Altering compression ratio?

[2_fast_240]

Ok, so ive been thinking about turbocharging or supercharging my KA here lately but it has 10.5:1 CR pistons in it right now. ive heard how different thickness head gaskets can change CR and that got me to thinkin. now im sure i cant get a head gasket thick enough to lower the CR to a boostable amount, but would it be possible to put a metal spacer type deal in there and just put a gasket on either side. Kind of like the opposite of head shaving. Someone tell me if there is a reason this idea might go terribly wrong or some factor im not considering because it seems like it would work fine to me.

[KA-T_240]

you could run boost on that compression ratio. I wouldnt want to do to much with out race fuel. would be intresting to see the numbers it would make.

A thicker head gasket wont changer your CR that much. It wouldn't probably get it under 10.0:1

[2_fast_240]

Dude, did you even read the post. i know a thicker head gasket wont change it much. Thats why im thinking about making some kind of metal spacer and putting a gasket on each side of the spacer.

[cdlong]

the spacer sounds like a bad idea. i doubt it would seal well. and with the amount of money involved you could probably buy another engine and swap it in and then sell yours at a profit. if i had an s13 and lived close to virginia, i'd be all over it.

not to mention the issues the thick head gasket would cause with cam timing and combustion chamber shape.

[wootwoot]

Suck it up and quit being a baby. People run boost on motors with higher compression then that. Super charge it mildly and be happy

[2_fast_240]

1)What would cause it to not seal well as long as the spacer was ground and perfectly flat/parallel.
2)This would cost me next to nothing since my dad owns a machine shop.
3)Exactly what issues would this cause with cam timing and combustion chamber shape, can someone elaborate on this. Because im not gonna attempt it if it will cause problems elsewhere.
4)What about this makes me a baby
5)If I were to supercharge it the way it is, would I be able to safely tune it with just a safc-2 and a lm-1

[Ninjabread]

the problem is that with that spacer, you would be changing your cam specs and shit. no good.

[wootwoot]

It will change the combustion chamber design and can make the squish area not as efficent. Can also mess with timing because of the new angles required and the extra length of belt. SCC did a thing on it not to long ago, look through some mags. They show the math so you can figure out if its bad or not

[johngriff]

Worked on an AUDI TT that utilized 6 cyl with head spacer plate for lowered compression, and turbos.

It worked: Horribly

Blown gaskets out the mother fucking ass.

PLUS, PLUS PLUS

A Custom timing chain will have to be fasioned because of the differnece in height.

You can run a turbo with this compression ratio, just need good gas, and VERY good timing. Very good timing.

I hear EMS system calling your name.

[2_fast_240]

To tell you the truth im a lot more interested in a supercharger than a turbo. If i were to run like 5 psi would I still need to get an EMS to adjust timing.

[bamaboy]

if you are just going 5 psi then don't worry about dropping you compression ratio....you should be fine if that's as high as you want to go.

[2_fast_240]

So your saying I will be fine running 5 psi and tuning it with just a safc-2 and lm-1. Or are you saying I will be fine as long as I get an EMS to tune it.

[johngriff]

NO SAFC, you must have timing control.

You will be fine as long as you have an ems to tune it. SAFC-II = Destroyed timing map on ECCS nissan.

[cdlong]

1)What would cause it to not seal well as long as the spacer was ground and perfectly flat/parallel.
2)This would cost me next to nothing since my dad owns a machine shop.
3)Exactly what issues would this cause with cam timing and combustion chamber shape, can someone elaborate on this. Because im not gonna attempt it if it will cause problems elsewhere.
4)What about this makes me a baby
5)If I were to supercharge it the way it is, would I be able to safely tune it with just a safc-2 and a lm-1

1)the answer to the first part of the question is in the second part of the question.
2)you would need new, possibly custom head bolts also. those would be fun to make
3)no expert on combustion chamber design, but as stated, it would reduce the quencing ability of the quench areas. i don't know how much that would harm the combustion process but in some engines it can kill any gains you hope to make in other areas. the SCC article referenced earlier was in the october '06 issue in the dear dave column. i can't find it on the website so head to your library, it's a good read. post up what you get on here, i'm curious now.
4)you are trying to half-ass something? i don't know, i didn't say it.
5)get a Bikirom, fuel and timing control and you can easily upgrade injectors, mafs, etc. and it's only like $450.

on a general note, 5 psi coming out of a non intercooled supercharger is a lot different than 5 psi out of a small turbo. some superchargers aren't too effecient and heat up the air a lot. no actual facts to offer you, just urguing you to research it some more.

[McRussellPants]

run sand through your motor untill your rings and pistons are so bad your actual compression is 8.0:1


that or the head spacer, either are equally ghetto.

[skatanic28]

if you can keep intake temps down and have timing control, that compression is probably alrite.

[johngriff]

Ask Neme(evan) about biki rom:keke:

[cdlong]

i've only heard good things about them, and i was about to buy one. searching through some of his posts it looks like he's haveing other issues with his car. for the price it's awesome, not everyone can afford a standalone.

[johngriff]

yeah but paying for mistakes is even worse!

[S14DB]

Standalone is cheaper than rebuilding the motor.

[cdlong]

what would blow the motor, the tuning, or the quality/design of the Biki?

if it's the tuning, that's the owner/user's fault.

if it's the design, what is it missing?

like i said, i've heard only good things about the biki, the quality can't be bad across the board.

[johngriff]

I am NOT a biki rom expert. NOT IN THE LEAST.

Evan was quite upset, and cant get his AFRs dialed in at all with it. He is going Haltech, once i make some majic happen for him.

You should really ask him the specifics.

[NemeGuero]

Biki is just hard to deal with. Tuning ISN'T real time so you're constantly making "guessing" changes and then re-uploading maps.

Sometimes the changes you make are beneficial, sometimes they aren't.
If you don't know ROM tuning or don't know someone who is willing to spend hours upon hours doing it for you $$$$$$$$, then don't get it.

BikiRom V3 (the latest software release) is terrible for self tuning. The display was much better in V1 and at least made it semi-doable for tuning.

I fixed the running issues with my car. It runs good now.. except my tune is still kinda rich, part throttle tune is all over the place, and I know I'm not extracting even close to all my engine's power potential.

You get what you pay for. And paying the hours to have someone tune your ROM for you equates buying a GOOD EMS and paying 3 hours to have it dialed in fuckin' PRO status.

I bet you've been waiting for me to say that, eh John? haha