Projekt wrote:since the supras and skylines(i think) are now using 4 cylinders i don't think they're using t88's and if they are, their 10K rpm redline might help. personally i like my powerband to be a touch longer than 2000rpm....

I knew that some supra's were running the 3sgtes but was not aware of skylines were also running 4s. The Jgtc silvias run t78's most of the time.

quick dsm wrote:For my sake in the arguement, i was starting a turbo with a spool time around 4300rpm, not 5k. I believe a 5000 rpm spool is at the limit of streetability.

With that being said, im most cases you are spinning the turbo in day to day driving, more fuel consumption in response to more boost.

1. The JGTC supras run a T88 34d-pretty damn big. I think the skylines use those as well. They must suck for circuit driving.

Very witty, except you fail to realize those are 6 cylinder cars, so they make far more base hp then a 4 cylinder, which give them a high hp starting point. So how would you know how fast they are a track? All you know is that they are faster than your dsm, speed is relative...

2. A lean condition in low rpm will not hurt engine longevity provided you are not detonating.

Wrong again, lean conditions produce more heat the an ideal fuel mixture, running anything lean on a engine with forced induction will detonate. Higher heat causes premature breakdown of oils, and ultimately increased wear and tear on engines

3. Driving around at lower rpms with a larger turbo will increase mpg-smaller turbos will spool sooner causing the engine to injest more air and burn more fuel.

Newsflash, your not driving a CVT, your rpms wont remain constant, and regardless of where your rpms are your still spinning the turbine... even if your not fully boosting your ecu is still sending the signal for more fuel in order to keep the mixture decent, or in your case "lean". Dont tell me you'll never spin the turbo when your around town because you'll keep it down in lower rpms. It aint gonna happen. BTW whats the point of having the turbo if your not going to use it?

4. As far as a car "dumping fuel" the amount of fuel is calculated by the amount of air being drawn in to the engine. When the turbo spools, the engine will injest more air and ad the correct amount of fuel. This happens with any turbo, small or large. The larger unit may be moving more air and using more fuel but the ecu does not just dump it in there. That doesn't make sense. That's why people tune their cars.

If you weren't trying to pick my post apart with your *** you may have noticed that people refer to adding fuel as dumping fuel. Your right, when the turbo spools it takes in more air, which "dumps" more fuel, which means... *drumroll please* you loose gas milage. So with that point down, onto the next.

5. The turbine spins always, no matter what size turbo you have. That's the whole advantage of turbocharging-using otherwise "wasted exhaust energy. A larger turbo will even have less back pressure due to a larger turbine housing.

No thats not entirely true. The turbine vanes take up more space. That means that any extra room has been taken up by the vanes. The bigger turbine has more rotateing mass, making it harder to move/ spin. Why did you think it takes so long to spool? The houseing is not built simply to flow more air, it's built to speed up the air to increase effieceintcy. They are made to lower spool rates, increase pressure and response. Bernoulli would be proud of the turbo.

Now, explain to me, how much do you think you know?I was like you, thought i knew everything, came on here, found out the hard way i dont know squat, and compared to the veterans, Adam, Apexi, Freddy, AZ, Exar-kun, K Car, Maine... i still dont know squat... but i know something, and that something, is that your wrong.

PS Dori Dori, were not talking about racing turbos, those guys also use misfire systems, were talking relatively affordable.

he already said they use antilag, why did you requote him?

using a t78 even on the street is just silly. if you want to do it, go right ahead. personally, i'll stick with exhaust housings T3 and under.

Atta boy projkt

Dori Dori wrote:e. Run at high rpms all the time! We are not talking about auto-x cars that rarely see past second gear.

And the list can go on and on! Come on, take the JGTC out of this conversation. They are nothing like street cars. That goes for Rally cars as well.

I agree 100%... I don't think my 240 is going into JGTC competition anytime soon, so I'd go with the twins b/c I like to auto-cross.

Basically... if you race mostly at the Willow or Sebring, or you plan on drag racing singles would be a good bet for you... more than likely. If you want to auto-cross, or just want low end boost... stay away from twin 3037's and such and big single turbos (which should be the only single turbo replacement for the factory twins... personal opinion).

I almost forgot this topic was about putting the RB26DETT in a 240sx...

Outside of Initial D:rolleyes, most people don't know what a misfiring system is...for the general population, it's called an anti lag system or ALS. Also, those JGTC cars are not using Greddy turbos. For all of you reading that and saying 'what the heck is he talking about'...T78' and T88's are Greddy hybrid turbos. They are hybrids of Mitsubishi TD07's and TD08's...it's just Greddy's naming convention. The turbos used in race cars are not by any means like Greddy's turbos or anything else you can get off the shelf. They are fully custom turbos built to the team's engineer's specifications.

Miishu Faiaringu Shistemu

Dori Dori knows his stuff And projekt is either putting a curse on Dori or thats japanese for misfire system?

Sorry to take so long to reply, been kinda busy.For the claim on 6 cylinder cars, wasn't that how this comparison started? (t88 on a rb26)?As far as the lean argeuemnt goes, you're not running lean enough to start melting parts, just leaner than the rest of the curve. I probably should have stated that but i took for granted that you knew what i meant. The air fuel ratio will still be close to stochiometric (sp?) but the curve under boost is always richer (11.5:1) to gaurd against detonation. I'm sure the jgtc cars do not use off the shelf parts but I know they still run large turbos-that is irrelevant because they were brought up to dispute the whole "big turbos are only good for going straight" thing. As far as the mpg thing is concerned, i know i'm right because i speak from personal experience. When i installed the upgraded unit in my car, my light throttle mileage increased. The orignal turbo (t25) would hit 17 psi around 2150-2200 rpms. The 18g hits 19psi just before 4000 rpm. Driving at light throttle (shifting around 3k) the t25 was always running a good bit of boost. At those rpms the 18g would not be moving as much air. I don't think that's very hard to understand??? Less air, less fuel.

yeah I found when I went bigger turbo the fuel economy was much better and the car was much better not attracting as much poilice attention easier to stay off boost meggala

as far as gas mileage i don't think anyone was arguing that because you're only on boost for half the rev range now that you're using more fuel. they (me) were talking about 225hp on the stock turbo costs less gas than 350 on your 18g

Running lean at all increases part breakdown over time regardless of how small the increase in temperature is... we were talking about big turbos in general after your "better gas milage" statement. Those 6 cyli have good power in and out of the corners because of their displacement, not because of their turbos. Leaner then the rest of the fuel curve? No s***. It would have to be if your not boosting, however even with the correct ecu components you will still run a little rich in order to off set any minor boost.

Not very hard to understand? Your right in a perfect world when gumdrop grow on trees, the theory of less air less fuel would work, unfortunately there are far to many variables for that to happen. Your still thinking inside the box, gas milage cannot e simply summed up into those components.

Meggala great site

GatorS14 wrote:I've seen an RB26DETT in a v-spec blue S14(MC) w/ a bomex body kit.That thing was sweet! I seen it last april and he said it's been in there a year.So, thats going on 3 years this guy has had one in his S14.It has a full interior and 18 inch(i wanna say BBS's)and runs way under 10 secondsin the qaurter he has to tap the brake to get 13's cause he doesn't have a helmet,rollcage,etc.. !what a machine! I'm pretty sure it was still u.s. style steering.And I have seen his ride on the net ,but i dont have the link. I seen him in Gainesville Florida and pretty sure he is somewhere in the south.

That car is my favorite car i've ever seen.<----had to throw that in.:ylsuper

Is it this one? If so that is a RB25det. The Guy is dead and the car was destroyed in an accident btw.

I just wanted to address a few of these issues, and sorry about dragging this back up. Also, I know I only have like 1 other post, but I'm a lurker and don't post much.

--------------------------------------------------------------------------------Originally posted by quick dsm For my sake in the arguement, i was starting a turbo with a spool time around 4300rpm, not 5k. I believe a 5000 rpm spool is at the limit of streetability.

With that being said, im most cases you are spinning the turbo in day to day driving, more fuel consumption in response to more boost.

Not necessarily, see below | \/

2. A lean condition in low rpm will not hurt engine longevity provided you are not detonating.

2.a Wrong again, lean conditions produce more heat the an ideal fuel mixture, running anything lean on a engine with forced induction will detonate. Higher heat causes premature breakdown of oils, and ultimately increased wear and tear on engines

ME -> Lean is relative to engine load is it not? Such as at idle, you don't want your a/f ratio to be 11 or 12, it will be somewhere at 18 or 19. Same with partial throttle operation, if the engine is under a light load, it doesn't need to be rich or at stoichmetric (sp), and your temperature will not skyrocket and reduce the life of your engine even if you drove around like this all day, which, amazingly, 95% of the population does. It doesn't hurt anything if tuned correctly. And thats what proper tuning will get you: good mileage by figuring out how lean you can make it and still not detonate and or reach too high of egt's. But even at partial throttle, your still not going to have as high of egt's as your are under full throttle, so what wears your engine out faster?

3. Driving around at lower rpms with a larger turbo will increase mpg-smaller turbos will spool sooner causing the engine to injest more air and burn more fuel.

3a. Newsflash, your not driving a CVT, your rpms wont remain constant, and regardless of where your rpms are your still spinning the turbine... even if your not fully boosting your ecu is still sending the signal for more fuel in order to keep the mixture decent, or in your case "lean". Dont tell me you'll never spin the turbo when your around town because you'll keep it down in lower rpms. It aint gonna happen. BTW whats the point of having the turbo if your not going to use it?

ME -> I don't know what town your living in, but even driving a 240 with sr20 w/ a t25, if you even hit 1 pound of positive pressure, your driving to fast and will be pulled over. Hell, with a stock ka24de and partial throttle I already drive faster then 90% of the people, and thats shifting at 3500. You don't need 15 lbs of boost to go between stoplights. You do to get to freeway speeds with confidence (love that phrase), but thats about it. After that, you only need boost to go fast, and to me that means your racing. And, if your racing, 1st gear goes by so fast, you probably wouldn't make full boost before you realized your hitting the rev limit. After that, your already in the proper range for 2nd when you shift, and away you go. On the other hand, if your doing freeway racing, if its to hard for you to downshift from 5th, the "lag" you experience is your own fault.

4. As far as a car "dumping fuel" the amount of fuel is calculated by the amount of air being drawn in to the engine. When the turbo spools, the engine will injest more air and ad the correct amount of fuel. This happens with any turbo, small or large. The larger unit may be moving more air and using more fuel but the ecu does not just dump it in there. That doesn't make sense. That's why people tune their cars.

4a. If you weren't trying to pick my post apart with your *** you may have noticed that people refer to adding fuel as dumping fuel. Your right, when the turbo spools it takes in more air, which "dumps" more fuel, which means... *drumroll please* you loose gas milage. So with that point down, onto the next.

ME -> Not to also pick apart your post, but I can see where saying "dumping" fuel would cause some confusion and make it sound like your wasting gas excessively just to further your point. Just because he called you on it because it does sound confusing, you just say "well, what I really meant was this", that just doesn't work. Saying something like using more fuel would be a little less confusing.

5. The turbine spins always, no matter what size turbo you have. That's the whole advantage of turbocharging-using otherwise "wasted exhaust energy. A larger turbo will even have less back pressure due to a larger turbine housing.

No thats not entirely true. The turbine vanes take up more space. That means that any extra room has been taken up by the vanes. The bigger turbine has more rotateing mass, making it harder to move/ spin. Why did you think it takes so long to spool? The houseing is not built simply to flow more air, it's built to speed up the air to increase effieceintcy. They are made to lower spool rates, increase pressure and response. Bernoulli would be proud of the turbo.

Now, explain to me, how much do you think you know?I was like you, thought i knew everything, came on here, found out the hard way i dont know squat, and compared to the veterans, Adam, Apexi, Freddy, AZ, Exar-kun, K Car, Maine... i still dont know squat... but i know something, and that something, is that your wrong.

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Now I don't want to ruffle any feathers, but I think quick dsm did make valid points and I just wanted, to me at least, maybe clarify them further.

93semax wrote:Is it this one? If so that is a RB25det. The Guy is dead and the car was destroyed in an accident btw.

DOH! link is not working, and I wanted to see it too. Any more info about that guy wrecking his RB25 and getting killed? That is crazy..Anyone got any more skyline into 240 swap sites? Not the standard vendor links either please, I've seen them, any personal pages with details etc?

click on the link then take out the http://www. and it should work

here's something that hasn't been bought up yet, and maybe an insignifigant point but one big turbo costs a lot less than two turbos two wastegates etc...for the price of your second turbo you can use nitrous and viola...

hmmm. that's odd cause my friend seans' car is left hand drive and still twin turbo! here's some pics to show ya. stock mounts and no cutting or welding ever done to anything, steering is fine.