head spacer??????

[Just4fun]

Might be the wrong forum but got an idea from a local racer that own's and races a 240sx. He has done incredible work on this car. But one thing that he pointed out is the head spacer that he had made :shock: I guess this lowers comp and allows for far greater boost. Now im no engineer but he kinda sold me on the idea. Said that you dont have to worry bout overboosting and blowing the head and or gasket. This car is scary fast, more so than i could imagine. Went for a ride and almost had to change my pants for good and bad reasons. Had perma grin for quite some time. Unfort though my quest now seems very slow. This car has spray, and some cryo unit for the intake, a huge turbo, and an intercooler that looks like it was pulled from some mack truck. How much of an advantage would this give if any?

[D_Venable]

the only thing that a spacer will do is give you another gasket to blow when you overboost it trying to make more power.

 

your only lowering the compression which equals less off bost power

[Richie_Rich]

Our cars are already only 7:1 stock.

 

Your friends car was probably over 9:1.

 

With the right fuel mixture, some guys are running in the 30's for boost.

How much more do you want?

 

You can lower your compression by doing some work in the chambers and shave the pistons down.

 

If you are into super boost, you should be using floating pins, so have the small end bushing bored offset to effectively shorten the rod.

[MontyTSI]

/ exactly..your friend did the "quick fix" for lowering compression. Our cars are factory turbo cars.

[EIGHTY8_TSI]

You can us a head spacer to lower your compression. Do your math so you know how thick to make it, make it out of steel and you wont ever blow it out just the sealer and thats a cheap fix. Lowering the comp means your just replacing it with boost just leave it and run a little less boost with a better head gasket.

[Technology]

Skyline people use head spacers to increase displacement too. You can add stroke to the crank and use longer rods for higher revving etc. There is a kit for skylines that changes the engine from 2.6 to 3 liters.

[Maxzillian]

Not too bad of an idea... just as long as your piston rings don't leave the block. :shock:

[MontyTSI]

you dont want lower compression than 7 to 1, your offboost performance will be terrible.

[Technology]

Not too bad of an idea... just as long as your piston rings don't leave the block. :shock:

 

I think if you did something like that, you'd use sleeve inserts or something like that. Infact, the more I think about this the more it sounds awesome. We could make the starquest a 3.2L 4cyl and rev to 8 w/out worrying too much. But if you're doing that much work to the block, you may as well find a DOHC head that has the same bore centers and adapt it to work with your block spacer.

 

Hot damn. This is my new "future project".

[Maxzillian]

Dunno, you could sleeve it and go for broke, but I think you'll soon run into issues with the timing chain.

[Technology]

Yeah, as soon as I posted, that was running through my head. But it kinda goes with that territory - if you're doing all that other work, a timing chain wouldn't be a problem. And if you stuck with the stock style head, you could just add links to the chain untill it fit.

[EIGHTY8_TSI]

"Theres no replacement for displacement" Im glad our cars are like big block 4 cylenders

[Hit_N_Run-player]

Skyline people use head spacers to increase displacement too. You can add stroke to the crank and use longer rods for higher revving etc. There is a kit for skylines that changes the engine from 2.6 to 3 liters.

 

this has been done to make a long rod SR20. A company called mazworx (SP?) is making 2.5L sr20's. there shop motor made over 1000whp IIRC.

[Indiana]

If you want more CCs you don't poke a piston out the top you just use a piston that doesn't have a long skirt and it just goes down further but this motor in carbureted form barely has 100hp if you lower a turbo CR you'll end up with a car a DelSlow will whip your arse before you get any boost and by the time you do get boost you'll be creating so much heat you just went backwards. Sounds like he is making up for not knowing how to control something or can't afford to buy what he needs to control something. CR multiplies with boost but additional boost psi means additional heat. He needs to start out CR as high as possible then know the limits of his motor THEN buy a turbo that fits what he has and most people when shopping for a turbo do it backwards and can't read a turbo compression map anyway or even know what one is. That same motor with the correct turbo and a higher starting CR and less boost could make more hp and run cooler and last longer. If you want a thicker gasket they already make thicker gaskets for this motor that had heads milled you don't need to make one a stock piston with that shim gasket is down in the mid to high 6:1 anyway (a POS SLOW DOG) who would want it you couldn't launch with it worth a damn it would bog down and practically die.

[Couth'nize]

.................and yet another useless mod idea for our engine......unless you got money, anything is possible.

 

 

Exit stage :arrow: .

[Technology]

Indiana, you should space out some of those ideas, it was punctuated, but still like a huge run-on sentence. Why are you talking about carbed engines? It comes fuel injected stock, and doing the right mods includes changing to MPI, not carbs. Carbs are for v8's.

 

All that stuff I said has been done on other cars. It works, but those cars also have dohc and other higher-tech stuff that makes it worth it.

 

As far as your argument about CR and boost and heat; you are reciting stuff we heard a long time ago and if you haven't been keeping up to date, there are lots of cool things like intercoolers that keep your intake temps pretty close to ambient. Top fuel cars have a static CR of like 4:1. they aren't doggy. they also run 150+ psi of boost, but you could run 50 psi in the quest and make 1200 hp.

[Indiana]

A carbureted 2.6 has flat top pistons with a CR of ~8.7:1 and has apx. 105hp

 

if you have a 6.5:1 CR and no boost what do you got?

 

where we at? I didn't know we jumped up to v8s with nos and 150psi

[Maxzillian]

I certainly agree that a low compression engine is going to be a real dog off boost. That being said, I can only see a lower than stock compression engine only being good for drag racing where you can pre-boost the engine.

 

For street and track cars where lag is an issue, compression is king.

 

In my case, I could only see using the head spacer as a means of allowing for more stroke without running exotic pistons or connecting rods. However, the block work required along with what must be done with the timing chain still doesn't make it a cheap solution.

[Technology]

A carbureted 2.6 has flat top pistons with a CR of ~8.7:1 and has apx. 105hp

 

if you have a 6.5:1 CR and no boost what do you got?

 

where we at? I didn't know we jumped up to v8s with nos and 150psi

 

Who cares about carbed versions of our engine? There's like one person who's ever done that and they are the most hick, hillbilly retard ever to fall into the world of starquests.

 

You are talking about stock cast pistons that wouldn't hold up to the beating a STOCK turbo piston would.

 

I was never talking about low compression as a solution, you brought it up. When you do extensive modifications to the block like a head spacer, longer rods and different pistons, OF COURSE you will give it the appropriate compression ratio.

 

The only reason I mentioned top fuel cars is because it was an attempt to apease your thought process. Get some electricity, carbs and things from the 70's aren't good for performance.

 

EDIT: LOL, well, i went back and read this post, and while I said carbs aren't good for performance, I meant on a turbocharged street car. (sorry!, hehe)

[4bangerT]

And if u want more displacement offset grind the crank, you get better journal oiling. Get yourself some 9-10:1 forged pistons and run the same or more boost.

[PDX87Starion]

Skyline people use head spacers to increase displacement too. You can add stroke to the crank and use longer rods for higher revving etc. There is a kit for skylines that changes the engine from 2.6 to 3 liters.

 

Short stroke motors rev higher, not long stroke. We already have a long stroke "truck" motor with lots of tourqe but lower revs.

 

For example my fiat race motor is 1.3 L. now the pistons are 87mm thats close to the size of the SQ at 91mm. The main difference is the stroke, the Fiat has a very short 55mm (2.16in) stroke compaired to the SQ at 98mm (3.86in) The fiat has no low end torque but revs to 10 grand. (which makes it a relitively good race motor, but gutless on the street in stock form) The SQ, with its long stroke, has tons of low end torque but does not rev that high.

 

And the only way to change the stroke, is to change the crank. Rod length only changes where the piston is sits, not how much it goes up and down. I have heard of offset grinding the crank but that will change the stroke only a tiny amount.

 

Probably stuff you guys already know, but maybe new to some.

 

Ohh, and to decrease your comp. ratio, its easy. Just run two headgaskets!

No just kidding, dont do that!

[Technology]

What I meant was get a stroker crank, but increase rod length more than you increase stroke, and your "new" engine will have a better rod ratio for higher revving. Since a head spacer allows you to do both those things, that's why I mentioned that.

[JamesR]

you dont want lower compression than 7 to 1, your offboost performance will be terrible.

 

agreed. In fact, you probably should be raising our compression a bit. Maybe 7.5 or 8:1

[xtremeboost]

What I do not understand is why do people look for crazy ideas when they haven't even maxed out the owner of their current engine block as it sits; yet they think of investing mass amounts of cash and time into something without even thinking much about it !!! Its been shown that if you "actually" ( actually being the KEY word ) build your car the right way you will have a 500hp car on pump gas !!! We are now maxing out the stock blocks and cracking them just about everytime we run the car but we're looking at around 45lbs of boost and well over 1000hp and that has been done without the use of any spacer . If people invested their time into real research of the 2.6 they may actually have great running cars and NOT just crazy ideas which have ZERO base for actual use in the G54B !!

 

Best Regards

Frank

[4bangerT]

You can actually obtain quite a bit of displacement with a offset ground crank and because of an added sized radius ground into the journals you will have a stronger crank PLUS you have a smaller circle so at higher RPM's less bearing friction. The only tried and true way to get more arm out of this motor, but as stated above this motor does not lack arm it lacks piston size and the ability to create air velocity.