keep-on

hi i just wander what is more good for the engine a set up that develops 400hp working at 1,0bar(14,5psi) with a big turbo or a set up that develops the same hp with a smaller turbo working at 1,5 bar(21,7psi).Which is more economy and wich is more reliable.

ALPSTA

iTrader: (3)

Anestis, I'd say the big turbo with low psi would be better and more reliable. Two small turbos will generate more heat. As for fuel economy whichever makes less power that'll be more economical, since more air + more fuel = more power On the other hand small turbos will be on boost more then the big turbo in everyday driving so it's a catch 22 I guess.

If this question was specific to RX7 then i'd never run 22psi twin turbo setup in my car cause I don't see the point.

bajaman

GENERALLY speaking, the 1.0 bar setup is going to be more reliable.
However, there are lots of ways to go about getting big horsepower with a variety of turbochargers, injector set-ups, intercoolers, water/methanol injection....the list is huge.

Personally, I would stick with sequential twin turbos using BNR units. Pretty easy to get 400 hp with the right fuel and intercooler setup, and you wouldn't have the turbo lag that a big turbocharger could have.

Perhaps posting on the single turbo sub-forum might get you some more answers.

Good luck!

BonesZ33

iTrader: (5)

single turbo, twin scroll

Buy the right single turbo and it will be better than twins

fendamonky

iTrader: (6)

I'm running right around 400whp (American figures, 340whp on a British dyno) at 1.2bar with my sequential BNRs, I've got to agree with Bajaman regarding 400 on sequential twins. They are absolutely NUTS.

I think the answer boils down to what you will be using the car for though... Personally my 7 is street driven and has been the DD for years, with that in mind I much prefer the twins since the power is there immediately for stop and go/city driving.

keep-on

Sorry guys,when i said a small turbo at 1,5 bar i meant one small turbine .I've already the t04z on at 1,0 bar and i ask you if a smaller turbo at higher boost is better.

ALPSTA

iTrader: (3)

Oops, still a small turbo at 22psi boost will be blowing hot air, GT35R and maybe RX6 is the smallest I'd go on a RX7. If anyone running a smaller single turbo at high psi they can chime in.

I don't know much about T04Z but are you not happy with it? Is it too laggy?

junito1

what is better for the engine.

Low boost is good.
Cold air is good. (big turbo and low psi = cooler air)

Mahjik

iTrader: (1)

A smaller turbo at higher boost generates more heat. The idea is to keep the charge temps (as well as overall engine temps) as low as possible. Basically, use the largest turbo at the lowest setting which will deliver the performance you require for your needs/wants.

no_more_rice

"Water injection and you're good".

- Howard/Rich

keep-on

thanks everybody i think the t04z have good range of power from 400hp to 500hp depends on psi and the extras you 've got on.

junito1

water/ meth just complicates things. even though it works and makes engines temps go down.. why not just have the proper intercooler/turbo system? doesn't that make better sense than going around the problem with another mod?

Your mom never taught you to "keep it simple stupid"
The more you add the more you will have to monitor. ANbd the more can go wrong.

cool engines = reliable engines.

arghx

iTrader: (3)

you're going to have a broader torque band on a smaller turbo with higher boost. Look at all the 4 cylinders running smaller turbos in the 20-25psi range. They use their highly sophisticated OEM boost control systems to map a tapering boost curve for increased mid range.

WaachBack

iTrader: (21)

This is sometimes true, but not in the case of A/I. A/I is the best thing you can do for a rotary, no matter what your goals are.

GoodfellaFD3S

iTrader: (213)

Gonna have to disagree with you about the AI. Everything you say points to *using* AI, then you say it's just too much of a bother. You're speaking in theoretical terms, do you have any real world experience?

I've been running Aquamist 1s (their simplest system) for over 4 years now with zero (zero) problems. No clog sensor, no level sensor, no electronics at all. It just works.

And it allows me to push my 500R safely to 20 psi on 93 octane. The 500R basically has a T04Z compressor wheel btw.

rotory4life

I have a GT35r. Running with water/ meth, 17PSI 93 oct, and i'm at 400HP at the wheel.

junito1

yes i said the cooler the engine breaths the more reliable

but who said AI was the only way to keep temps down is all im saying.

BIgger turbo and intercooler alone will help tremendously. Maybe you can do a simple air to water intercooler core for around the price of a meth kit.

Did you guys read the thread with the semi-peripheral 6 port n/a engine making 500 whp on 93 oct. alone https://www.rx7club.com/time-slips-dyno-128/88-500-hp-6-port-google-page-ranking-884264/


All im saying is give this kid some options... dont just let him think that AI is the only option. Tell him all the options and let him make his own mind.

junito1

I though e85 was the best thing for a rotary as all the big dogs have been proving.

ErnieT

iTrader: (2)

Once again, you spew the most idiotic mis-information on the forum. You continue to speak of what you know nothing of. How much experience do you have with water/meth injection? Probably as much as you have on drag racing but you give all your infinite wisdom there too. Do everyone a favor. If you personally have no working first hand experience, then just read the thread. Let the people with actual experience give their take. Rich forgot more then you know about making a reliable engine. Water/Meth injection is the best thing ever for a rotary to make in more reliable. Your intake charge air temps will drop like a rock, thus allowing for either more boost or a nice engine you can just beat on and not worry about.

junito1

so you calling me an idiot now?

i tried to give a non bias opinion. about the different routes he cant take. I Might of not hit my comas and periods properly but i know meth is not the only option. Its all im saying.

And for calling me an idiot i must remind you of your awesome achievements.

You are just a baller who cant drive., THis is is how i will always remember you. And so do many others who dont care to express, but THEY KNOW!

MAny inexperienced younger guys in the forum can outdrive you. so sad... you werent too happy when the TurboR1 by enzo rubbed it in your face MUAHAHAH! it took him 9 to 10 run to make it into the 9's you have had his HP level if not more with a way better suspesion setup and still took you FOREVER! <-- i do read see

experience in your case... means nothing,

ErnieT

iTrader: (2)

First, I never called you an idiot. I said your spreading idiotic wrong information, which you were.
Second, You say your giving a non-biased opinion? Based on what?! lmao..your apparent lack of knowledge of the subject at hand.
Third, Don't worry about me. I slapped on a cheap suspension and cut 1.40 60' all day
Fourth, Anthony (TurboR1) and I are friends and make the same power. Once again, do your research before you spout off.
Last, I don't need to prove myself to some child such as yourself. I have done so by what I've accomplished. Now grow up and heed my advise. Stop spewing the wrong information to forum members.
Back to the subject at hand, Keep-on- Do a search on Howard Coleman. He has a vast knowledge on any meth/water injection question you may have and the realiability factor it brings with your motor. Good luck.

junito1

how much more experience could you have than me?

Isnt the majority of your car bought not built? I just dont have the baller funds to purchase a 9 second engine.=P Ive done me share of engine swaps on nissans and 7's.

DO you yourself use AI? or just e85? WHat fuel or method are you using to keep AIT's down? For some reason i got a feeling you use e85 alone... you dont even use AI do you? IF this is the case.. than CASE CLOSED!

And who care if you and turbor1 are friends.. and make the same power. It just proves how much more of a driver he is compared to you since you both have same setups.


and im giving wrong info eh? AI = lower intake temps true. does a bigger intercooler make lower temps too? yes..Does e85 do the same? YES. so was i wrong for saying so? I never said one was better than the other. I just tried to explain the diff ways of lowering intake temps.

ErnieT

iTrader: (2)

Since you are a child, you must have everythings spelled out for you. I do not use E85 nor have I ever. I use gas with meth/water injection so my experience with it is more than say....YOURS, lol. I've used straight water. Straight meth and 50/50. A bigger intercooler will not do nearly as good of a job. Water is great because it does not burn. Thus, acting as a displacment adder (making more power). It also cools the apex seal, preventing warping. The meth cools the charge temps drastically, by almost 1/3 in some cases. Do not post anything else unless its going to contribute to the thread. BTW...my car is all built. lol..Don't assume. You know what thats does...

Dudemaaanownsanrx7

iTrader: (23)

I also respectfully disagree junito1. At a certain point cooler intake temps is not enough to control knock inside the engine. The heat generated inside the engine just by the higher boost and higher power levels is enough to auto ignite pump fuel. By adding water/meth/e85 you are not just reducing intake temps you are cooling and controlling the burn inside the combustion chamber. This allows you to push the engine even further and make the additional power reliably.

I can about guarantee my engine wouldn't have survived the last year at 23 psi with just a good intercooler and cooling system alone. I can also tell you from first hand experience that I experienced more knock in low boost on the ramp up, before my injection kit kicked in. Granted the knock wasn't at dangerous levels but to see the knock spike to 34 on the ramp up and then level off at 20 under full boost (23psi) is proof that the water injection was doing it's thing.

The other advantage is every time it sprays into the engine it gets steam cleaned. No more carbon, which is also a major source of pre-ignition.

To the OP, I would say the bigger turbo at lower boost is more reliable then the little turbo at higher boost. Of course this also introduces more lag.

The best thing to do is pick a power goal, then pick a turbocharger that is most efficient at the boost levels required to reach that power goal. Usually the size of the turbo dictates how much actual PSI you can push into a given engine. You can't just put a gt35r on, and expect to run 35 psi from the turbo. It will stop making more power somewhere around 20 psi, the heat generated will exceed any increases in oxygen from the higher boost. The to4z is an excellent 400-500 hp turbo, with everything else being equal you will probably find similar power levels at 1 bar compared to say a gt35r, but as you go up in boost, the to4z would make more power due to the higher efficiency at higher boost levels.

turbotoaster

sorry for jumping into this little arguement ernie but after the post you wrote could i ask a question.

you say you have messed with the 3 types of mixes with AI which did you find best for high boost, i know water holds off det and helps a bit with air temps but you mention meth drops temps alot more, does this cause more power at same boost but doesnt allow you to increase the boost as high as straight water as it will det at an earlier number.
thanks in advance