Will my Gn-1's do the job.....

[Trbobuick]

Was going to go stock block, low tens. Now going S2 271 cube .

Heads are 14 bolt ported by tom at champion.

Heads flow a max of 261 @ 600 lift.

Will these heads flow enough for a 9.50-9.60 pass at 28 psi?

76 turbo, 96 lbs inj, 3400 lbs, ect

I do not plan on going faster than mid nines.
( I have some alum S2 heads and intake for that )


TIA
Brian

 

[GNSCOTT]

Yea, Jack Cotton ran a 9.7 with that combo before he went w/ the 80

 

[HighPSI]

IMO, You have a lot better chance getting that ET, than you will getting 28psi out of it. The two 274 motors I have seen with that turbo were only able to generate around 25psi max. With a custom ram air, you might get 28.

 

[S2V6RACER]

Who flowed the heads?

 

[Trbobuick]

Champion.....and they are friggen HUGE ports.

Sleeve pressed in , big valves, ect.


with an intake to match.

 

[TurboDiverArt]

Originally posted by HighPSI
IMO, You have a lot better chance getting that ET, than you will getting 28psi out of it. The two 274 motors I have seen with that turbo were only able to generate around 25psi max. With a custom ram air, you might get 28.

I'd agree with Cal. I don't have the Dyno sheets in front of me but from the Dyno numbers that Duttweiler did when building my motor, there is only marginal gain between 25 psi and 29 psi. You're probably better off for the longevity of the motor to run between 23 and 25 psi.

 

[Trbobuick]

SECOND QUESTION-

How much hp am i giving up over the gn1-r's?

20-30? 70?


Thanks

 

[TurboTR]

With those flow numbers, none that I can see. FWIW that's more than my R's flowed, also ported by Champion.

TurboTR

 

[Chuck Leeper]

How old?

If those are not the latest R series heads and are of the 14 bolt design, I doubt you'll have much luck w/ getting past the first dyno pull at the boost you are looking for, before they crack. BTDT

 

[Trbobuick]

i bought these brand new from champion in june. they are the senond gen 14 bolt NON r heads.


im going to have to call tom...4th guy now that says my 1.90 valve heads out flow the r's.

 

[VictoryTrans]

My dad went 9.59 with non-R heads and a 74 turbo w/ 26psi

 

[NJTurbo]

I would think that you would want to run in the 23-25 psi area, IMO 28psi is pushing the envolope and like some other people stated some people lost hp at higher boost levels. I know i am building my engine to run 23-25 tops. If i want to push to go faster i will look into better 60foot times and some weight reduction. I would hate to blow headgaskets on a 15k engine because i was maxing out on the boost side. 28psi is alot IMO. I think Jack runs around 23-25 and have seen him in the mid nines. Again just my 2 cents. With the flow numbers you have you should be fine providing fuel, timing, spool and all the other goodies are there.

 

[opeltwinturbo]

With the flow numbers you have you should be fine providing fuel, timing, spool and all the other goodies are there.

28-30# of boost will work fine on a good set of S2 heads using the Felpro 1007 gasket. However, once you get over 30# you loose all recordability on the FAST program using a 3 bar MAP sensor.

Unfortunately, when I switched from twin 63's to 68's, my stock HKS waste gates wouldn't handle the flow and I was overboosting. I was able to make several throttle controlled passes at 33#. I did make the last pass of the year on full throttle @ 37# but blew the head gasket crossing the finish line. MPH was 6-7 mph (179.73) greater that it should have been. While running the 63's, I had boost control and no head gasket problems @ 29#.

John Schmidt