Ok....well, I blew my stock twins about 2 months ago....prior to the blowing, they pulled really good, felt fast (for twins), and had decent Butt Dyno Proven Power.

Now since they blew, I had to replace them....but I wasn't ready for a single...lack of fuel mods, EMS, and money...so I went with some BNR Stage 2 Twins. I also switched from running a M2 Large SMIC to a Greddy 2 Row FMIC and switched from K&N Intakes to the Greddy Airnix Intake Kit, but everything else is the same. Still running non-sequential, still running 10psi, still using the same Boost controller, etc...I did remove the flapper from my manifold though as opposed to having it wired open via the poorman's version.

But now my car feels alot slower at 10psi....it makes **** for power between shifts, barely chirps the tires in 2nd now...where it used to blow them off in 2nd...it also lags like all hell. It doesn't feel real bad while passing...but since I can't compare side by side, I don't know if it feels slower then or not....but when I am trying to bang gears or just accelerate in 1st, 2nd, or 3rd....it feels alot slower.

Now, do the BNR Twins just not do as good at 10psi....I know they are supposed to be capable of 17-18psi but I am not...so they have to run 10psi like stock. I just assumed they would still pull as good as my old wore out 82,xxx mile twins...if not, just a little better.

Can anyone help explain or give me some advice as to what to look for in case something is wrong that I might have done?

Thanks,
Scott

Mods:
DP
Apex'i Cat Back Exhaust
Greddy Intake
Greddy FMIC
BNR Stage 2 Twins
Greddy Pulley Kit
MBC
Turbo XS RFL BOV
Clutch Kit
Stock fuel system
Stock motor
Stock Catalytic converter (could this be clogged and bogging me down from when I blew my last turbos?)


I know I need an ECU....please don't bother telling me about the 3 mod rule. I am in the process of getting a PFC, MP, Fuel Pump, Fuel Pressure Regulator, and some 850cc primary injectors....but my question is about the issues above.

 

Cause twins suck, bnr or whatever. Shoulda saved and got the single man. Good luck

 

Also....I am seeing 10-11psi on vai my boost gauge...but could I possibly have a boost leak, that is not huge, where I have to boost extra high to see stock boost levels, and then in between shifts it bogs down? If so, would that explain the lag I am getting with these twins?

I am non-seq, so finding a boost leak should be easy....but I am using all new silicone lines for the 7 active lines, and new silicone lines for the capped off lines.

 

nvm

 

Been there man....I had a T78 on my last FD....I liked my car better on twins, so I opted not to go that route again....but I may end up going with a small single this winter...but nothing like my last setup. Too much money, and too worthless for street use.

 

I notice a little lag with the greddy FMIC. But when it hit 10-12psi it sure didn't fell slow. You might have a leak check those pesky silicone coupler and greddy cheap'o clamps. Your no seq. might be helping with the lag.

 

I remember reading that now that you mention it. I am surprised you didnt like it. Was it tunned by someone who knows what they are doing? Not trying to be a wiseass. Demetrious claims to get t78's to full boost by 3800rpm. That would be pretty streetable to me.

 

how long was your car down? It's summer time now and if the last time you drove your car was in the winter than it would have felt faster. Also check for boost leaks. If you have one, it could be blowing out, making your turbo work harder and hotter

I agree, you should have gotten a single, even if it was only the Apexi RX6

 

Like I said...did not have the financing for a single right now....I am trying to buy a new house and get myself out of debt some, so a single was not on the list of things to buy...because then I would need some fuel and an EMS...so there is another $2000 on top of the $2000-3000 single. Where I bought these twins brand new for $1000....so $1000 or $5000? Plus I had a single before....and I am not ready to do all that again.

It was fine as far as spool....I am talking power and traction. Worthless for me to have fun with...good for drag racing, **** for backroads, street racing, etc...

But my car is seeing a solid 10psi...and it feels like a dog. If my gauge is seeing 10-11psi, then I know the turbos are pushing it....could be a leak, making them push harder, but wouldn't 10psi feel just as strong struggling or not, just maybe spool slower? I am thinking that it is my cat causing too much backpressure from being clogged up, hence my UIM is seeing 10psi, but once my turbines try and exhasut that air, it is backing up, slowing down the turbine shaft, hence killing my power....I don't know. After reading that it doesn't make sense either.

All I know is that my car would be lucky to clip off a 13.9 as it sits right now, when before I was beating WS6's by 4-5 cars.....I don't think I could beat an Omni now.

I am going to check for boost leaks.....also my motor is not having quite as much vacuum at idle....could my motor be taking a **** on me too? It is only at like 12mmhg at idle now...when it used to be around 17mmhg before I swapped the turbos.

So would that be a vacuum leak somewhere in the system, causing:
a) boost leak
b) low vacuum at idle

I wish something would just go smoothly with one of my FD's one day.

Scott

ps: My car was down for 6 weeks.

 

How long they been in? Maybe it takes awhile for the fresh rebuilt turbos to wear in?

 

you can have a boost leak at a coupling and still hold 10psi.....its just that the turbo's will be over spinning to keep 10psi and they will heat up the air and make you loose a lot of power. In addition you'd be laggy

I would check all your couplings, especially the ones at the IC, I know someone who was having problems keeping the couplings on right down by the IC.

Also, your going to experience more lage with that FMIC than with the SMIC so thats also going to contribute.

And yes, if your cat is clogged up of course that could hurt things. I dont think those particular BNR's you have should be much different than the stockers in terms of spool. I dont know about the efficiency at 10psi though, I dont know anyone that only runs 10psi...but I wouldnt think its so much different that it would be that noticeable.

Check those couplings man. make sure they are all REAL tight.

Also, just noticed about your vac dropping....a coupling leak wouldnt do that, it would need to be soemthing after the tb to make your vac drop. The turbo's wouldnt have anything to do with that.....you might have just unhooked something and forgot about it......that would make you loose power also.

STEPHEN

 

I think you've justified reasons for staying with the twins - I share the same feeling there.

though it seems unlikely - could be just a little less responsiveness from the fmic, and a little less effectiveness from the foamies

 

I will check the couplings tomorrow....it is crazy slow though. I let my friend drive it tonight, and he asked if it was even boosting....yeah, it's that slow.

I guess next for me will be the PFC and a midpipe just in case that cat is clogged. It just seems strange....I think it will be an easy fix...but just sucks, I have been without my car for almost 2 months, and now she is back up and running and drives like an 88 GXL. Must be fixed....can't drive a slow FD with a FMIC...that would just look silly. I have ran FMIC's before on my last FD with twins for a while, and it still felt good....nothing like this....and I doubt those Foam intakes could suck that bad. They do suck, I will give them that. I need to figure out a way to get some K&N's to fit with the Greddy Intercooler.

It couldn't be low compression could it? The car starts fine, and idles fine at 750rpm with 12mmhg of vacuum...which is low, but not so bad as to make me worry..just something I noticed. But could low compression make 10psi feel like ****?

 

k+n - the easiest way may be get some hard pipes fabricated, however...

http://border-racing.com/

do deal with foreign orders, and do offer an induction kit that uses k+n filters (looks to me like it will work with a fmic - so I may well check them out). Unfortunately, I haven't seen a pic of it on their online catalog (it is listed in the hyperev rx7 parts magazine)

 

its your giant FMIC with small *** turbos the flow takes too long to travel though the 2 rows and into the engine so til you get a single switch back to your stock mount or just suffer

 

ok and you need to toss that cat and get a large street port or a extend port becuase when you do get a single you will have to

 

won't neccesarily HAVE to, I know plenty of guys... including myself, that runs stock ports on a single setup.... some of us aren't made of money

 

Have you considered getting the car to a good tuner who'll most certainly be able to pick your problem easily?

Pretty hard to diagnose this sort of thing over the 'net, especially when your only symptom is a feeling of low power..

 

I also had 12mmHg of Vacuum when my MAP sensor disconnected (but then again, I couldnt boot at all).

By what RPM do you reach full boost - 10psi ?
I think this can also be used to determine if you have a boost leak - as you would get that 10psi later then usual. I get full boost by about 2800RPM, but I'm not 100% sure that is how it's supposed to be, as my PFS IC can get quite hot sometimes (no, not during racing, even normal street driving with occasional boosting).

 

Just a quick question... someone mentioned you could get new BNR twins for $1000? Could someone please point me to where I can get those? much appreciated...
thanks.

 

I must say, since receiving my BNR rebuilds and having them installed over winter ( I only drive the car from late March-late October) I must say that the performance of mine seem less as well. I even added the SMIC, PFC, intake with them and had it tuned. Seems there is more lag and when there is really strong power it is inconsistant with speeds/gear selection.

 

Are you sure you didn't leave a nipple open on the UIM somewhere? 12 mmHg is a pretty poor vaccum reading for a stock ported engine. With a reading like that, I'd vote for a vacuum leak somewhere. Maybe you nicked a vacuum line during the turbo R&R.

 

the first thing I would try is to check all vacuum lines and then the couplers.Then if I found nothing I would change out all the gaskets.Except maybe for the lower intake manifold.That I might leave alone.If it helps but not enough.change your spark plugs.When is the last time you did that? Last but not least replace your fmic with the smic and see if this cures your problem.Hope this helps.

 

Ok....lots of posts, which is good....here are some answers to some questions.

I had the M2 Large SMIC before this Greddy 2 Row....the M2 is a larger 3 row IC w/ shorter pipes...doubtful my longer pipes can make this kind of a difference.

I installed all new plugs/gaskets when I put the turbos in. I bought every damn gasket I could from Malloy.

I will check for vacuum leaks or boost leaks today and see if I can't find a coupler or line off or cracked.

I bought the BNR's from a forum member who had changed his mind about them...hence the good price on brand new twins.

I will check each gear for full boost and post the RPM's later on.

Thought about taking it to a good tuner...just not any real close to where I live. It will be a 2 hour trip to find someone.....but it will see a tuner if all else fails.

Hopefully your twins don't feel this bad....if so, that is a bad reputation building for BNR Twins...and I thought that he had already fixed his twin problems from his earlier mishaps with them. These are the newer versions that are supposed to be better.

There is no way my car feels slow because of stock ports....it felt fine on the stock twins with stock ports...and these are still stock twins, just modified to flow more air and sustain higher boost levels. But 10psi vs. 10psi should still relatively similar. If they were a bit slower at 10psi, no big deal.....hopefully they would flow alot better at 15-17psi....but 10psi on my car feels like 3 psi on my friends stock twin turbo FD.....and that is retarded.

 

I don't think it is turbo related. If it is turbo related, it happened from the guy you bought them from and not the original builder. Used parts are always a gamble.

12" of vac is your problem... It might just be a kinked vac line istead of one popped off.