11.1:1 + 6psi = x

[TrunkMonkey]

x = i'm tired of the same old same old.

PLEASE READ!!!!!

this is kinda like a brain teaser. it may sound like it, but none of the ramblings about the plans i have posted here are not set in stone. if you can't think outside the box, read no further...and if you do read and find that the only contribution you have is "it can't be done, it won't work, or you're crazy"...don't bother to post.

i just can't seem to get excited about the kat system i have mapped out. why? regardless of what turbo, manifold, how much boost, or what fuel management i use...it's basically the same thing you see on any given day on any of the dozen or so nissan forums/lists. the ONLY real excitement seems to be "i'm making more power than you".

well whoopideedoo.

i need to throw something in the mix. so i've opted to jack up the compression ratio to 11.1:1 with the use of swain coated sohc pistons in a completely stock bottom end. i am limiting myself to 93 octane (no mixing of anything to increase octane rating). i'm not eliminating water/alcohol injection, BUT i do not want to rely on it either.

the biggest obstacle here (besides people whining and complaining about not being able to do it) is obviously heat.

comments? if you do have the urge to post "it won't work", please back up why.

-demetrius

[toki]

11:1 will work N/A on 93, I KNOW 11.5:1 you have to mix higher than 93. 11:1 turbo could maybe work on 93 with multi thousand dollar fuel system, simply because you would have to have very specific maps i'm pretty sure. I don't really think it would be worth it on any level.

[Jonny 290]

Is there any specific reason why you want to specifically make high compression?

If you want to do something different and really piss off the SR guys, destroke it a few MM, bronze valve guides, inconel valves, etc. etc.

turn it into a 2.2 liter screamer

[lessthanjakejohn]

detroked - that be a waste

I love the idea of high CR + boost. It will be the best of both worlds: fast response and higher power. Perhaps you should rely on a thicker headgasket to lower the CR just a tad. Your going to have to have a real nice cooling system.

[Nathan]

I wouldn't rely on a thicker headgasket, but I would go with custom forged pistons just for the strength. You can't afford to make a tuning error with stock pistons that are high compression and boosted on. I think it could be done and would be a heck of a cool, fun car. I think you know what it'd take to run that in terms of engine management I say it's very doable!

[lessthanjakejohn]

Whats the price rate?

E pistons + Swain vsquality forged vsquality forged + swain

Because if you **** up a 500 dollar set of pistons your screwed.

If you did go with forged, Wouldn't you want to go with a lower CR because you have a choice? Perhaps 10-10.5 would work out well.

[TrunkMonkey]

11:1 will work N/A on 93, I KNOW 11.5:1 you have to mix higher than 93. 11:1 turbo could maybe work on 93 with multi thousand dollar fuel system, simply because you would have to have very specific maps i'm pretty sure. I don't really think it would be worth it on any level.

multi thousand dollar fuel system? very specific maps? i don't think so.

if jwt will tune the ecu with their usual pig rich tendencies, then i can use that as a starting point, and fine tune with an safc.

i've got a line on a couple of spare engines, and sohc pistons along with the swain coating are pretty cheap. if the ka's bottom end can hold 15psi, then i'm confident it can handle a high compression low boost setup.

yes, if i did go with forged pistons, then i would probably run 10.5:1. but the price of the sohc pistons puts it on top.

besides, there's a big cool factor that comes with using an oem part as an upgrade .

-demetrius

[Jonny 290]

man, if you got the spare blocks lined up, GO FOR IT. I'd love to see the KA crew show everybody up who had previously been screaming "9.0 or lower! 9.0 or lower!"

[toki]

i said multi thousand simply because I personally wouldn't try it with less than a full standalone. Maybe not multi-thousand, but i've seen top notch standalones go for atleast a grand. if you have the room for error, feal free to trouble shoot it by yourself, more power to you.

[andrave]

why not get forged pistons? the sohc pistons have ****ty ring lands and aren't going to take any detonation... besides with forged you could go with a more moderate compression, like 10 or so.. 11 is just really, on stock pistons, on a street car

[TrunkMonkey]

why not get forged pistons? the sohc pistons have ****ty ring lands and aren't going to take any detonation...

the sohc and the dohc piston are identical except for the dish dept in the top. both have the same crappy ring lands. besides with forged you could go with a more moderate compression, like 10 or so.. 11 is just really, on stock pistons, on a street car

use a lower compression ratio? kinda defeats the whole idea doesn't it .

-demetrius

[Checkered-Member]

Lets take the example of the Acura RSX-S with it’s 11.0 compression, people have been turbo charging it since it came out, with 4-6psi

Most of them run just 91 octane (not even 93) oil coolers, upgraded fuel system, stand alone and **professional tuning**

That it…

so demcj want 6psi at 11.0...talk to some RSX-S guys

[SSS]

I would love to do this also, but i'm not that game. I would strongly recommend hypereutectic or ideally forged pistons if you plan on running less than 93 octane, it will need to be as detonation resistant as possible. But if you have several spare engines, go for the coated OEM parts.I'm still a tad worried about running 5 psi through my sohc motor on 9.0:1 cr and 98 octane, with 4 550cc/min secondary injectors and 1 deg ignition retard per psi.Personally, i would go for a programmable piggyback setup and not a JWT/SAFC combo, my reasoning behind this is being able to datalog what's going in and out of the piggyback unit (E-manage, SMT6 etc), mainly AFR numbers.What turbo do you plan on running, and are you going to use a log or equal length manifold?

[TrunkMonkey]

i'll be using a t04e 60 trim.

as for the manifold, i'm waiting to see the finished product that ssautochrome puts out for the ka. the prototype looks very promising. it's either that or a revhard.

-demetrius

[SSS]

Well you can guarantee that with an equal length header and the high comp the turbo is going to spool quite quick, i'm betting on the full 6 psi being available from around 1900rpm or less. Also, whatever steps you take with treating the pistons, get them cryogenically treated. It's a cheap insurance policy and should strengthen those weak ring lands nicely.

[andrave]

Yes, and its common knowledge that for daily driver street use, the ka24de pistons are far from ideal... run into detonation one day, replace the pistons the next. So how do you figure that you are gonna be fine if you increase compression by 3 points, thereby increasing the risk of detonation?going with a lower compression doesn't defeat the whole idea... its just that you could stick with your idea and have a more stout engine to turbo if you went with something like 10:1, which is even higher than stock, and you would have the advantage of stouter ring lands and rings...oh well, its your money and time, and it could work fine, it just doesn't make sense to not use quality parts when you get the chance to upgrade.

[TrunkMonkey]

So how do you figure that you are gonna be fine if you increase compression by 3 points, thereby increasing the risk of detonation?

3 points? who's raising their compression 3 points?

i'm gonna break one of the rules of this forum. as knowledgeable as you may try to seem, you REALLY need to use the search function.

-demetrius

[Checkered-Member]

it just doesn't make sense to not use quality parts when you get the chance to upgrade.

well if something blows up...and we all know how likely that is...replacing various parts is WAY cheaper...plus I guess he has a few spare engines just laying around...

[TrunkMonkey]

Lets take the example of the Acura RSX-S with it’s 11.0 compression, people have been turbo charging it since it came out, with 4-6psi

Most of them run just 91 octane (not even 93) oil coolers, upgraded fuel system, stand alone and **professional tuning**

That it…

so demcj want 6psi at 11.0...talk to some RSX-S guys

i'm not sure i want to talk to any of the rsx-s guys you're refering to seeing as how none of the rsx's bolt on turbo/supercharger kits require a stand alone or professional tuning.

-demetrius

[andrave]

mwha haha the mods are breaking their own rules.I'm saying 11:1 is higher than 9:1, you said yourself thats what everyone else recommends for a turbo.

[TrunkMonkey]

9 + 3 = 11

seriously, since you don't know, the compression will be raised 1.6 points.

and when did i say that everyone recommends 9:1 for turbocharging?

-demetrius

[C-Kwik]

With a good efficient turbo, it's possible. 6 psi is not a whole lot of boost so it probably won't be a problem so long as you don't detonate. The response should feel pretty good with such high compression as well. Maybe back off the timing a bit and work your way up.

[andrave]

sorry that was jonny 290, got confused.

and my math is bad.

give a guy a break...whatever, I'm done bickering. Do it, if it works then it works. And maybe others will follow your lead. I have the pieces to do it, but not the motivation.

just how much hp and how much boost are you planning to run

[dareo]

Audi is running 9.8 CR in their TT 4.2l V8, peak torque just off 2k rpm. I'd say you can do it if you have good fuel and timing management and tune it perfectly. Once you have figured up a management solution, such an engine would be incredible. I dont even want to think about how much you would need to spend.Once you got it all working, you might even be able to tune higher than 6 psi.

Plan on breaking stuff, and good luck to you!

[Checkered-Member]

i'm not sure i want to talk to any of the rsx-s guys you're refering to seeing as how none of the rsx's bolt on turbo/supercharger kits require a stand alone or professional tuning.

-demetrius

If you are referring to Greddy they come with e-mange and a custom fuel map, so no tuning needed, stand alone is used with custom turbo kits at least I have seen half a dozen turbo charged RSX-S with stand alones…so I guess stand alone might be an over kill on some occasions

[deviousKA]

this isnt a bad idea at all. I have yet to see a higher compression ka turbo with lower boost so its time to fill the void. I see no problems other than detonation issues. I havent heard much of the full benefits of coated oem pistons but i would think you will be wanting to go forged.

btw. If you want forged pistons to gain 11:1 cr in de, for very good price. I can let you know how to do this for under $300

[TrunkMonkey]

[quote=" andrave just how much hp and how much boost are you planning to run [/quote]i'll start off with 6psi, but i have no real hp goal set. iirc, there's a kat that put down close to 230whp @ 6psi with a to4e 60 trim, jwt ecu, and safc. i'm not sure how well tuned it was, but that kinda gives me a starting figure.

-demetrius

[ChildDamien]

id say try it, because you have spare shortblocks? laying around...but i cant think of it right off the top of my head but as far as science and math go, whats the compression going to be on the rotating mass of the pistons, ring lands and rods at 6psi on 11.0:1 compression, id say if it is close enough to 8.5:1 or 9.0:1 at 12-15psi youll be fine, and could in theory use the same fuel setup as a car with 9.0:1 compression at 15psi.....but thats only if the numbers line up......as a precaution id say run the numbers( if you can find the equation) just to be safe....and then that would give you a good starting point...

and just tie the whole point together.... your starting compression + whatever PSI your running on turbo = much higher compression on rotating mass.... and people may have already known this...im just clearing things up

[Red Lightning]

With a efficient IC and alcohol injection, I don't see why you can't run 6 psi on 11:1 CR. Comptech made a S/C for the S2000 (11:1 CR).

[TrunkMonkey]

With a efficient IC and alcohol injection, I don't see why you can't run 6 psi on 11:1 CR. Comptech made a S/C for the S2000 (11:1 CR).

comptech, vortech, and a couple of other companies that make turbo kits for the S2000 all boost around 7-8 psi on straight pump gas. no alcohol. that's the goal here.

-demetrius