BLUE TII

iTrader: (9)

Edit-if it still creeps after that youve got another problem i think. maybe, i dunno, are you getting the same readings on boost pressure off your haltech as you are off of a normal analog boost gauge? maybe your boost gauge or MAP sensor is messed up and giveing you a bogus reading?

Oh, yeah the boost is for real. The Greddy guage, Haltech and Pop-off valve all agree. Power level agrees too. We are talking about 3rd gear losing traction when it hits ~6,000rpm (225/50 180 treadwear tires on 8" rim).

Paul Ko (K2RD) estimated 400RWHP based on my traction issues. My goal is 300RWHP- anything more is icing on the cake; I think I might just have a little icing

Turblown

iTrader: (12)

Let me get something straight here; 400rwhp on a hybrid?

Maxthe7man

I don't think thats gonna happen on a hybrid to much back pressure, and I think thats the whole problem with this setup, there is just to much exhaust moving or trying to through that turbine setup, *if everything else checks out*.....
I modified Rx_7turbo's hybrid for external gate, but I welded onto the manifod instead, as I far as I know its creep free(the only creep being the one driving it.. )and thats with a 35mm tial on it...

Turblown

iTrader: (12)

bump..

rx7_turbo2

Hey I'm no creep

I have a hybrid and to be honest with you I should have done it right the first time. Using the stock turbo the exhuast side is a bottle neck, so why throw on a MUCH larger compressor? The exhuast side is adequate at best with the stock turbo, now your trying to push significantly more exhuast volume through it.

Not an attack BLUE TII but with all the money you've spent why not go with a "real" turbo setup?

BLUE TII

iTrader: (9)

Pic request from this thread-

BLUE TII

iTrader: (9)

...

RotaryEvolution

iTrader: (30)

seems like alot of work to retain the stock hybrid turbo..

BLUE TII

iTrader: (9)

seems like alot of work to retain the stock hybrid turbo..

Yes, it happened in stages trying to fight boost creep.

If I were to choose a turbo now I would try something simple like divided T3 FD cast manifold and 1:00ish T3 exhaust housing with the same "P" trim exhaust wheel and 60-1 compressor I am running.

Though I am sure I would have to port the passages for the external WG on T3 FD manifold as well.

OR

Just do a S5 hybrid turbo and restrict the exhaust to eliminate boost creep and be happy with ~300rwhp and a cheap, simple responsive turbo.

dwb87

iTrader: (22)

I really like your set-up... What kind of response have you seen with the horizontal/V-mount and the BNR stage 4??

dennis blackstone

any one have a diagram for the vac lines for the turbo
or pic of the size of your lines

gxl90rx7

iTrader: (1)

i have had a lot of luck with my s5 hybrid just by taking material off of the backside of the wg door and out of the backplate where it hits. I am running a 60-1 hifi compressor. even without porting the passages at all, with a stock unclipped turbine wheel, and it only creeps to 10psi. i also have an unclipped p-trim version, and it will hold steady at 10psi too. check out how much further the flap can open



im working on getting a bellmouth downpipe made that replaces teh backplate. if this works like i think it will, it would be bolt-up, not mods needed to the turbo at all to prevent creep

BLUE TII

iTrader: (9)

i also have an unclipped p-trim version, and it will hold steady at 10psi too.

The creep will depend on how open your intake and exhaust is.

My set up has low restriction intake and 3 1/2" exhaust. When I put the restrictive Racing Beat RevTII 3" turbo back on it didn't have boost creep issues.

This happened in steps as this old long thread shows and one step was cutting a hole in the backplate that the flapper opened up into and the exhaust went out of separately.

I have ported wastegates and flattened out the flapper arm as you have shown on another stock S5 turbo and it does help fight boost creep.

BLUE TII

iTrader: (9)

I really like your set-up... What kind of response have you seen with the horizontal/V-mount and the BNR stage 4??

It gets 2-3psi boost by 2,000rpm to ~8psi boost by 2,500rpm and ~10psi by 3,000rpm and full boost (~14psi) at just before 3,500rpm.

Boost response is not 3rd gen sequential twins super snappy anymore like it was before I ported the manifold and turbine runners huge and finally eliminated the boost creep.

Still the boost response is very fast above 4,000rpm so that it does make it hard to auto-x in that range in 1st or 2nd gear. Some courses it is fastest to lug it around in 3rd making it easier to modulate the throttle.

On the hillclimb and especially the kart track I have raced on the powerband suits the gearing quite well and I don't feel like I am waiting for the turbo, rather waiting to squeeze on the gas to keep the lines clean.

BLUE TII

iTrader: (9)

any one have a diagram for the vac lines for the turbo
or pic of the size of your lines

gxl90rx7

iTrader: (1)

yes i running the older RB 3" exhaust, so maybe that is keeping creep down

interesting.. goes to show runner diameter is more important that most give it credit. i htink that is why the stock manifold spools so well.. small diameter runners

BLUE TII

iTrader: (9)

Yes, the stock S5 manifold is designed for very high velocity into the turbo as it incorporates a sharp reduction in volume right out of the motor in she shape of velocity stacks.

Unfortunately, this is also part of the cause of boost creep issues as the exhaust has such high velocity in the turbo runners it takes a lot of persuasion to get it to turn into the wastegate runners.

lim_fc3c

iTrader: (4)

Im pretty much doing that same thing modification wise with a T04b Vtrim bnr stage 2 clone. I will be running a nearly open 3" stainless exhaust system. I cut open the back plate for external venting and did a little porting in the passages while keeping the stock flapper. Im using a AGP wastegate actuator with a 9psi spring. I hope it will not creep much since my goal is only 250whp with the stock TMIC, megasquirt, and stock ports.

Any thoughts?

BLUE TII

iTrader: (9)

I hope it will not creep much since my goal is only 250whp with the stock TMIC, megasquirt, and stock ports.

Any thoughts?

I don't think you will have the same issues with boost creep due to the smaller V trim compressor.

The BNR Stage2 or similar hybrid seems like a more balanced approach that allows you to keep things simple.

AGreen

iTrader: (11)

I don't know if your turbo is much different from mine, but I also run a 3" exhaust, TO4B v-trim hybrid (60A/R cover, S5 manifold and turbine housing) 3" intake w/ K&N cone filter, and a MS2 v3 ECU. I have stock 550cc primaries and 720cc secondaries. The ONLY difference is that I have a V-Mounted intercooler, vs the stock TMIC. I had very little issue with boost creep. I did eventually do like gxl90 did, and ground away some of the back plate and some of the flapper so any boost creep that I did have is now gone.

With the stock S4 turbo on it (completely stock, except for the 3" exhaust) it crept WAAAY high. I won't even discuss how far up the boost got on it... it was high.

SirCygnus

iTrader: (1)

i have such a huge problem with boost creep, that i just let the turbo scramble boost because the waste gate simply cant control it.

rxse7en

Unfortunately, I have a pretty strong engine with a stage 2 street port and I'm currently trying to tune a BNR Stage 1 on the dyno. We've had to shut it down at 5000 rpm every time as the boost was spiking to 15+ pounds. I have a dyno run of the Stage 1 making 280rwhp at 5000rpm and 15 pounds of boost. My intake and exhaust have no restrictions. We tried wiring the waste gate open (the flapper hits the rear plate at 30º) and we still spiked to 14 pounds at 5500 rpm. In my case, I don't think I can clear enough out of the back plate to make this work. Fantastic turbo, I've just outgrown it too quickly.

Furb

iTrader: (2)

A stage 1 is basically a stock turbo, just a bigger compressor.
Not a big surprise you outflow the turbo with a streetport

BLUE TII

iTrader: (9)

When the motor outflows the compressor the boost will drop on the top end.

He is having the problem of over speeding the turbo shaft and therefor the compressor from having way more exhaust energy driving the exhaust wheel than what is needed to maintain target rpm (boost).