9.5 aluminator vs 11to1

[stretchb]

This is different than a blower with a fixed pulley. You have a boost controller keeping boost up for the lower compression piston to maintain the boost at 15.6 psi. So your turbo's are making up some of the difference for the lower compression piston.

im quite sure an aem tru-boost is not that smart.

ya that idea don't fly either because I ran my 1st pass stock motor street tune on just the w/g spring, trapped 134 which is the same on new motor. both passes being 10.30s

 

[Bud]

I do agree. I know my car 60ft is great, 330 time sux and my 1/8 is consistant 6.04-6.06 which sux. (the break a block pass was probably 22psi+ and the 1/8 was only 5.93 @123 et sucked)

the 1/4 trap speed have been 150 with both compressions though.....

And with the converter locked you'd think trap speed would be a good indicator, unless that is slipping too. And holy shit, I'd like to try 22psi! Just with somebody else's block.

When you logged was effective timing the same, it wasn't adding any on the 9.5 or taking any out on the 11 from the knock sensors?

 

[mebcop]

im quite sure an aem tru-boost is not that smart.

ya that idea don't fly either because I ran my 1st pass stock motor street tune on just the w/g spring, trapped 134 which is the same on new motor. both passes being 10.30s

the tru boost doesn't have to be "smart". That's exactly what it does, allows it to boost a specific level despite what has changed in the system.

 

[Doug1227]

That's not how it works. The turbo's wastegate WILL maintain the same boost regardless of temps, DA, etc., but this doesn't make it generate the same compression as a higher compression piston. There's a difference between combustion chamber pressures and boost pressures.

This is different than a blower with a fixed pulley. You have a boost controller keeping boost up for the lower compression piston to maintain the boost at 15.6 psi. So your turbo's are making up some of the difference for the lower compression piston.

 

[Shaun@AED]

same turbos.

the first built motor that broke that went 9.20s had the 67's on it. I have not had a tune change since before it blew up.

when I put the stock motor in to replace the blown one I put the smaller turbos on. I took the car to the track with same tune but started boost lower and went 9.58@148 11psi, 9.46@152 13.5psi, 9.37@154 15.6psi. state capitol raceway

went to track again and ran 2 more 9.37s at 150. 15.6psi with stocker. Baytown.

changed to aluminator went to track opening day Baytown 1/3/14 and left every the same made 2 passes went 9.37 at 150 boost still read 15.6psi

went to evadale 1/11/14 ran 9.40 at 150. boost still 15.6psi

all of these passes have been logged and I do have a 1/2 shift issue going on(on all passes) due to the converter being too loose.....we think

Ah, I have a hard time keeping up with all your changes!
Miss a week and I miss a different engine and turbo setup. LOL

 

[Shaun@AED]

FWIW we've done a few stock 11:1 to 9.5 Aluminator swaps with blower setups and lost 40+HP with the same pulley, stock heads/cams, etc.

 

[CPRsm]

That's not how it works. The turbo's wastegate WILL maintain the same boost regardless of temps, DA, etc., but this doesn't make it generate the same compression as a higher compression piston. There's a difference between combustion chamber pressures and boost pressures.

Nooooooo,almost though. A wastegate is purely mechanical. In theory it should maintain but it can fluctuate a bit. Not nearly what a blower will with the same changes though.

Compression bump will definetly cause more power and has been proven to do so many times. Not sure what variable is being missed here though. Maybe the converter is too loose for the higher CR? Like Bud said I'd be curious is a log shows more timing as well. But if the controller says 15.6 EXACTLY for every run, that would be the first place I'd look lol

I'd have to call and ask him again but last time I talked to Mihovetz he said a change of compression from 9 to 12-1 was worth over 200hp. That being the only change. He likes his compresion!!

 

[stretchb]

And with the converter locked you'd think trap speed would be a good indicator, unless that is slipping too. And holy shit, I'd like to try 22psi! Just with somebody else's block.

When you logged was effective timing the same, it wasn't adding any on the 9.5 or taking any out on the 11 from the knock sensors?

my built motor that tune was based on was so noisey from piston slap we had to turn knock off on the race tune.

 

[Bud]

I'm out of ideas, must be that on3 magic :shrug:

 

[CPRsm]

Well then WTF, idk either lol

 

[grnenvy]

There's a 4% power loss going from 11:1 to 9:5:1. That's 40-50 hp if your making 800hp. It's great your running the same but something has to be diff. U turbo guys can make that up with a small adjustment of the waste gate.
Nice car!

 

[scott9050]

1.41 60ft

Cool that Trace Adkins was there to watch you race.

;-)

 

[stretchb]

who's that ^^^ ?

 

[phil h]

So are the 60's staying on? Are those standadrd non billet wheel ones? I think i may pull the trigger on the kit this fall. Take my V3 kit off and sell it and put the on3 on.

 

[D.T.R]

Something doesn't add up here...

 

[Doug1227]

I'm guessing he's saying that the guy in the red jacket behind your car looks like the country singer Trace Adkins?

Cool that Trace Adkins was there to watch you race.

;-)

 

[Doug1227]

Wouldn't 4% be 33hp? 800/.96? I'm considering the 9.5, so you guys sort this out! Lol!

There's a 4% power loss going from 11:1 to 9:5:1. That's 40-50 hp if your making 800hp. It's great your running the same but something has to be diff. U turbo guys can make that up with a small adjustment of the waste gate.
Nice car!

 

[Shaun@AED]

Also take into account 1.5mm ring pack vs the stock 1.0mm.
Less friction from the stock setup.

 

[stretchb]

and valve springs ^^^ I guess.

 

[stretchb]

ya'll Mofo's need to quit hating on low compression ! lol