A new way of thinking... T2-low boost-high compression

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SX APPEAL
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Just an idea I've had because I'm weird and like to reinvent the wheel lol.

So what if you built a KA with E pistons -11.2:1 compression, and then boosted it at no more than 6-7psi, maybe a little more with race gas. A T2, especially a higher end one will spool that much practically at idle, but you'd get so much more power per psi with the high compression. So in theory, if you could tune out the knock, which would be the hardest part, you could have an extremely responsive 2.4L engine capable of 250, possibly even 300whp by 2-2.5K rpm. Tell me that wouldn't be fun...

EDIT: I think we've come to the consensus that expecting 250-300whp by 2.5K rpm is completely unrealistic, and was an ignorant thing on my part to suggest, given that a 2.4L engine simply does not move enough air at those low rpms to produce such power. But the concept of extreme responsiveness, full boost at extremely low rpm, and much higher horsepower per psi, I believe still stands.

...if you could make it work lol

ok now your turn to tell me why it never would :chuckle:
Last edited by SX APPEAL on Mon Feb 28, 2011 1:16 pm, edited 1 time in total.


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eazye2000
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It would work, in theory. I just haven't seen anyone do it.

But I would assume someone should piece together a stock motor with the E pistons and try it out. With some bigger injectors and E85, I don't see why this couldn't be possible. Might be a bit stumbly off idle, but after she catches it should run like a raped ape.
But tuning would be key for this setup.

If I find an E motor, I'll snag the rods and pistons and build one. I have a ton of gaskets and a few blocks laying around. And with the market for my T2/3076R, I might have it for a while, so I might try it.

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neverlift
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had the option to do that but with my t3 setup.


I might still get the rodspistons off my buddy but it would be an all motor type build. I dont think a t2 flange is the way to go however.

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Crazyirish
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The idea definitely has merit, but you're dreamin if you think 250 whp at 2500 rpm is anywhere in the realm of possibilty for a ka with a t2.

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yeah reading back over that it does sound a little far fetched lol, since horsepower is a product of rpm, but suffice it to say it would be at full boost by 2K.

I'd love to be able to try it, but with only one 240 that has to be a daily and limited cash flow, its not gonna happen for me. Glad some of you guys are taking it into consideration tho :dblthumb:

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hannibal
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It would have tons of torque, not HP.

And it would likely explode after 5000rpm...

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eazye2000
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Haha, another boat load of people saying T2 wont work, blah blah. I'm proof of 500whp with a T2. Enough said about that...

All said, it's in tuning. Regardless of what f*** turbo you use. It's like supercharging something like a factory S2k, or an Si Honda. But not even a supercharger, hence the 'T2 turbo' mentioned for the fast spool. Tune it, and it will work. Plenty of production vehicles out there right now with this same exact thing the OP is talking about. BUT, with the aid of race fuel; or E85 being my favorite, and forced induction.

There are plenty of threads out there with other setups that do pretty much what the OP wants. Instant boost (with a supercharger), and using high compression pistons, all while running a 'race fuel' or something with a higher octane. No, you can't just slap something together; and unfortunately you need to know what you're doing.

You will probably not have high horsepower, but a crap ton of torque early in the rpm range. You will have to choose cams accordingly to do this, and degree for the powerband you want. And you wont be able to rev very high, and/or be very efficient past a certain point. Look at some of the road racing and autocross cars dyno charts. You'll see 250 whp at something like 3k, and it will go flat all the way to like 7k. They can't make over 250whp, but they make it early, and tune for it for the rest of the powerband.

Here's a final example if you can't make heads or tails out of my ranting post. And this is generally speaking with any boosted motor:
You run 20psi of boost on pump gas, and make 200 whp. You then run 50psi of boost on pump gas, but only make 300whp because you have to (slam your baby on a concrete curb headfirst) retard the hell out of your timing so you don't detonate. There becomes a point to where you are adding so much more boost, but not getting any power because you have to dial back timing.
Now, said guy comes back with same motor and wants to run 50psi again; BUT, he gets smart and runs race fuel (or my fav E85). Now you're cooking with fire because you can start to advance your timing, and guess what.... MAKE POWER because you're not dropping your kid on the curb again... ( i really hope this is ringing some bells here )

Now the same concept is applied for raising compression using a constant fuel source. (without boost)
You dial your 'all motor' 9:1 compression 'beast' in within the threshold of knock; all while using 'pump gas'.
You then raise your compression to 10:1 - This is a problem because your tune is dialed in for 9:1. Well now you have to (again, drop your child), retard your timing or you get knock/make less power.
Well we all know that if you raise your octane, you get rid of knock, right? So in order to run the same timing, but only change/raise compression, you now have to run a higher octane fuel.

Now lets put this recent 'boost' and 'compression' lesson to light when you combine the two:
Raise the compression of your motor, and boost it with pump gas. Well, usually a bad combo when you leave your timing alone. Well, lets say we tune the motor for 'high compression, with boost'. All you pretty much do, is pull a crap ton of timing, and the car will run; and run rather well when tuned.
Now lets say we have the same boosted, high compression motor; but use a higher octane fuel. Well, we can advance the timing and start making power out of it before detonation/knock becomes our problem from which we originally want to tune up to/but not pass the threshold.

I'm giving up past this point. I'm tired of trying to explain this to people who haven't had a hands-on with some of the stuff they put their .02 cents in on. I think that's why I stay off the internetz anymore, and stick to what I know with hands on experience.

*I look forward to your letters* :ohno:

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What exactly was your point?

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eazye2000
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Crazyirish wrote:What exactly was your point?
I guess you skipped the whole post. If you don't understand it, then don't clutter the threads.

Basically, it's been proven time and time again, that high compression, boosted (turbo/sc) motors are out there and are prevalent. They are more common than you think.

Ok, try this. Use your favorite search engine, and go read what people are doing; not what you think can or cannot be done. There are high compression, boosted motors, that also run nitrous. See if you can squeeze that into comprehension.

There are many ways to do it. Omit race/high octane fuel, and run water/meth injection instead, etc. etc. etc... But it's been done for years, and it's nothing new.

In a nut shell, yes you can boost a high compression motor. With any form of forced induction you choose. And as with any motor tuned to make the most power without grenading, it's going to require that you tune it to the octane fuel you are using. Isn't that simple? :drool:

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Crazyirish
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eazye2000 wrote:I guess you skipped the whole post. If you don't understand it, then don't clutter the threads.
If you're point was that you're coming off sounding like a jerk, then, heard.

The OP wasn't trying to revolutionize the way people build forced induction motors, he was just theorizing what a relatively low budget build would be like if he went a little against what conventional wisdom says to do with a ka.

But thanks for coming in here and letting us mere mortals bask in some of your experience. No really. Do you have a paypal I can send some $$ to?

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SX APPEAL wrote:Just an idea I've had because I'm weird and like to reinvent the wheel lol.

So what if you built a KA with E pistons -11.2:1 compression, and then boosted it at no more than 6-7psi, maybe a little more with race gas. A T2, especially a higher end one will spool that much practically at idle, but you'd get so much more power per psi with the high compression. So in theory, if you could tune out the knock, which would be the hardest part, you could have an extremely responsive 2.4L engine capable of 250, possibly even 300whp by 2-2.5K rpm. Tell me that wouldn't be fun...

...if you could make it work lol

ok now your turn to tell me why it never would :chuckle:
Its not that it won't run but choosing too small a turbo generally means you run out of turbo before redline. Basically, the efficiency gets so bad that you turn the turbo into a heat pump. You are still going to want to compare the turbo's compressor map to the engine and try and match it up well for the intended boost curve.

As for making 250 HP by 2500 RPM, you are talking about making 525 lb-ft of torque. Neither higher compression nor 6-7 psi of boost will get you anywhere close. There is just not going to be enough air at that boost level to bring you close to that figure out of 2.4L of motor. Understand that higher compression doesn't "make" more power. It just converts the energy from combustion of a certain mass of air and fuel more efficiently into mechanical motion since the expansion ratio of the motor is higher (same as the static compression ratio in most motors).

Lastly, matching higher compression with boost can still detonate fuel even at low RPM's. Ignoring heat loss differences during the compression stroke (my guess is the difference would be minimal anyways), you're still compressing about the same amount of fuel and air by the same amount at different RPM's.
eazye2000 wrote:Basically, it's been proven time and time again, that high compression, boosted (turbo/sc) motors are out there and are prevalent. They are more common than you think.

Ok, try this. Use your favorite search engine, and go read what people are doing; not what you think can or cannot be done. There are high compression, boosted motors, that also run nitrous. See if you can squeeze that into comprehension.

There are many ways to do it. Omit race/high octane fuel, and run water/meth injection instead, etc. etc. etc... But it's been done for years, and it's nothing new.

In a nut shell, yes you can boost a high compression motor. With any form of forced induction you choose. And as with any motor tuned to make the most power without grenading, it's going to require that you tune it to the octane fuel you are using. Isn't that simple? :drool:
Many modern high compression motors are used in high performance applications. And most high performance motors these days use neat technology that varies valve lift and/or timing. They can be used to change the dynamic compression at higher RPM's and loads such that the actual (dynamic) compression taking place is smaller than the static compression suggests, say by delaying the closing event of the valves as the compression stroke begins. A cam swap can certainly make this possible, but chances are, the available cams that can allow for this on a KA is likely to have their most powerful point of operation diverge with a smaller turbo's peak efficiency range. A late valve closing event at low RPM's can cause quite a bit of havoc if there is a lot of reversion back into the intake. At higher RPM's the airflow is faster so it becomes harder for the air inside the combustion chamber to push the column of air in the intake backwards. But since the OP is speaking of trying to maximize lower RPM power, then such a set-up is likely not going to be ideal here.

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eazye2000
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Yeah, my apologies for getting bent out of shape. I'm rather tired of typing the same things over and over again, in different forums all over. A simple search engine could have pointed some of the interested parties in this thread to the wealth of information out there on the internet.

The topic at hand is one of the more difficult ones to explain. And I have a hard time trying to explain things. I don't have a problem trying to explain something, but I hope the end user has an ample amount of time on their hands to listen.

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neverlift
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well then eazy stop trying to make the world stand behind YOUR logic. I am not a boat load of people, but I am one guy that has ran a t2 and a t3. The t3 wins brother. I have a VERY lack understanding of compressor maps so I go from what I know, yes a t2 can make good power, but a comparable t3 will probably make more on the same setup.

Imagine running your a** off, its hard to breath(only turbo that wouldnt be a restriction on a ka is t4 or larger lol)and you only have 2 options for air. Would you want a coffee stir straw or a hardees wideboy straw to breath through?

A ka keeps making power(albeit minimal) with larger exhaust diameter. Its restricted as is before you put a tiny flange and restrictive turbine wheel. I understand your thinking man, doesnt make you right. :p

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Well, you also have to look at Eazye2k's setup. He uses the "Big Boy" T2 combined with an external wastegate. That pretty much negates most of the downsides of a 'typical' T2 setup. Of course it also negates the upsides of a typical t2 setup (lower cost and off the shelf parts availability)

Whats funny is this thread was never intended to be a t2 vs t3 thread (we already have plenty of those). I just said that a KA with a T2 couldn't make 250whp at 2500rpm. What I should have said was that a KA isn't going to make 250whp at 2500rpm with any setup.

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eazye2000
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I will agree that you won't make the 250whp at 2500 rpm. But I would instead try to use a supercharger since they are becoming more available, and easier to mount/install. But I do not know any numbers or specs on when boost starts, comes on, or how much air they move, etc.

s*** almost gets personal when people talk smack about my T2's. My apologies. Not that it happened here, but I hate when it's the people who have never owned one and spout off 'what they have heard or read' online. I instantly take it to heart, and defend my little hot potatoes honor.

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Nothing wrong with loving your own setup :)

I like the supercharger idea, but all of the setups I've seen put the supercharger right on the intake manifold, ergo, no intercooler. If you can run e85 or water/meth injection then sure, but I'd rather have an intercooler.(At least if I was planning on running anything more than 6-7lbs boost) You could remote mount a centrifugal supercharger, but then you're losing the benefits of the positive displacement blower. At that point, why not just turbo?

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no eazy dont take what I say about t2 too harsh(I fvckin loved my t2 setup!!!)

a big reason I would not choose a t2 on a high comp ka is temp, a t2 becomes a heat pump on a ka at 10psi, if you add high comp to that it would be more like 5.
I mean on e85 maybe it would work, but you would be talking 1000+cc injector to keep knock under control. A larger t3 would make charge temps lower making knock eazier( :gapteeth: ) to contain(feel the IC on a t2 setup and a t3 setup). ANYTHING is possible(except getting a ka over 200whp na without 30k budget) but if you have sohc pistons you would be looking at more of 12~13.5:1 comp ,already on verge of non pump gas(without tons of timing pulled).

I know eazye is in the exception rule when it comes to t2's,but his snail cost more than the entire time I have been boosting. And thats 4 or 5 turbos and 4 motors/rebuilds.


btw crazyirish the external and uberlarge ext side only make up for part of the t2 size debate. Still have a tiny inlet flange(stir straw vs regular straw)...

hmm a supercharger might work , I dont care for superchargers mainly in the respect they rob power before giving anything,then the max boost at redline really puts me off. Making more boost longer just makes more sense to me. Man I love nico

Not taking anything too harsh its teh intrawebz

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neverlift wrote:btw crazyirish the external and uberlarge ext side only make up for part of the t2 size debate. Still have a tiny inlet flange(stir straw vs regular straw)...
More like a small stir straw vs a smaller stir straw. :) Gimme a 3" v-band!
neverlift wrote:hmm a supercharger might work , I dont care for superchargers mainly in the respect they rob power before giving anything,then the max boost at redline really puts me off.
Keep in mind that most supercharged ka24s are using a positive displacement supercharger. They produce full or near full boost right off idle.

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yeah that is true crazy, didnt even think about that. But a proper sized t3 can also produce full boost not too far off idle. I am not familiar enough with superchargers to debate them.

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Dunno how I missed this thread...

You could easily run high compression if you're willing to step outside of the box. Probably 10-12 psi and 350whp. I'm cooking dinner but I'll be back...

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WDRacing wrote:Dunno how I missed this thread...
WDRacing wrote: I'm cooking dinner but I'll be back...
You answered your own question, you fatty... :facepalm2

Good, because I'd like to hear what the man has to say about this. lol

I was just talking to my buddy about this yesterday. Low and behold, he pulled a GM 3.8 and a T-Bird Supercoupe supercharger out of his closet. Looks like we're doing a 4.0-HO SC project on his 92' Ranger. If I can find a way to tune, I'll update. If not, I'll post pictures of utter failure. He also has a '97 5.0 Explorer that might be a candidate, also...

/jack

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I know what wd will say water/meth injection. The s*** is awesome.

before a sc the ranger should be decent on power(buddy had a 4.0 swap'd ranger,bagged and just sick). But the sc 4.0 would def rock pics or it didnt happen

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Nothing absorbs heat like water. A variable flow system that ramps up the water injection as load increases would be perfect. They have controllers that use the MAF voltage to regulate the pump output. I'd recommend a twin jet/nozzle system so it can be turned on early and still be at a high pressure. So the water will be atomized better. Plus it will allow plenty of volume at max boost. Have it come on a 2 psi and ramp the curve accordingly. You'd need a reliable EGT gauge. You can put one together for under $100 if you buy the parts and the gauge separately.

The controllers they have available today can do almost anything. Retard timing if the water runs out, datalog the whole shebang.

I was thinking about a NA build but I would mill the head as well so I could have a 14.5 or so compression ratio.

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So ressuracting a slightly aged thread here but me and a buddy of mine are soon to take on this endeavor. Were doing an h/c de motor with an s15 t28, a set of deatsch 750's, z32 maf and a JWT rom tune. i think with conservative timing and proper fueling theres nothing wrong with this idea at all. s2k guys boost theirs all the time and iirc theyre 11:1 or higher comp

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Keep us informed.

Just a word of advice though, if you have any means of using software to tune it properly in real time on a dyno, then please go that route. I'm using a mail order tune myself for my turbo project and I don't see anything wrong with them for something as generic as a T3/T04E/550cc/Z32 setup like mine, but with something as unique as what we're talking about here, with all kinds of unknown factors and some really hairy ignition timing needed, I'd strongly urge against it. Something like this definitely needs to be tuned professionally in real time IMO.

Also don't cheap out on injectors, deaschwerks aren't purpose built 740's, they're drilled from lower flowing injectors and have inferior spray pattern characteristics, some tuning companies wont even guarantee their tunes with deaschwerks injectors. For an engine as high strung as this one would be as far as detonation control, go with something proven like Sard or HKS.

Definitely excited to see someone try it though :dblthumb:

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im pretty sure if you specify comp ratio they can correct timing to prevent any ping. an safc 2 with the knock display and a 10mm should make dizzy adjustment very easy and along with conservative timing maps in the ecu we shouldnt have any prob. again, s2k guys have been boosting their 11.x:1 comp motors for how long now so we kno it can be done reliably and safely. give it time tho, i have 2 other customer projects before i start on this one but ill deff bring this thread back and post pics/info/ect for everyone.

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Bringing this thread back from the dead again...

Still been tossing this idea around ever since I brought it up months ago, didn't think I'd be the one pursuing it though. But alas I'm scraping together parts for a build and I think I've got a pretty good baseline here for a high comp turbo KA. Let me know what you think.

GT3076R .63AR
JE Forged 11.0:1 pistons
Fully built bottom end/ ARP hardware etc...
head gasket: not sure, go with a felpro as a sort of safety valve, so that if the engine does grenade, it'll be the HG and not a ringland or something. Or should I go all the way with one of those new Cosworth HG's somebody posted about recently?
Most importantly: water/meth injection, looking at a couple of different systems from AEM and Snow Performance.
Later on: E85 with larger (1000cc+) injectors, retaining water/meth, and more boost and timing.

I've already got an Enthalpy tuned ecu for my 550's/Z32 maf. Can this be retuned on a dyno for the high comp? Never had anything tuned on a dyno before. Like I said, let me know what you think. Gonna need a lot of help on this one.

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Felpro ftw. Check out Cooling Mist.

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Their stuff looks pretty good, a bit cheaper than snow performance too and with more features in the kit. Whats I'm really lacking now is info on tuning with water/meth, is the amount of flow needed based on EGT's? or do you just keeping adding water until it stops pinging lol? WD, got any good links for this one?

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That info will vary depending on engine/compression/boost/cubes etc. I started by reading everything I could find, mostly on the Grand National forums. Those dudes have been using alky for a long time. The first major decision you'll have to make is whether or not you're going to run water alone or a water/alky mix. Methanol isn't cheap these days. You could use windshield washer fluid, whatever has the lowest freeze point = more methanol. Point being, you want your tune to be consistent. So whatever you decide, that's gonna be it. Which is why I'd lean towards water alone. Hard to beat readily available and free. But that's on you. I can assist with the tuning side once you figure out what exactly you're going to use.

I'd also look into a knock meter that has an alarm.

WD


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