Asphalt Animal

Seems like most run low compression high boost. Can you help me understand why not very many people run high compression with low boost - is this not applying the same concept in a different manner?

Tony @ MPH

There's some stock compression Z06s (what is that -- 10.5:1?) running low to mid boost (5-9psi) with good results (500-600rwhp). I am actually surprised by the number of Z06s with 8+psi lately and no blown motors we've heard of. Just goes to show you how important the tune really is.

vetterdstr

9.6 to 1 compresion here w/10 lbs of boost. Off boost the car runs well and on boost its a wild animal. I understand LPE runs 8.6 to 1 compression on the 427 TT. Although the large CI motor prob makes up for lost power with such a low compression engine. I would hate to have a dog of a car off boost and have it be tempermental and peaky with wild power that is not linear to redline.

VR

baitbuster

I have the LPE 383 with 10:7:1 and I have ask them for the TT package. I'm taking the the car in late March to keep my compression high, they have agreed to do the job at six pounds of boost. If I feel that I need more I can lower the com. and add more boost. I'll let you know.

0Jeff @ TPE

Hey Brother,

I got your email, I just havent gotten a chance to reply.
If I were you I would go and talk to Rick over at Synergy. He is a GREAT guy and one of the most knowledgeable guys I have spoken to in regards to these cars. Plus he'll probably give you the slow car discount..

BTW, I should be taking a flight up to your neck of the woods in the next month or so. Maybe we can all go out and grab a btie to eat.

Jeff

Andy@A&ACorvette

You may remember at Christmas I gave Roy a blower on his 402.
It's 11:1 . I put on my S Trim blower and it's making about 6.5# of boost.
We were running it on the dyno today because he wanted alky injection installed.
The alky had a problem and was not working at all. It made 632 RWHP and 633 RWT. I expect to pick up more with the alky working properly.
The throttle response and low end torque is awsome with this combo.
Would we be able to make a bigger number with more boost and less compression? Definately. But I'll have to tell you. This car feels faster in everyday driving than the low compression, high boost cars.

DDSLT5

My car runs this compression ratio - it exhibits none of these traits. You're simply misinformed.

vetterdstr

What compression ratio is that? What boost level? Helps to have all this info on the table before telling me I am misinformed.

#001 2001 Z06

I should be able swing this in Feb..

Asphalt Animal?

Brent

DDSLT5

10-13 psi of boost on 8.5:1 CR. Motor feels as strong as stock in low rpms.

Asphalt Animal

Apparently we need some dyno charts from HIGH compression LOW boost cars. I can't imagine the power being non-linear but charts will talk and if the power is non-linear perhaps someone can explain why?

Andy what about that 11.0:1 you mentioned? Anyone else?

Asphalt Animal

Quote:

Originally Posted by diynoob

There's some stock compression Z06s (what is that -- 10.5:1?) running low to mid boost (5-9psi) with good results (500-600rwhp).

YES and they appear to have more low end torque (although less overall power) then their low compression counterparts - is this compression related?

Quote:

Originally Posted by leojnknsc5

High compression increases the need for high octane.

Wouldn't meth injection or torco balance this out with the same effects as low compression cars?

Quote:

Originally Posted by vetterdstr

I would hate to have a dog of a car off boost and have it be tempermental and peaky with wild power that is not linear to redline.

Wouldn't a higher compression car be less of a dog off boost and just as linear on boost? Help me understand this one.

Quote:

Originally Posted by baitbuster

I have the LPE 383 with 10:7:1 and I have ask them for the TT package. I'm taking the the car in late March to keep my compression high, they have agreed to do the job at six pounds of boost. If I feel that I need more I can lower the com. and add more boost. I'll let you know.

Please do! I'd really like to see this. Did they send you any dyno charts from similar cars they've done - if so please share.

Quote:

Originally Posted by american_hp

I got your email, I just havent gotten a chance to reply.

Jeff - I see your post, I just haven't gotten a chance to reply.

Quote:

Originally Posted by andy@AandAcorvette

You may remember at Christmas I gave Roy a blower on his 402. It's 11:1 . I put on my S Trim blower and it's making about 6.5# of boost.....It made 632 RWHP and 633 RWT.

That sounds incredible. What would you suggest and expect from a c5r 441 with 11:1 compression with 6-8#'s? Can you post a chart for Roy's car? (lucky bastard). I think I know what I want for Valentines Day.

bernrex

Good news here for those with the new 427 LS7 engine. I think its 11:1 compression also.

I'd bet someone is already adding some low 6-7 lbs boost to it ... could it be happening at your shop?

0Slowhawk

14lbs on the stock 10-1 compression here and no KR sensor's hooked up -15k miles so far

High compression works real good but you need to know what your driving and how to listen for problems.

We've tested compression on our race cars. A simple switch from 9.5-1 to 11-1 netted us 200rwhp with race fuel of course.
Superchargers respond to compression alot better than Turbo's.A recent 408/T88 Combo just pushed 820hp/780tw on our dyno then ran out of pump.We are adding a second pump and plan on pushing 900rwhp on 93 octain with this emmission legal 408ci. It's a simple compression/Cam selection

1%r

9.4.1 CR here @ 15 PSI and no issues on a little ECS 382 forged stroker.

vetterdstr

When I talked about low compression and motors and high boost I was thinking about cars with much lower compression that what we run and high boost in the 25 to 30 lb range.

So in closing, when I put up that last post, I wasnt talking about your application.

VR

0EG@EnglandGreen

Wow, Don!!

DDSLT5

9.6 to 1 compresion here w/10 lbs of boost. Off boost the car runs well and on boost its a wild animal. I understand LPE runs 8.6 to 1 compression on the 427 TT. Although the large CI motor prob makes up for lost power with such a low compression engine. I would hate to have a dog of a car off boost and have it be tempermental and peaky with wild power that is not linear to redline.

VR


Above is your exact quotation. You said the LPE 427 TT was a low compression engine and it would be a dog off boost with 8.6:1 compression ratio. Mine has less compression and less cubes. It is totally responsive at low rpms off boost. If you weren't intending to say what you said above, then you shouldn't have typed it!

R&D

You only lose about 3-4% hp for every full point static compression is dropped. So it's not like dropping a 10.5:1 compression engine down to 8.5:1 will totally kill off boost performance.

vetterdstr

Thnaks for your input... I am not going to try to explain my position again... but I will say its not as you perceived it.