Head shim?

playboy2k4 · Post by **playboy2k4** » Wed Mar 22, 2006 11:38 pm

Hey , does anyone know where to get a head shim from? and is anybody running them on their car right now if so , how good does it work? I'll appreciate any help I can get on this.

minnimert · Post by **minnimert** » Thu Mar 23, 2006 7:26 am

TypeRT on the other .org sells them. Go Here

hul kogan · Post by **hul kogan** » Wed Mar 29, 2006 3:38 pm

^ that is a really nice piece, btw.

Chris

quicksilvr · Post by **quicksilvr** » Wed Mar 29, 2006 4:53 pm

Agreed. TypeRT's shim is really nice, and very well priced. My brother bought one, and it's waiting with the other pile of parts until everything else has been got.

unsuper man · Post by **unsuper man** » Thu Mar 30, 2006 7:04 pm

tell me this.

head shim. lowers compression, thus letting you run MORE boost. so lets make a fake equation to help illastait.

a 2003 dodge neon with stock 9.3:1 compression makes 225whp @ 9psi of boost.

now we take said car, install a head shim, there by lowering compression to almost 8.3:1.

now that same car redynos at 9psi, big surprise, it makes less then 225whp. so lets up the boost, say 5psi, and wala, we back to 225whp.

now, what have we accomplished, well for starters, we spent 150$s on a fnacy head gasket so our boost guage could rear a few more psi, weve made are already slow car, even MORE laggy since the drop im compression will push back the full spool rpm. and now we have to worry about RETURNING with the high boost.

tell me what the point is? id really like to know...because the shim dosnt make the stock rods stronger, or make the stock pistons handle more TQ. so tell me, can we make more power with a shim? or can we just make power differently?

i fail to see the point is making the car respond worse at the cost of running more boost.

someone care to inlighten me?

unsuper man · Post by **unsuper man** » Fri Mar 31, 2006 11:48 am

anyone?

minnimert · Post by **minnimert** » Fri Mar 31, 2006 12:35 pm

The "Theroy" is, low comp high boost > high comp less boost.
Now is that how it works in real life? Beats me, I've never tested it. I never even read any actual dyno test in mags about it either.
I've seen engines built both ways that are equally as fast.

Is it worth the hassle of a tear down and loss of off boost power? I personally don't think so, but he only asked were to buy, them so I told him.

weber · Post by **weber** » Fri Mar 31, 2006 2:48 pm

lower compression leaves you with a larger tuning window. makes it easier to 'safely' tune your car without having AS large of a threat of detonation.

higher compression needs less boost, but you better damn well tune it right the first time

quicksilvr · Post by **quicksilvr** » Fri Mar 31, 2006 5:54 pm

weber wrote:lower compression leaves you with a larger tuning window. makes it easier to 'safely' tune your car without having AS large of a threat of detonation.

higher compression needs less boost, but you better damn well tune it right the first time

^ exactly. Using the shim would almost be too much of a hassle to mess with if a person wasn't planning on taking the head off in the first place. But in any situation where the head IS coming off, a nice head shim like TypeRT's (only $75) is a worthwhile investment in my opinion, simply for safety's sake. And, refering to unsuperman's example, if you have an older engine with 9.8 compression (my case), opposed to 9.3, the shim makes even more sense. I do agree though, you have to pay attention to the whole setup and not do something totally dumb like run 8.3 compression on an atx with a huge cam. That makes me cringe thinking about how bad it would feel at 2500 rpm.

Kevin_GP · Post by **Kevin_GP** » Fri Mar 31, 2006 8:38 pm

Ehh, i have 9.8 compression and my tuning window is large enough to work with. I agree with quicksilvr, the only reason i would use one would be if i was taking the head off. And if i was tearing into the head I might as well build the bottem end while im at it. I dont see the point in them either. Your limited by your rods, so with a stock bottem end you have to run low psi anyway.

playboy2k4 · Post by **playboy2k4** » Tue Apr 04, 2006 1:25 pm

Yeah I decided not to do it because a friend said the same thing that if I was to pull the head off to put a shim on I might as well just build the bottem end. Makes more sense that instead of running just PSI run BARS. haha

kArLoZ · Post by **kArLoZ** » Tue Mar 13, 2007 2:27 pm

Can I use headshim with stock internals??? how many psi can I get??? and WHP???

grindpunk16 · Post by **grindpunk16** » Tue Mar 13, 2007 2:59 pm

depending on the turbo a headshim can work nicely allowing you to run more boost make big power but keeping that killer torque number down. i mean omniphil made 27xwhp and like 23x-24xwtq with a headshim and a 50trim, on stock block. but depending on what turbo you have is the key. tuning window isnt all of it. spool of the turbo what you are using to tune. all of that comes into fact. an srt turbo will make huge amounts of torque regardless.

kArLoZ · Post by **kArLoZ** » Tue Mar 13, 2007 3:40 pm

my turbo is a MITSU from a 2.5T, I have neo SAFC to tune this

or I don't need head shim??

esteinmaier · Post by **esteinmaier** » Tue Mar 13, 2007 7:03 pm

Are you competent enough at tuning the car to keep it from detonating at about 7-12psi depending on the turbo? If so, then a head shim is both a waste of money, and a drain on performance.
With internals strong enough to handle more power, I could see a compression drop making more sense, however, why use a head shim, when you can just buy lower compression pistons?

kArLoZ · Post by **kArLoZ** » Tue Mar 13, 2007 11:36 pm

maybe 1 year, maybe 6 month, but now, i'm not going to buy them
If i'm not good enought to tuning the car, will it better that i bouth the shim??

Ryanm07 · Post by **Ryanm07** » Wed Mar 14, 2007 12:29 am

as already stated, larger tuning window.

lower compression=less detonation.

its just safer on a turbo car.

I've had one sitting in my closet for several months now, now that its warm out maybe i'll put it on. has anyone had any problems with leaking head gaskets often? i'm at 150k last 10-15k with the turbo and i've still had no problems with the head gasket, i'd like to keep it that way if i put the shim on.

BlackRoseRacing · Post by **BlackRoseRacing** » Wed Mar 14, 2007 5:32 am

I could see a compression drop making more sense, however, why use a head shim, when you can just buy lower compression pistons?

Its a cheap way out Vs replacing the bottom end....

Here's some quick info for ya:

Re: head spacers vs. low compression pistons (::R18) » « » 2:39 AM 3-6-2007

Quote, originally posted by ::R18 »
what are they for head spacers vs. low compression pistons for lower compression on a FI engine?

By design, head shims (sometimes called head savers, such as by FelPro) are designed to be used when your cylinder head has been milled to the point that your static compression ratio is bumped over the threshold of detonation. Ideally, installing the shim under your shaved head will restore you to your OEM compression ratio, more or less, and will prevent you from having to buy a new head (or a whole new engine if the detonation gets out of control).

Forced induction tends to be less tempermental when accompanied by lower static compression. It isn't that you can't boost a high compression engine, but said engine will need some fairly "exotic" tuning (at least for the average backyard mechanic) and will also need lots of octane to stave off deadly detonation. If you're on a budget--or if you must get by with pump premium rather than jet fuel, or if you're no Mister Wizard of chip tuning--then you can typically make power more reliably by running low compression + high boost rather than high compression + low boost.

Having said that, installing head shims instead of lower compression pistons isn't the smartest way to go. For starters, new slugs can drop you a full point of compression (or more, if that's what you want/need) and that's more than most shims (typically only .020" thick) can do for you. Adding a shim may let you increase your boost by a few psi, for example, and if that's all you want then maybe you're okay. But if you're thinking a shim is the magic ticket to running 25 psi on your 10.0:1 engine... well, you may be in for disappointment.

Furthermore, new pistons can still maintain proper quench characteristics, which will help combat detonation. Thick shims tend to ruin your quench, which in turn increases your chances of detonation... and isn't that what we were trying to prevent in the first place?

You also have to take into consideration of a few other things. Like for instance the amount of power you want to achieve, and the strength of the platform you are dealing with. Since we are talking about VR6's here, for instance the VR will handle 18psi dead on all day long with proper tuning. There is no reason to install forged pistons and rods for that application, it's just a waste of money. Maybe some rod bolts for the hell of it and call it a day.
It's all about the outcome you want from the motor and the application it's being used for. There's more to engine building then just slapping some rods and pistons with some standard static compression to make big power.

^^^
Info borrowed from:
http://forums.vwvortex.com/zerothread?id=3111356
Easier to copy and paste Vs me typing it all out

00element10 · Post by **00element10** » Wed Mar 14, 2007 2:33 pm

what would happen if you ran both, lower comp pistons and a head shim,

esteinmaier · Post by **esteinmaier** » Wed Mar 14, 2007 5:59 pm

The car would feel very very slow until boost hit.

kArLoZ · Post by **kArLoZ** » Wed Mar 14, 2007 11:15 pm

i don't what to much lag, thats why I choose a small turbo, i'm thinkin about using a headshim with my mitsu @ 15-17psi
will it good enought?

Ryanm07 · Post by **Ryanm07** » Wed Mar 14, 2007 11:26 pm

blackroseracing- those quotes were a good find.

and after reading that just incase noone knows typeRT's head shims lower your compression ratio a full point, and are made for a forced induction application, not to save a head thats been shaved too much.

60trim · Post by **60trim** » Thu Mar 15, 2007 1:06 am

esteinmaier wrote:The car would feel very very slow until boost hit.

basically...go get into a civic with a gt-37r...and hold on

00element10 · Post by **00element10** » Thu Mar 15, 2007 8:37 am

well i've chosen the gt35R to replace my crappy 16g, i have a head shim on the motor that's in the car, wasnt sure if it would be wise to reuse it. There's also going to be a 100 shot of n2o for this new motor as well. Should I use the shim or no?

Kevin_GP · Post by **Kevin_GP** » Thu Mar 15, 2007 8:57 am

Dude a head shim is a cheap way to lower the compression, its a band-aid fix. Its just a cheap way to open up your tuning window a little bit, thats all. If you want to run a big turbo, or a turbo+ nitrous then you need built internals, simple as that. When you build your block, you are adding low compression pistons, the right way to lower compression. Lowering your compression is not adding power, its taking power away. You don't want to lower your compression a huge amount for no reason. Head shims are only for people on stock blocks that want a little larger tuning window, which not every one agrees is completely necessary.

00element10 · Post by **00element10** » Thu Mar 15, 2007 11:42 am

even so, it was just a question because it'll be a drag car, and most likely a drag car only, so i'm going to be running a lot of psi and n2o on top of that so i figured id ask. if i cant use the shim, whatever, i'll sell it for a couple bucks.

and karloz, you're never going to be able to run 15-17psi with the headshim on stock internals...i couldnt even run 10psi for more than a week.

Thunderstruck · Post by **Thunderstruck** » Thu Mar 15, 2007 12:19 pm

Years ago I owned an 89 Plymouth Voyager (minvan) with a turbo motor. Yep a factory turbo minivan.

The factory compression ratio was fairly low and so was the boost. The van was a slug till boost hit then it was ok. Now branted we're talking avehicle that far outweights a Neon and at 5 psi or so of factory boost is probably substantially less boosted than you guys are thinking of running but the fact still remains that off boost with a low compression 4 cylinder torque was pathetic. I don't care what you boost numbers are, off boost numbers will be substantially less.

Now there are ways to remiediate it. If it's a stick keep the revs up and stay on boost. If it's an automagic then change the upshift governor to make it upshift at higher rpm and adjust the kickdown so that it kicks down sooner. That'll keep the boost up.

I ended up restting the boost level so that I got 12 psi and that woke the thing up. later I replaced the mitsu turbo with an earlier garret and it made 25+ psi. Of course I wasn't setup to run 25+ psi, I forgot to hook up the wastegate line. One instance of detonation and my number 4 rod bearing was flattened to the thickness of a piece of paper and the number 4 rod was eggshaped on the big end. This was on my test drive immediately after the swap. Funny thing is I had an intercooler set to go in and an alcohol injection setup too. That was the next mod, but it wasn;t to be.

Steve

BlackRoseRacing · Post by **BlackRoseRacing** » Fri Mar 16, 2007 6:49 am

^^^
I bet it was great while it lasted

My old T2 daytona with a fresh motor overspooled and it was unbelievable until I blew a hole right through the piston

Thunderstruck · Post by **Thunderstruck** » Fri Mar 16, 2007 12:28 pm

Yep, when it was setup with the Mitsu turbo and 12 psi it was fun. I used to work 2nd shift and by the time I got home I was passing the local strip just as everyone came home. Lots of big winged fart cannoneers got spanked by the van. Didn't hurt that it had the typical peeling paint and shopping cart rash. I also had a gutted cat and a high flow muffler. But it was quiet, except for the turbo whine it'd pass for a 150k mile beater visually and audibly.

Steve