New Tomei M7960 makes 338 whp with wastegate actuator disconnected from flapper...

[Mirage]

:confused:

So it made 1.4 kg/cm2 of boost with the wastegate flapper wide open, in fact it would only make 1.4 kg/cm2 of boost, regardless of what was done to try and control boost. In case you missed the other post, this is my second turbo, under warranty, the first ones wastegate flapper broke while attempting to set the boost (which was never accomplished either, kept overshooting).

The Tomei documentation states that the actuator is preset for .8 kg/cm2 from the factory, so I started there with the PowerFC boost control, adjusting the duty cycle all the way down, and it always overshot and hit boost cut at 1.05 (boost cut is .25 over target) right at 5000 rpm. I also upped it to .9, moving boost cut up to 1.15, but the same thing happened. I loosened up the actuator in .5 turn increments ending up at 1.5 turns, to the point there was no tension on the wastegate actuator at all, and it still boost cuts, its just laggier and hits at about 5800 rpm instead. I got the car to the tuner yesterday (Ed Senf) unfortunately without having stable boost. We bypassed the boost control solenoid to eliminate it as the problem, and ran a straight boost source to the wastegate actuator, with the same results, no boost control, we even watched the actuator arm moving and opening the flapper. At this point we disconnected the actuator arm completely from the flapper arm leaving the wastegate flapper wide open, which you would think would give you 0 (or at least minimal) boost. He upped the boost setting to have no boost cut, checked the fuel/timing to be safe, and we got our first pull to 7500, with boost hitting 1.4 kg/cm2, making 338 whp. At this point we are completely baffled. We made a couple of runs and then hooked the actuator back up and he fixed the fuel/timing and tuned it for 1.4 kg/cm2 since that was the only number we could hit at all, I believe we ended up at 337 whp and like 299 ft/lbs, I didn't bother getting those charts printed out, this was a waste of my time and the tuners time. Tuner thinks from looking at the charts that the exhaust seems choked up on turbo for some reason. On the last runs, power flat lines from 5500-7500 rpm. Short of a banana in the tail pipe i'm not sure why it would act that bad.

Major info for those that might have any ideas...
S14 SR20DET (zenki)
Tomei turbo manifold, turbo elbow, and obviously turbo, 740cc injectors
PowerFC L-Jetro with boost control kit
Z32 Maf
Blitz downpipe, 3" testpipe, RS-R catback.
All your standard off the shelf stuff that should work.

So anyone have any ideas on why I have no boost control at all on a turbo that tomei supposedly did so much dyno time and research and spec'ing for a sr20? We were all out of ideas, and at this point I regret not doing a 2871r and being done with this back in july. I haven't pulled the turbo yet, i'm getting tired of fucking with this.

Runs with wastegate actuator disconnected...I do have a misfire up top from plugs, still running bkr6e's, that are probably fouled from all the boost cuts.
http://img195.imageshack.us/img195/1369/dyno11310.jpg

[slider2828]

WOW that is pretty frustrating man.... Back to good ol garrett....

[JonGu]

So you're hitting 19-20psi with the flapper wide open/swinging loosely? That doesn't seem right at all.

What happens when you disconnect the Power FC boost control and run off the wastegate spring pressure?

[Om1kron]

Yep, those new crazy ass borg warner turbo's are looking real good right now.

[Mirage]

So you're hitting 19-20psi with the flapper wide open/swinging loosely? That doesn't seem right at all.

What happens when you disconnect the Power FC boost control and run off the wastegate spring pressure?


Yep, wastegate flapper swinging free and wide open, shouldn't be making boost period.

We bypassed the boost control solenoid completely and ran the boost source straight to the wastegate, it was the first thing we did when we got in on the dyno after I talked to the tuner about the problem. It was only left "on" in the pfc to see the boost readings from the map sensor and to have a boost cut in case it got too high.

Those BW's do look interesting though.

[codyace]

Certyainly intersting that it made boost, but I think anyone with an internal gate car that is making power, realizes that the flapper is open most of the time anyway...it simply can not keep shut with that working against it in regard to the low pressure in the downpipe and high pressure area in the turbine housing (backpressure)

YOur tuner is absolutly right in that there is a TON of backpressure in these little turbo setups...it's the nature of the beast. I mean with my car running right off the gate, it pushed itself open to 20/22 psi at times. It took a ton of boost controller time to get the gain set to really control it.

The only true way to get big power boost control is to go external gate.

[Def]

Certyainly intersting that it made boost, but I think anyone with an internal gate car that is making power, realizes that the flapper is open most of the time anyway...it simply can not keep shut with that working against it in regard to the low pressure in the downpipe and high pressure area in the turbine housing (backpressure)

YOur tuner is absolutly right in that there is a TON of backpressure in these little turbo setups...it's the nature of the beast. I mean with my car running right off the gate, it pushed itself open to 20/22 psi at times. It took a ton of boost controller time to get the gain set to really control it.

The only true way to get big power boost control is to go external gate.

I'm going to disgree here. The WG actuator on my car is just an adjustable Garrett, nothing special, and about 8 PSI base pressure. With a little preload it'll hold closed all the way to 20 psi or so down low. Up high, I agree it is hard to get the boost to stay up with an internal gate. That said, it doesn't seem to be his problem at all.


For a data point, I had the clip on my WG actuator arm fall off at the track(basically went plastic from the heat). 0.64 A/R GR2876R, WG actuator completely hanging open, and it'd make about 1 psi somewhere around 3.5k RPM, then slowly creep to about 3-4 psi at redline. It felt like a B18C in power delivery with 264/264 cams... haha

[Black240Ct]

interesting.. cool to finally see one of these turbos' dyno sheets. i wonder how cams would effect the dyno numbers

[RPS13-604]

these turbos dont seem to be doing to well one of our local guys has this tomei turbo and it started to blow oil into his hotpipewhen it was idleing right when it was installed 0km on the turbo ended up selling it for 500 cause tomei wont warrenty it

[Sileighty_85]

Dont some 2871R's have a similar issue and its fixed by dremeling open the WG hole a little bit?

[Mirage]

2871r's might have boost creep and spike issues, but this is complete lack of boost control, the turbo makes 1.4 kg/cm2 PERIOD, it doesn't change regardless of what is done to anything that can change the boost. I haven't ever seen any turbo do this.

That chart is useless, I merely posted it to show whats happening with the wastegate actuator disconnected. It spools a bit quicker with the actuator back on and made more torque once the fuel and timing was fixed. Horsepower stayed the same, it just flatlines like it is being choked out by wayne brady.

When the first turbos flapper broke (same problem, unable to control boost) it would only make .3-.4 kg/cm2, though it did manage to make 1.05 one time after I thought the flapper broke, but I'm not exactly sure when it broke completely, so it could have still been intact at that point, or it could of been missing completely.

At this point i'm completely stumped, as well as everyone that i've talked to so far about the problem.

[Def]

Do you have stock cams? If so, that's the cause of the power choking down around 320-330 rwhp. With stock cams the motor breathes so poorly at high RPM that there just isn't enough flow area over time to flow much more air.

This was covered in details on Freshalloy back around '05-06ish before it started sucking over there.

Get some cams and you'll make more power. That turbo sounds like junk though.

[Mirage]

Yep, stock cams for now (and intake manifold, not that it matters here).

At this point i'm not even concerned about the power numbers, its about why I can't even control the boost on the damn thing, thats what i'm finding extremely annoying about this. I can understand spikes and creep, at least you know its attempting to do something.

I'm definitely unimpressed with tomei thus far...we'll see what they have to say about it now.

[rc1honda]

I agree that the turbo sounds bad. But I did have a similar problem with my 2871. Turns mine was a simple fix i had a lot of boost leaks around the incooler piping. So many that it coudn't build enough pressure to build boost or even blow pipe off.

I would get a new turbo, but also check first for anykind of massive boost leaks. Like around the intercooler and maybe up near the fuel rail and injectors.

[Mirage]

No boost leaks, I pressured tested the system to over one bar before going to the dyno. I replaced every coupler on the car with brand new samco's and brand new t-bolts to get rid of the hodge podge mix that was on the car.

[steve shadows]

Since tuning a few of the larger hot side 2871R variants I would have to say it's a better way to go if you'r going with a gt3071R T28 hot side or example or even the 2871R go with the 0.86...any difference in lag can be made up with a skilled steady state dyno facility or tuner. It's marginal for the more boost controllability and better peak output at boost.

For your issue, have you tried just removing the wg completely from the turbo? (sorry if I missed that you did that already). 1.4 bar is a bit high to be sitting up at with no control or blockage to the port. What is the turbine size say compared to a 2871R .64 or another T28 Variant

[Mirage]

Turbo is on its way back to Tomei usa, they want to look at it. Best Tomei engineers in Japan could come up with is that my exhaust and intake flow too freely, causing it to spool too fast...WTF??? My tuner straight laughed when I told him that one. I really hope something was lost in translation and that isn't what they came up with. Apparently they spent last week trying to replicate the problem on an S14 SR20.

Some interesting stuff that I found out when I pulled the turbo. First the wastegate flapper hits the o2 housing (which is a Tomei) at ~45*, it will go a full 90* but it sticks a bit at the 45* mark and takes some jiggling to get it back. I think thats what broke the first turbo. It hits in 2 places, from the marks in the carbon best I can tell, a bit on the flange, and then some inside the elbow itself. I didn't get a chance to put some air pressure on the actuator to see how much travel it actually has.

Second, the wastegate flapper and wastegate hole, are the exact same size as the stock S14 BB T28, 23mm hole with a 33mm flapper. This just baffles me, because Mitsubishi and Subaru guys running td06-20g's with internal wastegates usually end up porting the wastegate hole, and running an aftermarket 34mm flapper, and have been doing for many years. Tomei could of easily had the wastegate hole 28-30mm on this thing for better boost control, especially since it already has a fairly large flapper, instead they threw on a pretty looking actuator. I'm waiting to hear back about this one.

Steve, the flapper was disconnected from the actuator and open a full 90* . It lagged, but still made the boost. Specs wise its

Intake - 60 trim, 52.6mm Ind, 68mm Exd
Exhaust - 88 trim, 54mm Exd, 61mm Ind

Intake side is dead on for a td06-20g, exhaust side is a bit different.

I could always throw a Tial MV-S on the manifold, or hog out the wastegate hole, but I don't feel like screwing with a turbo that was claimed to have so much time spent on it for an SR20, it should work out of the box as claimed.

[smelly240]

you need to port the wastegate hole... I've had to do this on a number of turbos with internal gates. 16g's and t2 30r turbos mostly.

draw an outline of the flapper and take it out to about a mm from it all the way around. id bet its under 25mm diam right now.

[Mirage]

I could always throw a Tial MV-S on the manifold, or hog out the wastegate hole, but I don't feel like screwing with a turbo that was claimed to have so much time spent on it for an SR20, it should work out of the box as claimed.

you need to port the wastegate hole... I've had to do this on a number of turbos with internal gates. 16g's and t2 30r turbos mostly.

draw an outline of the flapper and take it out to about a mm from it all the way around. id bet its under 25mm diam right now.

That and the wastegate flapper still hit the o2 housing. I was pretty close to doing it anyway when Tomei wanted it back.

[Def]

Yea, I mildly port the WG hole of every internally gated turbo I throw on my car. Doesn't take more than a minute, and makes a big difference on boost control and helps eliminate spiking (actuators don't move that fast when you come on boost quickly).

[codyace]

you need to port the wastegate hole... I've had to do this on a number of turbos with internal gates. 16g's and t2 30r turbos mostly.

draw an outline of the flapper and take it out to about a mm from it all the way around. id bet its under 25mm diam right now.

Ah yes, the DSM mod! Works well for sure, like you it seems like this was so common when I was younger that we'd get 4-5 local guys at a time to have us take a metal bur to their turbos to help em out haha.

[JDMbyBlood]

Any updates?

[Mirage]

Yea, I got tired of waiting around on Tomei, FRSport is exchanging it for a 2871R.

The turbo got sent to japan, they replaced the flapper with a new one piece design, inspected it and found nothing wrong, sent it back to FRSport and told me the engineers in japan would get back to me on how to best go about it while they tested setups to figure it out. I waited and waited and kept getting nothing. They also told me that the wastegate actuator is supposed to be non adjustable and is preset from the factory (and that they reset it). Pretty odd seeing how when they tried to deny the warranty on my first turbo (the one that broke the flapper) their first words were that I should have loosened the actuator to set boost. Its also threaded in 3 separate sections and has a turnbuckle so you can adjust it without removing the end from the turbo, seems kind of silly to have all that for a "non adjustable" actuator.

They might have seriously been trying to figure it out, but they didn't communicate for shit, all I got was they think your intake/exhaust flows to freely bullshit then nothing. To say i'm dissappointed is a serious understatement.

I will probably throw some cams at the car (most likely some JWT's, thinking about picking up a pair for my vg33er xterra as well and just have a cam party) and go for a retune after getting the 2871 on there.

[EDacIouSX]

wow interesting.... I was kind of interested in these turbo's. Borg warner really is looking good.

[UNITEDMASTER]

This is funny cause when I first saw these turbos in the flesh,and really looked at it ...To me its just a china turbo with a fancy WG actuator & Tomei engraved on the compressor.

This is my opinion only I could be completely wrong but thats just my opinion only. And based on their latest Power chanele issue these are not that impresive to me VS the tried & true garret combos for the price.If your looking to do a comfortable high 360-70ish HP max tune, internal gate(+ a quality EBC) ,T2 footprint

[epiphany]

Any new updates on this turbo?

[steve shadows]

What were you expecting to hit output wise if you have an issue with the kit? just curious?