needadvice

If I'm correct you can just hone the LSX iron block and you would have a 4.00bore, then just use a 4.00 stroke and I'd have a 402ci. RIGHT?????

That with a single turbo, FI-98X will be the turbo. OFI kit.

402ci + FI-98X + 6 bolt heads (probably ETP) + sheet metal intake

Main question: Is that the best bore/stroke combo?

full time race gas
weekend car only
street car/show car

DrTurbo

iTrader: (3)

That will be a handful!!!! A FI-98X is a 7 second turbo.......crazy weekend car...lol

Shawn @ VA Speed

iTrader: (3)

if your going to go that far,i would reccomend run a 4.125 bore and 4'' stroke,the bigger heads will flow better on the big bore,basically free hp.

veee8

iTrader: (40)

Agreed, that is when most bigger valve heads really start to shine.

Phil99vette

iTrader: (11)

4.185 x 4" here. With the right head gasket combo the setup will live at high HP levels. We've made about 1700hp at the tires and no signs of problems.

needadvice

so a 440ci with the ETP LS7 rectangular port heads?

Thats not too many cubes?

needadvice

is the 440ci the one that made 1700 RWHP?

Shawn @ VA Speed

iTrader: (3)

it's actually 438,but yes it's made 1700 so far,has alot more left in it,we havent even started pushing it yet,should be well above 2000

needadvice

I guess the question is: the chart with the FI-98X says its good to 1,975 hp. How does one build a motor to max out the potential of a turbo..or get damn close to it?

And before you ask, heck YES, 1,700 RWHP would be plenty. My goal is 1,500RWHP using an FI-98X on a ?????? cubic inch motor.

DrTurbo

iTrader: (3)

You have to match the compressor map and turbine map to an engine. Alot of even the professional racers don't do this and end up with backpressure problems or hot outlet temps. I can plot it all out for you if you need it.

needadvice

Yeah, I'd like to do it right the first time out. I'm certainly not expecting and really have no use for 1,975 HP, but I'd like to build a nicely matched set-up.

If you could plot it out I'd appreciate it, I'd like to see it. Then I could consult with my builder.

Thanks.

DrTurbo

iTrader: (3)

Ok....doing the #'s, you need ~161 lbs/min, PR 2.84 would be needed on a 402 revving to 7K rpms. This means you need a turbine flow of about ~75lbs/min. The FI98-X would be in the 70% eff range...which is good. Turbine side would need the larger A/R to reach turbine flow.

Mr.MartyStone

iTrader: (12)

What is spool on that 98X compared to your typical thumper 98mm?

Nate

DrTurbo

iTrader: (3)

About 600-1000rpms sooner depending on engine size. The larger the engine the less difference....but its still a good bit. Same as a GT55-91 vs a T91.5 thumper.

Phil99vette

iTrader: (11)

I mis-quoted you. My Bore is 4.175, my head gasket is 4.185, so its a 438". yes its the one that made ~1700rwhp on medium boost level. We're expecting another 600-700rwhp out of the combo.

DrTurbo

iTrader: (3)

Are you sticking with the 106?

Phil99vette

iTrader: (11)

Yes unless we switch to twins. We think its got a 4.80 and a bottom 7 in it.

DrTurbo

iTrader: (3)

Yeah with a 106 you should be able to. That first 100ft is the key for sure....

ls1290

iTrader: (20)

Most people shoot for that range as the final numbers That will be awesome if you can pull those extra ponies out of the combo Phil.

Keith

Phil99vette

iTrader: (11)

Keith,
I think we can. Looking at the data no the run and from what a couple in "the know" have said we have an easy 500rwhp on the table.

Drturbo,
We've been a 1.301 60' on the small tires. On the big tires we've inched the 60' down .03 each pass by adding alittle to the 2 step RPM. Each time we add it picks up .03 EXACTLY to the number.