YearsOfDecay

We'll I previously posted a writeup on my BNR StageIII after its initila track day.

At that time I was having some boosting issues, couldn't get more than 12 PSI in second and barely 14 in Third, even with the profec "B" high boost set all the way to max.

After talking with Bryan about this quirk, he suggested that my Greddy Profec B might not be able to bleed off enough boost pressure quick enough to stop the wastegate from opening to early, thus, the laggy boost. Also, once it opens, the 5 PSI spring in it isn't strong enough to pull it completely closed again once the exhaust has started through it, thus the lack of boost.

He suggest a restrictor, such as a carberator jet, in the out line from the profec B soleniod.

Makes sense, theoretically, a small hole will allow the pressure to equalize quickly, but will not allow a large volume of air through at any given time, thus, creating backpressure on the solenoid and allowing it a bit of time to bleed off the boost pressure pefore it goes to the wastegate.

Well, being that I sold the RD350, and have no carberated junk laying around... I went in search for a suitable replacement. I found it... a .030 Mig Welder tip!!!!! It fits PERFECTLY inside the 6mm Vac line that goes from the profec B solenoid to the wastegate. I simply cut the threaded portion off, stuck it in the end of the Vac line and then put the vac line on the solenoid again. I then zip tied the solenoid connection and then zip tied the "pill" in place so it wont travel down the line in case i ever want to take it out. I used the threaded end of the welding tip for this reason, so that it would grip to the tube when i zip tied it.

OK... Road Trial.... the FIRST thing i did was turn the high boost down to the same level as the low boost as bryan suggested. I then put the car in second gear and mashed it at 3500. the car hit 10 psi about a split second after i mashed the gas, threw me into the seat and started frying the tires at 4500... DEFINATE IMPROVEMENT.

NEXT, I turned the high boost up a little.. 2rd gear 3500, mash it.... 12 PSI, thrown back in the seat, tires up in smoke... Now were getting somewhere...

Turn it up a bit more... 3rd gear this time.. 3500 Mash it.. BLAMMO 14 PSI, tires spinning a little, but i stayed in it, and it kept 14 psi to 6750 when the "oh ****" lite comes one!!

What the hell, the Haltech is set to 14 PSI, but i have it richened up there after... turn the know a bit more... 3rd gear, 4K mash it, 16 PSI, tires lost it ....and I almost lost my cargo into my shorts!!!!!

I need wider wheels and a hell of a lot stickier tires (the ones that are on it came with the car, and they are almost brand new so i'm trying to burn them off rather than toss them ... they are Kelley chargers and i think they are made of recycle PEN erasers... you know, the hard ones that really don't erase ****, they just wear the paper away!!)

SOoooo The moral of the story... the LAG with the BNR stageIII (s4 with ported housing) is MINIMAL.. The thing spools like a rocket. This BNR iwas well worth the money!!

I need to retune for Higher boost, and fix a fuel pulsation problem (parts are on the way) then Its off to Wagner Motorsports here in York to have this sucker Dynoed!!!!! I suspect However, Thats its going to be over the 350HP i was shooting for when i started this project.

RotaryRevn

Are you still runnning the twin scroll flapper on that s4 turbo, or did you remove it and plug the hole?


I have both a series 4 and series 5 turbo lying around and not sure which one to get highflowed. I have heard the series 5 will spool quicker, but the series 4 will flow more because the manifold is less restrictive? I have also heard that the seres 4 wastegate can be ported to work better than the series 5. Any thoughts on this?

thanks

hondahater

iTrader: (2)

you bastard! I want a stage III now but have to wait a long while for the funding! Good job man sounds like what I'm going to have to do with my profect b if I ever get a stage III. would this help with smaller turbos. I think I got a to4b hybrid or is this only for a stage III?

YearsOfDecay

I have the S4 manifold with the twin scroll removed and a bolt cut down and welded into the hole. Bryan said that you can flow a hell of a lot of exhaust through the s4 manifold and he modifies the turbo inlet as well.

Bryan seems to like the S4 turbos cause he can port the hell out intake runners he also ports the wastegate and puts a 35mm flapped on it.

I don't know what he does with the S5 wastegates, but, i know the do it yourself method of porting give better results with the s5 being that there are two holes instead of one to enlarge. However, with the uprgraded system, i'd think he would replaced the flapper entirely.


Email Bryan at Bnrsupercars@aol.com or call him at 205-640-1193. He'll gladly give you the rundown on the ups and downs of each.

YearsOfDecay

It will help with any high output turbo that is still using the stock wastegate actuator. The problem is in the weak assed 5lb spring in the actuator, I don't think its the Profec's fault either cause it probably wasn't designed with a 5lb spring in mind!!!

A Stage III IS a TO4b Hybrid my man, its just a really worked TO4B Hybrid with a 60-1 compressor wheel and some other goodies.

Some hybrids use the stock compressor cover with a TO4 Wheel machined to fit inside it, is that what you got?? cause thats like a BNR Stage1. The stage III uses a complete TO4 cover and modified 60-1 wheel.


Also... I don't know if the Profec B "Spec II" needs this mod or not, I didn't like the look of its solenoid box, so I went with the oldschool Profec B. Maybe the "Spec II" won't need a restrictor pill in the line. Anybody got one???

The description of the Stage III on RX-7store.net says its capable of 350RWHP... that must be on a stock motor and ecu cause I think I'm pullin a bit more than that with my ported motor, FMIC and Haltech..... (at least my car has already taken cars that have dynoed at 350+) but dyno tests will have to prove that.

hondahater

iTrader: (2)

OK I'm going to try something like this out then to see if it helps. I think I have like a stage II or something because it hase a to4b vtrim witch it is supposed to make around 320 hp witch may hold me over for a while. Anyways thanks for the help. Mine is the old school profec b

RotaryRevn

Thanks for all of that info

wozzoom

OK, I'm super interested in this find... A buddy has a similar problem with his 90 TII.

Current setup:
Street Ported S5
BNR Stage 2 (S5 manifold and turbo)
Microtech and Profec B controlling it

Symptoms:
Car takes forever to spool! Full boost doesn't hit until about 4000 RPM at which point he's seeing 14 lbs. On hot days, on the top end at 6500-7000 boost would bleed down to 12 PSI.

You're saying to put the restrictor pill in the line that goes from the solenoid to the wastegate?

J-Rat

iTrader: (2)

there is Definately something wrong there.. I have a stage 4 on a stock port motor, and I can spool that turbo at around 3-3500.

$150FC

man i got to get my car running

dr.jones63

Your killing me. I still need to wield the BOV to the new Greedy piping and Set up the Microtech to get my BNR stage 3 on the road.

RETed

It's funny reading this when people are bitching about back pressure and how it kills your engine prematurely...


-Ted

Gimpie7

word

Gimpie7

By the way it's Gibbsie^

Rex4Life

Yea I saw that over in the turbo section--I don't buy into that theory at all. If that was true everyone with a stock exhaust would be killing their engine.

YearsOfDecay

Dude.. try it... got to home depot or lowes, buy a .030 mig welder tip, cut it in half and stick the half with the threads on it in the tube that goes from the solenoid to the wastegate then slide the tube back on and zip tie the pill inside the tube as it sits against the metal nipple on the profec (I put it in the tube so that it was flush with the end of the tube, then pushed the tupe over the nipple on the profec solenoid.. get it???? Whe your finished, you have the pill sitting right on top of hte profec nipple.)

nonameo

Well, the only problem I see with that theory is that with a hybrid you are moving more air into the engine, and therefore have to move more air out. But the restriction remains the same. Thus, more backpressure.

YearsOfDecay

Yeah, i was following that thread myself... there is no way on gods green earth that the my BNR is putting more backpressure on my motor than the stock turbo and cats were.

However, I'm a realist.. I've hopped up my motor to twice its design HP capacity, if that follows the inverse square rule... i'll be happy if the motor gets 1/4 of its stock life expectancy anyway..

Back pressure eating up motors....... HEY ROCKET SCIENTISTS..... you start sqeezing 500HP out of a 1.3 liter engine oroginally designed to make around 200 hp..... you aint gonna get 100K miles out of it!!!!!

Hell, 30K would be nice.. thats like 8 years now that i can only drive it 5k per year!!!

nonameo

Well, clipping changes things. yours is clipped.

edit: doh! that's what wastegates are for... to relieve backpressure. my apologies.

wozzoom

We'll give it a try. I'll post the results. Thanks for the ".030 Tip"

Triangle Power

Alright, Wozzoom and I tried this on my car last night. This is a Microteched, fmic, BNR Stage II car. I had similar problems to YearsOfDecay. After putting the restriction in I was able to crank the profec back down to about 40% of max on the high map (previously set on max) and still hit 15lbs at 4k rpms. The boost seems a little smoother now but isn't coming on that much faster. I'm not smoking tires or anything. There was no dramatic change. Before trying this the car did dyno 328rwhp. I don't sense any big power gain.

Upper rpm boost seems to be a bit more stable but I still experienced a bleed off after 6k rpms. I am getting hesitations at the top end now from too much fuel. I'm guessing the change in boost response is fairly different from when the car was tuned a couple months ago. The only other thing I can do is upgrade the DP and silencer to the 3 inch. I currently have 2.5inch setup. Any thoughts?

RETed

If the maps are too rich, this will suppress power.
You got a wide-band by any chance?
Retune the Microtech.


-Ted

RotaryRevn

Allthough retuning the microtech will help with the running too rich at higher rpm problem, the real problem is the boost dropping off at the end and causing the car to run rich right? So your trying to figure out what you can do to get boost to redline. Please keep us updated as I'm also thinking of going with the BNR set up but all the problems scare me.

328 rwhp sounds awfully good for a stage 2 . Should be plenty for my first gen. What size injectors are you using? When does you turbo start producing boost?

Triangle Power

RETed: Nope, didn't buy the wideband option for the Microtech yet. I know too much fuel will cut into power output. The maps were set perfectly prior to installing the restriction. Now that the restriction is there I'm getting the overly rich hesitations up top. Must've made a decent change. I won't get a chance for a retune until after winter and after I upgrade the exhaust. I'm hoping that's it, that the piping is causing enough backpressure to be restricting my boost.

RotaryRevn: I made 304rwhp at 10lbs boost on KDR's dynojet on a humid day, probably about 80 degrees. We cranked the boost up to 15lbs which bled off and only made 310rwhp. I then ran it again 3 days later in Ocean City Marlyand (right at sea level), outside on a less humid, 82 degree day and made 328rwhp on another dynojet (15lbs bleeding off). I'm running 4x 720cc injectors but I'm starting to get close to thier safety zone. I think I was running around 89% duty cycles. I start seeing boost as low as 2200rpms and have full at about 4k-4200rpms.

It's rather frustrating. I had boost the bled off with my stock turbo, stock intercooler. So I buy all this stuff , make a ton more power but still have boost that will not hold until redline.

Triangle Power

If you get a stage 2 in a 1st gen you'll never stop smiling. I couldn't even imagine what that would feel like