I have eagle standard length rods, je 8.8:1 pistons, and all the rest of the goodies to make a nicely powerful daily driver.

question: If I install this HG shim in between my MLS head gasket, acting as an agent to lower my compression further, is that a bad idea? It will be lowered to approximately 8:1.

HG shim: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=009&item=190040718089&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

another post (many successes using this shim):http://forums.neons.org/viewtopic.php?p=1503176

1. will it effect my gas mileage?
2. will there me a noticably considerable amount of power loss in the lower rpm band range?
3. Any other things I may should be aware of before I do this?

I do plan on running lot o' boost, but I want to open up my "tuning window" with this lower compression. I want to see how much boost I can run on 93 octane without knock.

anyone ever done this before? How much boost is possible without knock at 93 octane?

(of course all of this will be done on the dyno, with ignition retard)(msd dis-2)

if you have such a huge intercooler, ignition control, and dyno time... why do you need to lower the comp more then 8.8:1? 7.8:1 is way low IMO.

YES you will loose some torque,
YES your milage will drop some,
Yes, I would be concerned with it sealing... you are atleast going to use ARP hardware right?

I would suggest keeping things at 8.8:1CR for now. It sounds like you've got a good set up going, there. Fill 'er up with the 93 and start tuning. I can't say what you're going to get out of her on that CR with the 93, but see what you get first.

I'd also venture to say this isn't the sort of thing I would look to buy on eBay.

EDIT:
Got any more information about your turbo (model and trim) and fuel system? You've got the DIS for ignition; how are you tuning the fuel?

Who gives a shit how much boost you run? I'd rather make 400whp on 15psi than 30psi...

that thing is a cheap deck plate and I would never, ever reccommend it. One...leaks. how many headgaskets do you need with this fucker, 2? those headgaskets take up space as well. two, its made out of cheap 304SS.

any machine shop can make you something better. better as in, since you have a taller deck height, use longer rods and stock pistons. offset ground crank, etc etc. take advantage of the space there.

thats my take on it.

also, dropping the compression 1 full point is definately not a great way to increase efficiency. Unless you put more energy into it with more boost and fuel, its just hurting you across the whole rpm range. especially low end, which youre going to need against the brutes out there.

i drove a 2.4 with stock 8:1 CR pistons and no turbo and my gosh, was it slow. turbo makes a big difference, but the higher compression AND the turbo put it into a whole other category. its like driving your car in the rain everyday.

Yeah Mikey, I told you that that was too low, but if you just want to run 30lbs of boost, go for it. I can't wait until you get through with it though. You NEED to just give me one of your bottom ends though :) j/k. But seriously I am getting ready to drop some dough. Just be ready for me.

Originally posted by turbo8u
how many headgaskets do you need with this fucker, 2? those headgaskets take up space as well. two, its made out of cheap 304SS. any machine shop can make you something better. better as in, since you have a taller deck height, use longer rods and stock pistons. offset ground crank, etc etc. take advantage of the space there. thats my take on it. also, dropping the compression 1 full point is definately not a great way to increase efficiency. Unless you put more energy into it with more boost and fuel, its just hurting you across the whole rpm range. especially low end, which youre going to need against the brutes out there. i drove a 2.4 with stock 8:1 CR pistons and no turbo and my gosh, was it slow. turbo makes a big difference, but the higher compression AND the turbo put it into a whole other category. its like driving your car in the rain everyday.

use only one HG, (see above post by me)

I'm not gonna buy longer rods, use what i got.

i will be putting more energy on it.

lower compression + turbo = bigger tuning window (which is what i'll need at 25+lbs boost.

Originally posted by Chamuko
if you have such a huge intercooler, ignition control, and dyno time... why do you need to lower the comp more then 8.8:1? 7.8:1 is way low IMO. YES you will loose some torque, YES your milage will drop some, Yes, I would be concerned with it sealing... you are atleast going to use ARP hardware right?

the plate replaces the middle layer of the 3 layer MLS HG. It should be coated with a copper HG sealant. I've talked to many of users that have this and they've never had leaks.

this was not only sold on ebay...

yes, i'll be using ARP goodies.
yes, i'll be doing 25+ boost, or at least as much as 93 octane'll support...

i'll never race from a roll either

So it sounds like you've already made up your mind you're going to use it. Why the hell are you asking us?

Originally posted by DarkOne
So it sounds like you've already made up your mind you're going to use it. Why the hell are you asking us?

seriously.

ive run 21 psi with my s16g on 91 octane, it rips hard as shit and it has no detonation. you don't need your little happy plate if you know what youre doing.

Originally posted by DarkOne
So it sounds like you've already made up your mind you're going to use it. Why the hell are you asking us?

oh humble dark one... all i'm asking is opinions/suggestions

this plate makes me happpyy, lol, i just want to make sure i'm not jumping into something that i'll have a problem with later on down the road as i've never done this before. i haven't made up my mind darky.

the main reason for me posting this is to see if anyone's ever tried this, what high boost people are doing best, and what to avoid when doing this.

All i've done is read on doing this, thats why i've posted. figured i'd get some professional/intelligent feedback

all im saying is I have personally felt 8:1 compression on a LARGER motor and it sucked bad. I hated it. even with the turbo it didnt feel as lively as it should have. When the compression came up, I was scared of my throttle then. Think about what youre doing with a turbo anyway, you're effectively raising the compression ratio. At 1 BAR of boost, with 8:1 compression, your compression ratio is exactly double. Directly affects power output.

you say in your FIRST SENTENCE you want a DAILY DRIVER

so don't buy this little shim crap then.

Thats my advice.

did he just call Dino humble?

wow, thats some good ish your smoking lol.

Well, info has been passed along to you, still sounds like your leaning twoards it. Go for it, be the test subject...report back.

Um I run 25psi without that piece of shit with no problem...

Originally posted by eclipse982nrRST
Um I run 25psi without that piece of shit with no problem...

at what octane..? do u have knock? whats ur fuel management/timing...

Originally posted by eclipse982nrRST
Um I run 25psi without that piece of shit with no problem...

You guys soooo don't understand. This shim was made to provide some insurance to those people who did not want to rebuild their stock bottom end. Tuners have been using shims for years without any problems. However, the reason you would use these with a built bottom end is if you head the block or head decked.

Most companies, Like HKS, that mass produce these shims use aluminum or copper. BECAUSE they are CHEAPER THAT 304SS.

So while I would love to stay and dispute this with you. The proof is in the history.

Now, when you are ready to move up to another car because you are tired of this one or when you grenade your engine and you can't get your money back out of your built bottom end, you will understand the relevance of a device like this.

$65 dollars is a good price for cheap insurance. and you don't even have to mess with the engine to get it back to stock.

both my 90 Talon TSI And Chrysler Conquest have a compression ratio lower that 8:1 so yeah, the factory was crazy 7:8.1 is way too low.

In hindsight, the the engineers at Mitsubishi should have googled to find a good forum with vast knowledge of turbocharging and gotten some advice from the layman.

Originally posted by daytonturbo

Originally posted by eclipse982nrRST Um I run 25psi without that piece of shit with no problem...

um, eclipse982nrRST - time for a bigger turbo - there are N/A Neons running your times without a turbo. You guys are SOOOOOOO lost.

Good for them, props to them.

And um, you must have missed the thread where I bought and used a GT35r turbo for about a week and didnt like it.

You seem like you know EVERYTHING and dont have time for us weeklings so post your timeslips pussy lips.

lollll, well there's a nice intelligent answer, thank you friend.

Originally posted by daytonturbo

Originally posted by eclipse982nrRST Um I run 25psi without that piece of shit with no problem...

You guys soooo don't understand. This shim was made to provide some insurance to those people who did not want to rebuild their stock bottom end. Tuners have been using shims for years without any problems. However, the reason you would use these with a built bottom end is if you head the block or head decked. Most companies, Like HKS, that mass produce these shims use aluminum or copper. BECAUSE they are CHEAPER THAT 304SS. So while I would love to stay and dispute this with you. The proof is in the history. Now, when you are ready to move up to another car because you are tired of this one or when you grenade your engine and you can't get your money back out of your built bottom end, you will understand the relevance of a device like this. $65 dollars is a good price for cheap insurance. and you don't even have to mess with the engine to get it back to stock. both my 90 Talon TSI And Chrysler Conquest have a compression ratio lower that 8:1 so yeah, the factory was crazy 7:8.1 is way too low. In hindsight, the the engineers at Mitsubishi should have googled to find a good forum with vast knowledge of turbocharging and gotten some advice from the layman.

I understand perfectly fine. I think you might be missing some important infor yourself...Do you know the strencgth of those materials? or how they could seal better? That our heads are aluminum?

Ths truth is, this guy has a BUILT block. Not a stock one. He asked about HIS set up, not a stock one. This is on a MODERN engine (Im sure the mitsu engineres saw the light and wanted to keep the comp ratio in the 7's but those damn bean counters wanted a higer comp...

Originally posted by Chamuko

Originally posted by daytonturbo

Originally posted by eclipse982nrRST Um I run 25psi without that piece of shit with no problem...

You guys soooo don't understand. This shim was made to provide some insurance to those people who did not want to rebuild their stock bottom end. Tuners have been using shims for years without any problems. However, the reason you would use these with a built bottom end is if you head the block or head decked. Most companies, Like HKS, that mass produce these shims use aluminum or copper. BECAUSE they are CHEAPER THAT 304SS. So while I would love to stay and dispute this with you. The proof is in the history. Now, when you are ready to move up to another car because you are tired of this one or when you grenade your engine and you can't get your money back out of your built bottom end, you will understand the relevance of a device like this. $65 dollars is a good price for cheap insurance. and you don't even have to mess with the engine to get it back to stock. both my 90 Talon TSI And Chrysler Conquest have a compression ratio lower that 8:1 so yeah, the factory was crazy 7:8.1 is way too low. In hindsight, the the engineers at Mitsubishi should have googled to find a good forum with vast knowledge of turbocharging and gotten some advice from the layman.

I understand perfectly fine. I think you might be missing some important infor yourself...Do you know the strencgth of those materials? or how they could seal better? That our heads are aluminum? Ths truth is, this guy has a BUILT block. Not a stock one. He asked about HIS set up, not a stock one. This is on a MODERN engine (Im sure the mitsu engineres saw the light and wanted to keep the comp ratio in the 7's but those damn bean counters wanted a higer comp...

Thank you. You said it a lot nicer than I planned.

Go fix your neon now.

I understand perfectly fine. I think you might be missing some important infor yourself...Do you know the strencgth of those materials? or how they could seal better? That our heads are aluminum? Ths truth is, this guy has a BUILT block. Not a stock one. He asked about HIS set up, not a stock one. This is on a MODERN engine (Im sure the mitsu engineres saw the light and wanted to keep the comp ratio in the 7's but those damn bean counters wanted a higer comp...


So OK, I came off a little harsh. You guys should have at least gotten with me before you started bashing. I don't post much here but I have been on the forums for a few years.


Strength of what materials? 304ss? yes, it is very strong. regardless of the material the shim is very thin and could probably be made of steel for this purpose. I have never had one fail.

how what could seal better? the shim? Mopar recomends using head gasket sealer or copper gasket sealer anyway. The shims will not seal without having at least one layer of the MLS gasket on each side. Cometic and many other manufacturers do the same thing.

Most stock MLS headgaskets are made from a rubber coated spring steel. I have never blown a MLS headgasket.

yes, a built block, I know that now. This shim was never meant for the purpose of running it on, or making better, a built block. It was meant as a very cheap alternative to building your block.

Obviously, it does not make the internals any stronger. What it does is lower combustion chamber temps. Heat is your piston killer wether hyper, cast, or forged.

I have seen first hand in my Neon what detonation does to a Hyper piston. I melted one myself running just 8psi on my first turbo kit. Which I pieced together my self in 2000 without much outside help. Guess what, IT was too hot in the cumbustion chamber due to lack of fuel. So I used some of the technology that HKS used on the Supra and made a shim. This shim is just cheap insurance and allows for mistakes such as melted pistons that most people can't afford.

Originally posted by daytonturbo
Obviously, it does not make the internals any stronger. What it does is lower combustion chamber temps. Heat is your piston killer wether hyper, cast, or forged. I have seen first hand in my Neon what detonation does to a Hyper piston. I melted one myself running just 8psi on my first turbo kit. Which I pieced together my self in 2000 without much outside help. Guess what, IT was too hot in the cumbustion chamber due to lack of fuel. So I used some of the technology that HKS used on the Supra and made a shim. This shim is just cheap insurance and allows for mistakes such as melted pistons that most people can't afford.

This man speaks the truth, though if you want to get technical, shims still reduce the available quench area by spacing te head further away, which can, even on some modern motors, make them more prone to detonation. 8.8:1 JE pistons are deigned to mimic the same quench area as a stock piston with lowered compression. If you want less than 8.8:1 compression, don't shim it - use the right piston. JE will make them for barely more than you'd pay for a shelf set.

i'm glad this post was made. Should help some people down the road.

Originally posted by DarkOne

Originally posted by daytonturbo Obviously, it does not make the internals any stronger. What it does is lower combustion chamber temps. Heat is your piston killer wether hyper, cast, or forged. I have seen first hand in my Neon what detonation does to a Hyper piston. I melted one myself running just 8psi on my first turbo kit. Which I pieced together my self in 2000 without much outside help. Guess what, IT was too hot in the cumbustion chamber due to lack of fuel. So I used some of the technology that HKS used on the Supra and made a shim. This shim is just cheap insurance and allows for mistakes such as melted pistons that most people can't afford.

This man speaks the truth, though if you want to get technical, shims still reduce the available quench area by spacing te head further away, which can, even on some modern motors, make them more prone to detonation. 8.8:1 JE pistons are deigned to mimic the same quench area as a stock piston with lowered compression. If you want less than 8.8:1 compression, don't shim it - use the right piston. JE will make them for barely more than you'd pay for a shelf set.

yup JE kicks ass, I have a buddy from school that just graduated and is working for em...Hopefully they will taking new ppls ina year or so.

I wasnt talking about the SS, I was talking about the other materials. As far as a HKS, again, not what I was talking about.

I give you props for your idea, If I came off as bashing, then I apologise. Like Dino said, theres more to it then just increasing the deck height.

This is an interesting thread. Drama aside, there is some good tech being discussed. Word to your mothers for keeping it civil.

daytona-dude - Thanks for coming out of the wood work and posting. It's good to see people who have learned from this site by reading, passing their knowledge and experience back by posting.

Personally, the only time I think I might be tempted by this sort of thing would be if I was looking to run more than 7lbs on a stock bottom end with an HRC/Star kit. Even then, I wonder if the drop in CR would negate the gains from three additional pounds of boost at that level of tune. :shrug

The weak link would still be there IMO. it only takes one serious incident of knock to take it all away. Now if you want to feel safer about the max recommended levels... thats another thing. Then IT WOULD be extra inssurance, not just a half assed attempt to push more boost, If you have the head off, whynot take the damn oil pan our and put in new pistons?

thats my 2 cents...

Originally posted by Chamuko
If you have the head off, whynot take the damn oil pan our and put in new pistons? thats my 2 cents...

loll, thats what i'm scream'n :)

does lower compression necessarily mean "more insurance" under 20+ psi boosted applications??

is 8:1 better for 20+psi boost than 8.8:1?