You can put some grease and grit in the V-band and twiddle it back and forth to lap it in too if it isn't too far out.

Had luck with that on the 1st v-band I welded where I hadn't learned that if you weld it in one go without a heatsink it will warp.

 

I've also had some luck with RTV copper... but I wouldn't try that on the turbo v-band. I used it on the v-band further down my exhaust.

 

There is a special efr v-band flange required for proper fitment. I don't know if it comes with the kit or not, but i made do with a regular male v-band flange that i massaged with a die grinder. The leaking was fairly minimal, and pretty much self sealed itself with carbon after running a few tanks of fuel.

 

This looks like a good thing. If I had known about these I would have grabbed a couple.

 

That gasket is legit

I can't count the number of single turbo FDs I've been around with leaky connections at the DP to turbine discharge.....

 

Would that gasket be able to take the heat? I wish there was a thin multi-layer copper gasket for vbands.

I just finished switching over to iwg. My car has large streetport, 3.5inch dp, 3.5 inch mp and a FEED ti catback which is slightly bigger than 3inch.

With that said, im holding 16psi with a 2.75inch restrictor plate in between my mp/catback.

This is with basically no preload and a turbosmart eboost street boost controller.

With 3 turns preload, no boost controller and no restrictor plate I was creeping to about 18psi after 6k rpm.

 

^Fancy that, the restrictor plate did indeed make a difference

 

ArmenMAxx Would that gasket be able to take the heat? I wish there was a thin multi-layer copper gasket for vbands.


100% definitely not.
But it is super easy to use hole saws or tin snips to cut out many thin stainless sheets into multi-layer stainless (MLS) gaskets that DO survive.

I just finished switching over to iwg. My car has large streetport, 3.5inch dp, 3.5 inch mp and a FEED ti catback which is slightly bigger than 3inch.

With that said, im holding 16psi with a 2.75inch restrictor plate in between my mp/catback.


Yeah, it sucks to have to run a reducer (check that thing frequently, they bow out away from exhaust flow over time).

BUT I found running a 3.5" DP and Midpipe to a 3" cat back to limit boost (on an EWG system) gave better spool than just running 3" turbo back that didn't boost creep.

Did you find the same thing?

 

I definitely remember FEELING my setup having better response when switching from 3inch to 3.5inch. Especially transient response however in 4th gear high load it would hit 10psi at about the same rpm. Same can be said about switching my 8374 from ewg to iwg. It feels more response but I hit 10psi within 100rpm in high load.

I should note that right now I am hitting 16psi and holding it to redline without any creep. Its possible that I may be able to lower the boost more with my boost controller. It doesnt make sense, but I am able to hold lower boost with the boost controller vs no controller and no preload. Perhaps the controller is pushing door open further somehow? Again, doesnt make sense to me. Without the controller I would hold 14.5 psi and start to creep after 6k rpm. This was with the restrictor plate. I never wired the door open (lazy) to see how low my setup can hold boost mechanically. Either way, my afr's are at 10.0 and it still feels f*cking awesome as is. Sounds higher pitched vs my re-routed long runner ewg setup also.

 

I definitely remember FEELING my setup having better response when switching from 3inch to 3.5inch. Especially transient response however in 4th gear high load it would hit 10psi at about the same rpm.


Ah yes, that boost response is what I meant when I said better spool.

Peak boost by rpm with EFR 8374 is going to be dictated by the compressor map surge line.

Can't fix that with more exhaust energy from larger exhaust or tighter AR. You could fix it with bigger ports or another rotor.

it still feels f*cking awesome as is. Sounds higher pitched vs my re-routed long runner ewg setup also

Sweet! Put more vids up on Youtube if you haven't already. I enjoy watching those!

It doesnt make sense, but I am able to hold lower boost with the boost controller vs no controller and no preload. Perhaps the controller is pushing door open further somehow? Again, doesnt make sense to me. Without the controller I would hold 14.5 psi and start to creep after 6k rpm.

It is possible that your boost controller settings are CLOSING the wastegate some at high rpm which increase exhaust manifold pressure and chokes the engine VE in the high rpms so limiting boost creep.

As I described above to ptrhahn.

 

Dont want to clutter this thread. I did make a short canyon vid to showcase how responsive the IWG is and posted in my track vid thread.

https://www.rx7club.com/racing-kills.../#post12040441

 

I finally got around to examining my 8374 turbine housing. I'm the guy that has seen creep as high as 26 psi. The casting looked ok but there was definitely some room for improvement. I spent about 4 hours porting it today. I opened up the runners all the way to the gate. I tried to shape the runner entrances shear the gasses more efficiently. Unfortunately I won't be able to report the results for some time. I still have to finish assembling the motor and break it in before going boost crazy.

 

Nice work on the runners

 

We just had another EFR IWG FD( REW SWAP ) hold 11psi on the dyno and street... OEM medium BW actuator with 3" full exhaust.

Keep in mind that Armen has a 3.5" DP/MP and 3.25" catback so its expected that he will be at much high boost pressures for a 42mm single WG.

 

I also finshed my setup and tested it yesterday in wot it hold boost at 11lbs max. my setup is 8374 with Bw actuator, Turbosource cast mani & downpipe, SMB hi flow cat with racing beat dual tip. I have to say you guys were right this setup it built boost very fast at partial throttle.

 

^with the HFC and restrictive RB dual tip CB, I wouldn't expect any kind of boost creep issues

 

Update: Well, I finally got around to pulling the car apart again to install the new housing, and it didn't go well.

First, somehow the tension nut on the actuator shaft was frozen on, and even after PB blaster and using a vice grip to hold the shaft from turning, it snapped the shaft off. I'd say it was impossible to have cross threaded, since it was 1/2" up the shaft where it sat.

The big problem, however, is I can't get the turbine housing off. It's been soaked to death in PB Blaster, and I tried both beating on the actuator bracket with a mallet to try to get it to rotate a little, and actually bolting the whole mess back in the car so I could get some leverage on it. Nothing. Like it's welded together.

A couple other observations:

1. With the T4 divider removed, it's really going to need an undivided gasket. That center piece is just going to flap in the breeze and just break off and go into the turbo. If I cut it off, it'll expose the material sealed inside.

2. The studs for the manifold are a hair too short. I used the crimped copper clad nuts, since the flangeless hardware store type nuts it came with would have no way to stay tight—there's no room for a nordlock or other washer, and the copper clad nuts are not that tall but really needed a couple more threads to get through the crimp. They came off REALLY easily. I don't know if it was leaking, but it would have if I did more than cruise it around the street.

3. Maybe I'm just in a bad mood now, but I am skeptical that this will actually work. When you look at the flow paths for the two divide wastegate runners, they are pretty good. I think the hole at the end is just not big enough, but I guess we'll see eventually.


In any case, I'm pretty much at a standstill. I might as well ship the turbo back and see if turbosource has any way to get it apart.

Also, can somebody tell me why every picture I post to the forum is upside down?!

 

I had a similar situation happen to me with the stuck housing. Literally had to tighten it back down in the engine bay and use a crowbar to wedge it off after using a blowtorch to heat it up. Sounds brutal but like you said, mallet, rotational forces, plus a can of pb blaster didnt do much.

Best of luck

 

According to this graph, you're WAY off above 4200-4300 RPM to Redline (according to factory tire size and final drive ratio).

The bumpiness of that curve suggests the engine would prefer a leaner AFR. Hey, my Integra loves 13.2-13.4 AFR on CA's 91 Octane, and MOST tuners would suggest 12.5ish for that car. Just saying...Dave should have known better by looking at that and tracing what the engine is asking for.

Timing could also be too conservative in this region...

 

Mmm. Not really. Mid 11's is where these cars ought to be... most rx7 tuners will tell you to BACK OFF if you start to see 12's at WOT.

It's more than likely tires slipping on the dyno—the same happened when Ray and I dyno's it.

 

Anyone try a single external gate setup?

 

Ptrhahn, my turbine housing hopelessly stuck too. I tried several different approaches. Nothing was working. You must be very careful if your going to try and hammer it off. The housing will **** and bind the fins on the turbine wheel; possibly bending them. What finally worked was using the housing bolts as jack bolts. I cut a few lengths of 5/16" diameter rod to use as a spacer to reach the other side of the center housing. One of the bolts, I used a piece of flat stock against a coolant boss. Since there are 5 bolts, you'll have to pick the best 3 so you can push it off evenly. Be very careful, spin the turbine wheel every time you turn a flat on the bolts to make sure your not binding the wheel. It's a little cumbersome and you have to fiddle around to keep the jack rods in place, but it works and doesn't leave elephant prints all over your housing from a BFH. Good luck with it.

 

I forgot to mention, I only had one summer and roughly 2500 miles on the turbo. And as I stated above, it was hopelessly stuck. I think I'm going to try some Cop-Graf anti seize lubricant on the housing and bolts. It's rated to 1800°. I work in a steel mill and they use this stuff on the coke oven door bolts. The doors get red hot. The guys that that take the bolts off say it's stays intact.

 

Thanks. I'm not going to mess with it and risk hurting the turbo. I'll send it someplace.

 

UPDATE:

I got the turbo apart, and the whole shebang reinstalled and leak free. I haven't, however been able to find enough space/lack of traffic to open it up past 6k in 4th. At 6k, it's showing about 12 psi.

It appears the spool may be hurt a bit, or at least it may need more preload on the canister (I'm at zero) to prevent the door from cracking open (maybe there's more pressure on it now). I'd also swear the car is louder now, but maybe not.

As soon as I can find a quiet moment out on the roads, I'll know for sure—but the boost is steadily climbing at that 6k/12psi mark, so I'm not necessarily optimistic.

The pattern is, if you watch the trace you can see it crack at about 8 psi like it's supposed to, then there's a flat spot for a while, and then it'll start to climb in higher RPM. All will be revealed soon, and then I need to figure out how to get the PFC boost control working.

If it doesn't do much for the top-end boost creep, I'm inclined to go back to the unported housing and live with it.