jreynish

iTrader: (2)

well the,,, that proves that!
Weird, have you spoken to BNR yet?
if so did he give you any sort of explination?

edomund

Rpeck bryan said "That turbo doesn't make the airflow down low that the stock one does, so right off it will be lazy on the bottom b/c of being too rich."

He said some other stuff but it only aplies to me.

You should email him and tell him exactly what is happening and all your mods. He will probably be able to help you.

Can you send me those numbers for s-afc hi and lo your pm isn't working anymore.

adamlewis

After seeing all these people with BNR problems, Im kinda glad I didnt go that route...

Rpeck

Thanks for the info, I am pretty sure I e-mailed him with this info many many months ago, when I first finished the build, i will double check, or mail him again to be sure. Sorry about the PM's I will send you those #'s first thing tommorow.

Edit; If it's just a matter of being to rich down low I can adjust that ... but the dyno said my A/F ratio's were right where they needed to be ..

-Robert

Maxthe7man

On the stock turbine, mixtures wouldn't affect as much as that...
You say you don't have a massive exhaust leak, so if I take your word for that, then thats not it, then I would have to say that the clip on the turbine is a disaster, and there is not enough blade left on it to spin the upsized compressor until higher rpm's...
The turbo is a pretty simple device, gases in gases out... IF you have no intake leaks no exhaust leaks, and the shaft spins freely, then the turbine clip is causing your problems...Max

edomund

You should email him again he always responds to my emails quickly. He has always had great customer service. If you narrow it down to the turbo he will replace it. But I bet there is another problem.

adamlewis Rpeck is the only one with a real problem with his BNR hybrid.
I just dont have mine tuned or exhaust yet and I get boost around 2500-3000.

I was just wondering what others had experienced.

adamlewis

Ah well.
I already went the full T04B route.

jreynish

iTrader: (2)

at this stage I would have to agree with Max, if you have eliminated;
a) no exhaust leak
b) WG working properly
c) A/F mixtures proper (all thaught i don't think they could affect it THAT MUCH)
d) no intake leaks

then i would have to agree that there may accually be a problem with the turbo. Talk To BNR and find out what he says and or is prepared to do.
Good Luck

BLUE TII

iTrader: (9)

I did the RB large templates on both my intake and exhaust

THIS MAY BE PART OF YOUR PROBLEM

I don't know for sure what the "large" RB exhaust template you used for poting was but here is what RB says about their exhaust race porting service.

Race Exhaust Porting is a modification performed only on a new rotor housing. This modification involves changing the profile at the internal end of the port, and blending that profile into the port outlet. Race Exhaust Porting is only appropriate for engines with bridge or peripheral porting. Either Blocking Nozzles (for 1975 and earlier housings - see Engine section) or Air Injection Hole Plugging (for 1976 and later housings - see Engine-Services section) is recommended, but not included.

Sounds like you might just have to rev it up to 10,000+ rpm so the affect of increased overlap is minimal- oh, maybe more rpm since you have much higher exhaust outlet backpressure making the affects of overlap much more pronounced in your turbo application.

BTW, I really hope this isn't the problem! That would suck ***** Total rebuild of engine and buying rotor housings (maybe trade a bridgport/P-port NA guy?)...

Just from fingering Rob's Pineapple Stage 2 streetport he recommended to me for quick spool it looks like he just brought the top (more overlap) up ~2mm to match the size of the exhaust sleeve and brought the bottom (earlier opening) down a LOT more!

This is consistant w/ general exhaust porting process for turbo no emmisions street applications from what I have read.

BLUE TII

iTrader: (9)

That last post was for Rpeck, not original thread starter.

Sorry

jreynish

iTrader: (2)

BLUE TII;
Is that due to the fact that there is more backpressure making the port too big? I would like to fully understand the reasoning for this?
Is it because the turbo provides such significant back pressure that the port accually provides turbulance?

BLUE TII

iTrader: (9)

Yes, the vastly increased backpressure between the turbo and engine causes overlap between the exhaust and intake ports to have a enhanced DETRIMENT during turbo spool up as the exhaust pressure is much higher than the intake air pressure.

In an NA there is very little exhaust backpressure on a well set-up bridge or P-port (typically they run turbo exhaust sizes w/ out the backpressure of a turbo). Not to mention they aren't expecting good low end anyways. A bridge or P-port NA would probably love to have Rpecks laggy powerband, vast improvement over their own- except Rpecks computer, oil system and internals, etc do not look up to the task of the RPMs needed take advantage of the overlap.

In a pure race turbo set-up the overlap should be much higher since spool up is not as important (and can be fixed w/ proper exhaust manifold, anitlag etc.) so large overlap is used so that once spooled the high boost intake pressure is greatly enhancing the BENIFITS of overlap as the intake boost is literally evacuating the lower pressure exhaust from the engine and its low backpressure huge turbo.

W/ porting for overlap it is all about the pressure diferentials.

Rpeck

Here is a pic of my exhaust porting, as I did it... I don't think it's abnormally large;

POS damn server, i hope they didn't pay for this "upgrade" I will attach the pic if /when it will let me

I had to put it in my photo album, here is the pic

My Exhaust Port

I also pulled my reciept, my port template parts #'s are

Exhaust 22215
Intake 22202

jreynish

iTrader: (2)

that doesn't seem to be much larger than mine is! So i dont' think that will be it either!
Werd!
Personally I still think that it might be your turbo!
Have you talked to BNR yet?

Rpeck

No I am yet to talk to him, He clearly states in all the warranty paperwork that it is warrantied for 1 year. Well i purchased it on 7/2/02 ... However I did not install it until months later, I was still in the process of the rebuild.

Also i want to write a fully detailed e-mail explaining everything I have done, tried and tested... with dyno sheets to back it all up. That way I can give him the most info to work with. But I have just been to damn busy with other things to write up the 6 month long story of "Rpeck"'s turbo woes You can't imagine what all I have gone through, and tried to correct this.


And to tell you the truth I really do not think there is anything he can suggest that has not already been sugested, tested or tried. Myself and the mebers of this forum are I am sure more educated in the working of a turbo rotary then he is. He is a Turbo guru for sure... Infact he did the one thing on my car i could not do myself (the turbo rebuild) But what can he possibly suggest that I have not yet tried?

-Robert

Rpeck

My digital camera is capable of vidoe recordings also, i think tommorow I will set it up in the cockpit pointed at the boost gauge, and tach .. You should be able to tell the gear by the MPH. That way you guys can see by video how it is acting, and tell me what you think.

One more thing I was thinking about doing; I have a local torbo shop in town (they do almost exclusively deisel truck turbo's) but I was going to order a turbine wheel without the clip, and ask them to install it. Am I wasting more money? or is this a viable attempt at a solution? is anyone else running a stage 3 BNR with a 15 Deg. clip? ......

jreynish

iTrader: (2)

before you have them oder and install a new clip I would definitely see what BNR has to say! maybe the clip was screwed or heaven forbid that he accidently clipped the wrong wheel making it totally useless! These are only a few of many possibilities but i would definitely check with him before spending any more money!

BLUE TII

iTrader: (9)

I seriously doubt it is the turbo. A turbo by itself is a very simple device.

I can't imagine how you grind a stock wheel so much it wouldn't boost creep pushing that 60-1 compressor.

Rpeck, your port doesn't look overly large to me (not that I know much about porting), but the angle of that shot does not show off the upper end (overlap) of the port well.

Perhaps your laggy boost is a combination of things? Restrictive stock IC, TB and manifolds trying to flow over twice the CFM they were designed for, AFM restricting flow (I know TID mod does wonders for spool-up, I imagine ditching AFM does as well), more exhaust overlap than optimal and maybe even more thigns.

One more thing I was thinking about doing; I have a local torbo shop in town (they do almost exclusively deisel truck turbo's) but I was going to order a turbine wheel without the clip, and ask them to install it. Am I wasting more money? or is this a viable attempt at a solution? is anyone else running a stage 3 BNR with a 15 Deg. clip? ......

I believe the exhaust wheel and shaft are a unit. You are thinking of buying a new HT-18 exhaust wheel and having a shop rebuild and balance the turbo w/ that? I think that is a big waste of money.

There is at least one other BNR stage 3 owner w/ 15 deg clip that I know of. Reading his posts gave me the idea for dividing the exhaust and wastegate flow and open air venting out the back plate. It worked for him to keep his insane boost down, not enough for me. I will search for you...

BLUE TII

iTrader: (9)

Here is Dcee's post on boost creep w/ his BNR. Not sure of its exact specs, but this is what inspired me to try external venting the stock WG.

https://www.rx7club.com/showthread.p...p&pagenumber=1

Rpeck

I feel the same way, that's the main reason I think it is out of Bryan's hands. I will have a FMIC setup by Nov. 11th I just don't know whats next after that. I wish I had such a boost creep problem that I needed a external gate and divided exhaust i would certainly MUCH rather have a problem of too much boost, i would not mind at all throwing money at that. It's such a 'small' turbo ... in comparison to many other people setup's that I just can't see my intake, or TB or even the AFM being an issue. The insane lag just does not read 'intake' to me. I have done some trial runs with my air cleaner off the AFM, and no change ..

Rpeck

BLUE, how does your car act at say 3000 RPM's and you stomp the gas? do you just hit boost? My car is just a dog, slower then an N/A then climb, climb, climb RPM's at 5,500 it takes off like a bat out of hell. I have never owned, nor even drove in a stock TII ... so I am not sure what the typical reaction should be, so I am also curiuos hows yours reacts with your mods.

BLUE TII

iTrader: (9)

Cruising at 3,000rpm the boost response is pretty good. If I floor it fast the boost guage jumps to 0 manifold pressure and then hesitates for for a fraction of a second and then builds boost fast enough that it is at max boost (17psi) by 3,500rpm. If I ease on the gas at 3,000rpm for 1/2 second and then floor it the boost response is seamless and a little faster.

Power comes on hard w/ full boost at 3,500rpm, but at 5,000 rpm there is another surge in power. The 5,000rpm surge gets the "holy crap" comments from passengers as they can't imagine another big surge in power just after they felt the car surge at 3,500rpm. The 5,000 rpm surge is also the one that breaks the tires loose in 3rd gear.

Cruising at 3,500rpm the boost response is just downright twitchy. Instant boost/ acceleration w/ light pressure on the pedal- full boost nearly as fast as it takes to get the pedal to the floor.

Rpeck

Damnit! That's what I want
I guess I will keep pluging away, see if the FMIC improves anything ... I will need it sooner or later, one way or the other I figure.

jreynish

iTrader: (2)

Good Luck and let us know what the end result was!

BLUE TII

iTrader: (9)

Here is a snidbit from a report on the Garret Aviation VNT 25 turbo that explains what I have been trying to say about too restrictive an IC and intake manifold really slowing boost response.

2 ¼ inch inside diameter round pipe fitting. This fluted shape insures that the speed of the compressed charge is kept relatively high. The high speed maintains that the compressed charge is kept away from the compressor. If it were allowed to back up near the compressor, the compressor would have to work much harder to move the already dense air. The result would be that the clready compressed air would be further compressed and heated. Although the small inlet and outlet sizes contribute to increased velocity With the introduction of the Garret

So, you see that going from the 2" 60-1 HiFi turbo outlet into a 1 3/4" 6" long pipe to a 1 3/4" IC inlet 90 degrees to the IC core into a very small end tank should REALLY slow the spool-up as you are slowing the air considerably as it exits the compressor and backing compressed air into the compressor blade.

In an well designed system the diameter/volume of the piping is gradually and constantly increasing.
Mine is 2" turbo outlet 2 1/4" pipe to 2 1/2" IC inlet to a 2 3/4" turbo outlet to a short 2 3/4" pipe to the Greddy elbow which is 2 3/4" and expands gradually to TB size.

As few bends and length as possible is also ideal as the friction will slow the intake flowing through.
Mine has 1 90 deg bend and one 15 deg bend in the whole system and 24" of piping total.

If you want tips for freeing up the TB and intake manifolds- let me know.