Minor driveability problem at partial throttle, high boost.

These turbos are tough! I doubt it will be an issue.

a few guys were saying it was ....... :dunno:

We have yet to see a failure of an EFR turbo and we have sold more EFR's then anyone on the planet to the rotary community.

I will purchase one of these EFR turbo kits one day.

Here is some more info on my situation.


I don't think its compressor surge but something to do with the wastegate.


The problem arises going uphill under high load at low rpm. Low rpm is 2500-3200RPM and it feels and sounds like the wastegate is fluttering which ends up like a jerking motion of the car. it only does it when the wastegate tries to control the boost. in order to get it in 4th you must be going uphill to drive the turbo to boost at that low of an rpm. but when you live in the mountains you have lots and large uphill sections, which sometimes you leave the car in fifth gear and get this stupid issue.


It happens when you floor the car at low rpms and keep it floored, the wastegate feels like it is opening and closing or fluctuating, it steadies out with rpms as the rpms climb and then goes away completely. The car also does it at partial throttle as well over certain parts of the rpm range/boost pressures. does not do it at full throttle mid to high rpms at all.


Remedy? Any suggestions? should I add more preload to the wastegate spring?


I am running the stock wastegate canister from BW, medium pressure spring. I am running the stock BW supplied boost controller with the powerFC running it. The boost source is from the turbo like BW sent it to me. I am running the car at 6,500-9000FT above sea level if that matters.


When looking at my water injection, it kicks on at this low level and when it starts jerking it looks as though the turbo is boosting on and off as the light is coming on and off on my water injection, so it makes me think that the UIM is seeing on and off boost patterns. perhaps the turbo is surging?




I tried different boost settings, different injector duty cycles, shut off my water injection, none of this changed anything. it doesn't seem ignition related, and my AFR's are good. its something with either controlling the turbo or the turbo itself IMO. but willing to listen what others think.

That does sound like compressor surge. The turbo is feeding more air than the engine can handle. Is this at Wide Open Throttle or Part Throlle?

If it's at part throttle, try and lower the boost in that range as low as possible. I knwo you said you fiddled with the boost, but for grins, hook up the wastegate straight to the compressor source to run wastegate spring pressure. This may help, then you need to set your target boost table lower in that range, if that is indeed the problem.

Definitely surge. My 9180 does the same thing if I have boost duty set to 100% at all throttle positions. Are you using a stand alone controller or the ecu to control boost? Lowering your "spring pressure" value could help so it allows the gate to open sooner, but you'll lose some spool. I also get surge if I try to run too much boost at too low of an rpm.

surge it is.

I am using the ecu to control the boost.

I don't know if the PowerFC can do this, but set the boost to TPS based, if you can. Then set the values to 0% Duty cycle if throttle is 75% or less.

Does anyone has a kind of a good basemap available (afr, ign l and t) for a 13B with efr8374.

I am short of tuning a FC with turblown efr8374 IWG kit and Vmount. It will also run Rice Racing WI pre compressor and adaptronic FD pnp ecu on a rywire custom harness

The aim is to run up to 2 bar boost in the midrange and at high end taper boost down to stay into an efficient turbo regime and avoid high backpressure and exsessive turbo speed.

Ideally the ignition maps would already be filled with plausible numbers for pump fuel up to 2 bar or more in the mid rpms.

For the moment I am waiting for the correct injector extenders for the ID1000 (supplied with 11mm instead of 14mm ones) and I have to find a solution for the EGT bungs that are welded wrong way around on the manifold (small end of the taper out), which is a bit of a pita as it feels impossible to get a tap started straight in the too small hole.

Did you read the Borg Warner setup instructions? How many turns of preload do you have? How is the CRV (Compressor Recirculation Valve) connected to your system? Is the boost solenoid valve connected properly?

I got the car recently. It's street port with bolt ons. I enjoy the twin turbo response but I'm thiking of going the EFR way. Twin scroll with two EWGs but which one is best for fastest spool possible and around 400whp? 7670? or 8374?

Either one are the best turbos for the 400rwhp range on a 13BT depending on application.

EFR 7670 will have slightly better response and the ability to run very high boost at low rpm without surge.

EFR 8374 will make the 400rwhp at a slightly lower boost.

I would choose the EFR 8374 for 90% of the 13B applications.

So at around 16 psi on premium gas how much power would each make and and what rpm range would each come on?

Reeeeeally depends on the rest of the set-up.

I have done 340rwhp on 10psi with my 60-1 and it has also taken me 16psi to do 340rwhp on the same turbo, same engine just different intake/filter on the turbo and catback.

I'm going to guess it would take 16-20psi to do 400rwhp on 7670 (took 18psi on my set-up) and around 14-16psi to do 400rwhp on the 8374.

We did 509 at the wheels on mustang dyno. Running a streetport E98 fuel and 8374 with 0.92. 4inch open exhaust (race car).
What bothered me was the spool as it took all the way up to 4k to fully spool. I cannot understand why.

Well it's a big turbo. But thank you for sheding some light onto this I think I'll go for the 7670. I wanna achieve full boost by 3k

I think you mentioned that you can get a new 99+ spec 13B-REW from Mazda if you are part of their race program for under $3,500 with no core.

So if one buys an IWG turbo kit some where between $3700 and $4289 and add supporting mods such as intercooler, exhaust, fuel system, and tune.

One could have a brand new engine, super simple quick spooling single setup and make 400 whp on pump gas for under 11k. This if you started with a bone stock car.

Yup.

As far as making 400rwhp on pump gas it still depends on the set-up.

What catback you run can gain/lose you 30rwhp, whether you decide to run a high flow cat can gain/lose you another 20rwhp, intake/air filters on the turbo can gain/lose you 20rwhp.

On the other hand you could select all the most restrictive peripherals and put water injection on and crank the boost to 22psi and still make 400rwhp on pump gas.

True. One could also do 400rwhp on stock engine, stock turbos with just the right selection of peripherals and tuning.

I had a very similar filter on my 9180 IWG setup and I think it may have contributed to my worse-than-normal boost creep issues. I also found that it dropped boost pressure without the filter but I admit I didn't put 2 and 2 together until hearing similar stories on different cars.

We have a velocity short stack with a gauze as filter. So definitely breathing easy. Split is at 10 from 3500 upwards.
We cannot afford to have sluggish response down low as it's a drift car and car needs to be responsive on/off throttle. ECU is Adaptronic E1280s. If you give me your email address I can send you the map to have a look.

Can you post the dyno sheet? Done a compression check, and pressure check on the intake side?

Where did you place the 6" velocity stack and air filter? I ended up returning both parts, since I couldnt find where to mount them without cutting stuff up!

From this thread where I put the first V-stack and 12" filter on my old 60-1 hybrid.

https://www.rx7club.com/single-turbo...k-pics-865265/

Then when I went to the EFR 7670 I used a Vibrant 3.5" to 6" V-stack and the same filter and a slightly shorter 3.5" intake tube (using the FD HKS T04Z turbo manifold).
https://cimg5.ibsrv.net/gimg/www.rx7...021149382c.jpg
https://cimg6.ibsrv.net/gimg/www.rx7...d59f58aec1.jpg