Dr. D-Series

Id like to know #'s.
Or just how bad you think it was, if bad at all.

Reason is I just picked up a low mileage Z1 block.
And I want to put it in as is.
With my head combo the comp will be about 7.7:1.

Thank you.

Personal experience would be great, a guessing game isnt what Im looking for.

b16sedan

I ran my B16 at 7.8:1 compression for a while, it didn't feel too bad off boost. Lots of people on here are going to tell you how shitty it'll feel off boost, but 99% of the people on here probably have not driven a low compression honda off of boost. If you feel it's driving like crap on the street, put in a thinner headgasket or mill your head, or both.

Dr. D-Series

I dont care how it feels off boost.
As long as on boost, Ill still get a nice kick in my pants.

What turbo were you using ? And ever dyno it ?

Thanks for the reply.

RyanEJ8

Uh oh.......here comes the Compression ****.

Dr. D-Series

Ryan im with you man, I love compression in every setup.

But I just spent 100 bucks on this clean block, and I wanna put it to use.

Ya know !

093turbo16

iTrader: (2)

Use it and just throw some boost at it.

RyanEJ8

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr. D-Series &raquo;</TD></TR><TR><TD CLASS="quote">Ryan im with you man, I love compression in every setup.

But I just spent 100 bucks on this clean block, and I wanna put it to use.

Ya know !</TD></TR></TABLE>

LOL, I was referring to b16coupe, him and I have had some arguments about what C/R to run with turbo.

Dr. D-Series

Well kiss and make up.

Im the center of attention now. Haha

Rofl

racinskittle

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe &raquo;</TD></TR><TR><TD CLASS="quote">I ran my B16 at 7.8:1 compression for a while, it didn't feel too bad off boost. Lots of people on here are going to tell you how shitty it'll feel off boost, but 99% of the people on here probably have not driven a low compression honda off of boost. If you feel it's driving like crap on the street, put in a thinner headgasket or mill your head, or both.</TD></TR></TABLE>

exactly. There's a certain value which is ideal yada yada yada, but when it comes down to it, it's not life or death

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr. D-Series &raquo;</TD></TR><TR><TD CLASS="quote">Well kiss and make up.

Im the center of attention now. Haha

Rofl</TD></TR></TABLE>

lol!

Dr. D-Series

Keep it coming !

Thanks for the bump skittle.

b16sedan

I was running an SC61E turbo on an inline pro log mani, spool up compared to stock 10.2:1 compression was exactly the same. My motor is in an EF sedan, and it pulled a bit on a friends EG making 410 WHP.

I prefer a lower compression motor for the street, especially if you're running a D-series motor, because I would gladly sacrifice a pinch of low end power so that I can run a few more pounds of boost on pump gas and get some more top end power out of it.

Dr. D-Series

Thanks for the input.

Boltz

bumping or lowered the compression a point or two shouldnt make a noticable difference in spool time.

If all you are worried about is in-boost performance, I say go for it.


Just remember, D series transmissions are gayer than south beach and that you should consider a decently spooling turbo if your running a z6/y8 trans

Dr. D-Series

**** it, ill do it.
I had my b7 block all cleaned and painted.
I guess its gonna be a big paper weight in my room now.

Ive got a z6 trans, and the snail is a ***** 42/48. Will spool up fine.

Thanks.

racinskittle

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr. D-Series &raquo;</TD></TR><TR><TD CLASS="quote">**** it, ill do it.
I had my b7 block all cleaned and painted.
I guess its gonna be a big paper weight in my room now.

Ive got a z6 trans, and the snail is a ***** 42/48. Will spool up fine.

Thanks.</TD></TR></TABLE>

Yeah that turbo will spool up REALLY quick. A good upgrade is the 60 trim T3 (.60/.48). There's a large noticable difference between the two. Spool up is still quick.

Dr. D-Series

I had a 60/63 on my last 10:1 setup.
But it was blowing oil like it was going out of style.

So I still have the 60 compressor housing and wheel and will upgrade sometime in the future.

racinskittle

yeah mine blows oil like crazy too haha

Dr. D-Series

You challenging me ?
My 60/63 was so bad, I could pour almost a 1/4 quart of oil out of my charge pipes.

Im not lying !

Haha

liam821

Evans tuning had a 10:1 vs 9:1 dyno comparision. Lost ~14hp. I had an old sohc with like 8.7:1 and i hated it. Zero power on the low end. Im much happier with my 9.4:1. Sohc needs all and any power you can get with no boost help.

http://www.evans-tuning.com/viewtopic.php?t=1612

liam

_entropy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by liam821 &raquo;</TD></TR><TR><TD CLASS="quote">
Evans tuning had a 10:1 vs 9:1 dyno comparision. Lost ~14hp. I had an old sohc with like 8.7:1 and i hated it. Zero power on the low end. Im much happier with my 9.4:1. Sohc needs all and any power you can get with no boost help.

http://www.evans-tuning.com/viewtopic.php?t=1612

liam</TD></TR></TABLE>

How the hell can you say that after seeing that graph? The difference off boost is like 3-5 WHP, and that's a full point drop in compression with a motor that started off with more N/A horsepower. A drop in compression in a motor making less horsepower will have a proportionately smaller drop in power. If you think your 9.4:1 setup feels so much better than your 8.7:1 setup, 95% of it is all in your head.

Dr. D-Series

I agree.

BTW I pulled the head off.
The block is ******* mint.
Cross hatch is so visible you can see it 20 feet away.
Its a "JDM D15b". But its a Vtec-E so basically a vx. P07 stamped everywhere.

Cant wait to put in a almost NEW motor.

IMPORT JEDI

i ran a vx bottom end with a a6 head.it wasnt bad but i was running 15-20 psi
on a t25. it was fun ran 12.98 at 105 on street tires in my ef hatch.lasted about 14,000 miles not bad for a throw away motor.

liam821

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by @lbert &raquo;</TD></TR><TR><TD CLASS="quote">

How the hell can you say that after seeing that graph? The difference off boost is like 3-5 WHP, and that's a full point drop in compression with a motor that started off with more N/A horsepower. A drop in compression in a motor making less horsepower will have a proportionately smaller drop in power. If you think your 9.4:1 setup feels so much better than your 8.7:1 setup, 95% of it is all in your head.</TD></TR></TABLE>

Your right - off boost power isnt much different. I was talking about on boost power however. Which still isnt that much.

Even if it was 5hp, your talking 5% power loss with a sohc.

However trust me, my old lower compression motor was a dog without the help of a turbo.

liam

RyanEJ8

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by liam821 &raquo;</TD></TR><TR><TD CLASS="quote">

Your right - off boost power isnt much different. I was talking about on boost power however. Which still isnt that much.

Even if it was 5hp, your talking 5% power loss with a sohc.

However trust me, my old lower compression motor was a dog without the help of a turbo.

liam</TD></TR></TABLE>

Considering out of boost hp on a SOHC is probably between 40 and 70whp, not 100whp, 5whp is alot more than 5%. It's more like 7-12% loss in power, which is alot. If you put a good CAI, header, and exhaust on an N/A SOHC you probably won't even gain 12%.

Everyone simply thinks "What does a 5hp loss out of boost matter on a turbo car making 300whp+, it's just 5hp?" Well, 5 hp is alot when you're only making 70whp at your current rpm/load. This is why anyone that thinks 1 point of compression drop will have minimal affects on acceleration, throttle response, and spool up is just plain wrong.

_entropy

Compression doesn't have any effect on spool. Reading that thread on Jeff Evan's board shows spool up is identical between 9:1 and 10:1

My point is a full point drop in compression isn't going to cost you 5 WHP be it a D-series or a B18 or an H22, losses in power from a decrease in static compression will be a percentage and linear based on how much power your engine currently makes. So 5 WHP off boost might be 3% on a motor making 150 WHP originally, so start off witha motor making 90 WHP and you might lose 3 WHP. I own a high comp turbo car, I have friends that own low comp turbo cars, and they're so similar that I just don't think you can say that 7 tenths of a point in compression changes your car from feeling like a dog to feeling awesome on the low end.