchargers

[DiMora]

Originally Posted by HBK_2007 my boost adder will be a turbo and ive been told turbos like a little higher CR than superchargers

Boost is boost when it comes to CR.

Turbos require less total crank HP to make an equivalent RWHP, but as far as A/F ratio, timing, detonation, fuel octane, etc. that is all the same on turbo vs. supercharger.

With that said, the merit in that argument is the fact that turbos, like Centris, need to "spool up", and therefore when running one of those many guys prefer a higher CR (and therefore lower total boost and total HP) in order to get more grunt "off the line".

[05roush0090]

Saleen Rotating Assembly Upgrade 4.6L to 5.0L Supercharger - Blocks, Heads, & Intakes - Automotive

Is this the same kit?

[usafimj]

Thats the company I bought my kit from but from ebay and $400 cheaper. But like I said I sold it due to having military overseas orders

[05roush0090]

Man $400 cheaper would be one hell of a deal.

[jonnieguns]

Does the 8-bolt crank fit stock S197 flywheels?

[JakeM]

Originally Posted by jonnieguns Does the 8-bolt crank fit stock S197 flywheels?

Nope.

[HBK_2007]

Originally Posted by Towelly Nope.

i was gonna say that i thought all forged mod cranks where 8bolt and 3v's dont have stock forged cranks

[mod06saleen]

I have the kit "s/c 302" and I bought it from ebay, probably the same seller. He sells a lot of these parts. I have an 06 saleen s281. I want to be in the 750-800 hp range. I am looking at the kenne bell 2.8 mamoth. Is the kit in question going to support the power? I have been told the pistons may need to be changed out. Any advise on other parts? I know fuel, susp, drivetrain, ect. but i need specific info. Like "this kit works or says it will" type of info. I am stationed here in gtmo and need help finding parts that I will need to complete the build when I get home.

[usafimj]

I believe you should be fine with that kit. Its the same kit that gets put into the Saleen 302 Extremes that puts out 620hp/600tq from the factory. For the fuel system look into the GT500 fuel kit and it you need KB BAP and 60 or 80# injectors will be needed. Suspension is all up to you and how much you want to spend. Drivetrain will need to be upgraded to a 6spd or have the 5spd beefed up. You might need to upgrade your heads and cams. You might need a new block if your stock block can't work with the pistons in the kit

Use the search function and look up what your going to need. Lots of info out there and good luck

[mod06saleen]

your military? stationed?'

[usafimj]

USAF, Tinker AFB, Oklahoma

[mod06saleen]

I am in cuba

[mod06saleen]

I am looking at the tr-6060 from d&d. they sell a swap kit. Wondering if that is worth it cause may change shifter and drive shaft out and you still have to buy flywheel and clutch. Would it be better to put the kit together myself from differant vendors? I have been looking at the fore kit at lethal perf. its costly (2k) but I don't think I will out grow it. They say it will support over a 1000 hp but I will still have to buy injectors. Another couple of hundred bucks. This is the parts list: The Lethal Performance Complete Fuel System Includes:
-Fore Precision Works Triple Pump Fuel Hat
-3 Ford GT Supercar Pumps
-Zone 5 Performance MDM Mega Driver Module
-Fore Precision Works High Flow Fuel Rails -Satin or Black
-Aeromotive 10 or 100 Micron Fuel Filter
-Fragola 3000 Series Pushlite Fuel Hose
-Fore Precision High Flow Y Block -OEM Level Sender -Fragola Fittings, Clamps, and all Hardware needed for installation
-Complete Installation Instructions
Any way to get these parts cheeeeper? Just looking to save some where I can this is going to be an expensive build. Any I deas?