it's a 1.06 a/r hot side, T3. I remember talking to a vendor about long manifold vs short and short allows the use of an air pump but it limits the size of the turbo and one sacrifices in boost threshold.

Actually my tuner/mechanic loves my single. he says it's one of the fastest spooling ones that he's tuned yet.

 

Go sequential if you are running twins.

Otherwise, you are just simulating a larger single... with a less efficient manifold, more heat soaked material in the engine bay, and over all less efficient intake tract due to the joining of two airstreams.

Non sequential twins is like saying.. hey... I want a single turbo that is much less efficient.

 

go single....

look how many people went bnr and are now looking to or are running a single. thats the best indication in itself. \

in my opinion the bnrs are good if u need to pass smog i guess. i dont see the value in spending all that money to make 20 rwhp (in sequential mode). and that is as real as it gets.

now going single u have tons of options and power levels to choose from. as well as being more simplistic.

if u like twins then keep the stockers 350-380 is piece of cake.

if u want 400 plus go single.

 

someone explain to me what exactly the bnrs offer. i have been reading about them for 3 yrs and still dont understand.

 

They are a different chra inside the stock manifold and housings. they offer higher boost threshold, 360 degree thrust bearings instead of 270 degree. They allow for higher boost, more power, slightly better efficiency than stock, ans apparently more reliability than stock. Larger center shaft too. Also, they are custom gt28 chras instead of the Hitachi HT12's.

There is more, but that's the basics of it.

The BNR's are much more able to be ran at high boost than the stock turbos. Plus, you can get them in sequential. Plus, you can run higher boost. If you want sequential twins, the BNR's are the way to go. Simple as that. If you want higher horsepower and don't mind lag, single is the way to go.

I ended up going with the gt3574r single over the bnr's... but I may come to regret that decision when autocross season rolls around... I may not though. we will see.

 

yes i know that. still means nothing to me.

and i disagree with you. if u want sequential twins stay with the stockers. but to each their own.

i am talking actual dyno numbers. from what i am seeing they offer 10-20rwhp as you can run 17psi with them vs the stockers at 15 - 16psi. thats it. thats the ball game as far as i am concerned. is 20 rwhp worth 2500? thats the question one needs to ask himself when faced with this decesion. thats the nuts and bolts of the question.

another question is, will i be bored of the extra 20 ponnies in 6 months......

 

It's more then 20 rwhp. If you compare cars on the SAME dyno you will see what I mean. 15-16 PSi on stock twins, and you need new turbos every few months and depending on your usage possibly more often. 20 PSi on BNR's and you don't have to think about it.

With a properly setup car, BNR twins @ 17 PSi, can be equal to a GT35R (T4 0.82 A/R) @ 14 PSi. I know because I've done it and I tuned both cars myself. And if I had kept my BNR's and added methanol. I could foresee great improvements since that would take away A LOT of heat.

thewird

 

u guys are probably right. my experience is unique to my car only. i am just going off of what i read, which is 360-400rwhp of actual dyno results. which is pretty similar to the dynos i have seen of the stock setup with the mean of call it 350 vs 375.

but i disagree with the 15-16psi on stockers. oh well. who cares anyways.

 

Guys, BNRs are twin T28s, a full 20% larger than stock. Simple physics says they'll outperform stock twins.

BNRs have larger turbine wheels than stock so run non-seq they'll be laggier than stock twins non-seq. Run them sequential and you can make 400 rwhp all day every day, with quick spool and a great powerband.

If I had been running my BNRs seq I'd probably still have them installed. Brian makes a fantastic product for the price and ease of install.

Run stock twins and you can make 350 rwhp all day every day. Much more than that and they'll fry sooner rather than later.

 

Hey Rich,

at what RPMs did you reach 10 psi with your BNR's?

I was on fence as well BNR's vs single. After speaking to Brian I had decided to go BNR's sequentially. But at the last minute I got a good deal on my single so I went with it.

 

I already mentioned that they were t28s (I mis-stated and said they were gt28s)

This guy is hell bent on saying they are not better than stock. He is not going to listen.

It doesn't matter that the turbo itself is designed to last longer at higher boost levels. It doesn't matter that the turbo is bigger. It doesn't matter that a set of BNR's is still cheaper than 99 spec twins. But hey... he wants to say that he can get the same performance out of BNR's with his stock twins. I doubt that I would EVER need more than 400 hp on an autocross course.... especially sequentially.

 

This has become a pretty good thread, and i have made up my mind about 3 different times now im leaning back toward the GT35 kit. Whats the significant differance between the GT35R and the GT3574? From what i can tell the 3574R has quicker response but less top end power... but im probably wrong.

 

Is your budget $2500 or $5000+?

 

autocross courses are rather small and VERY technical.... a single does not do well here, even if its a rather small one for our motors.

most of the AutoX events i've been to stock twins and BNR FD's do VERY WELL against top contenders like Miata's, Evos and surprisingly even Mini's. Single FD's on an AutoX course are epic fail.

sure, they make some very sweet noises, and they make good top-end power.... but the real winners have power in the low end part of their power band, and excellent suspension setup.

 

ding ding ding

thewird

 

My price range.... hmmmm well let me see... Obviously i dont want to spend 5K id rather spend around 3,500 max. I think thats about what the T4 kit goes for.... IDK!!! Looking in to autox some more i dont know that its so much for me..... Maybe way down the road when i have more time and im a better driver... I think im just going to take this car out to the drag strip and maybe **** off a few vette or mustang owners on the highway for a little while, make it a fun weekend sunny day spirited driver kinda deal.... Im starting to like the simplicity of a single alot.

 

Drag strip = big single turbo ^_^

You have to remember the cost of single turbo isn't just the turbo kit. You have to completely upgrade your fuel system with rails, injectors, lines, pressure regulator etc. There are other things which aren't coming to me right now as well. And don't forget the other stuff like radiator, intercooler, oil coolers, ignition amp, blow off valve, etc etc.

thewird

 

I have already take all that into consideration im getting ready to order... Denso pump, extreme fuel kit, pettit coolcharge III, greddy elbow w/ flange, rs bov, the boost control kit for the Power fc or the AVCR (still undecided) and either Aquamist or cooling mist kit. My engine is probably close to death right now (i have no real reason to say this it runs great, idles smooth, pulls strong but has 87K) but even tho it seems surprising I recieved an extended warranty on the rx7 when i got it. 3 years 36K on power train but its only good for up to $3K in parts... So i dont have to worry about shelling out a **** ton on the engine... And i have already had it checked out with the local dealership Hall mazda in Va and its a good warranty.

 

3500 isnt enough to go single and in general a 35R won't do well on an autox course unless it's something like a t3 0.84 hot side A/R.

 

3500 would be for the kit not for everything else involved i already have funding set aside for the majority of the stuff listed in my last post... Just saving for the coolcharge III intercooler.

 

Buy the setup that suites your purpose.
Want to reign supreme on the autoX course - BNR's..perhaps. However, extra power is nothing without tire and suspension it just gets you out of the gate quicker
Want to go drag racing - Monster T78 or new HKS turbos the same size as a rotor housing.
Want to go road racing - GT35R or similarly sized turbo.
Want to be a street king from a roll...
Want to be a dyno queen with nothing below 7000rpm...
So what's your need? Choose wisely.

Regards,
Crispy
...GT35R for the record

 

Why don't you do yourself a favor and try to find some dyno plots of the options youre considering and make your decision based on hard data vs personal opinions and nonsense?

 

lol good post Chrispy.... Street king sounds about right for the next couple years

 

well then def go single

 

what about the T51R