Porsche-O-Phile

Yea, the gas out here is pretty bad. I've always wondered why CA with all its emissions crap and regulation and concern over air quality and smog would NOT push higher octane fuel (more efficient, cleaner, etc). It just doesn't make much sense. I want to be able to run straight 91 gas without being dependant on weird stuff like race gas / toluene / etc. just to get to and from work every day. For a dedicated track car, fine - but that's not what this is.

Speaking of lousy gas - it'd be REALLY nice to retain some sort of knock protection like the KLR affords, but I think the only one that's set up anything like that is NZ951, and his isn't "hardwired" into the system, it just gives a warning if knocking is detected.

Let me ask this - if one deletes the CV (such as with a MBC or EBC setup) and retains the KLR, will the KLR still be able to send the "knock detected - kill fuel flow NOW" signal to the DME? I know it won't be able to regulate boost level (since the CV is gone) but I believe there IS a link between the two computers such as is the case with the overboost protection. If that knock protection is retained, why then do we still have people getting milkshakes? Wouldn't the KLR intervene and request that the DME kill the fuel to the injectors?

Also I'm with you on the WB but it's just more $$$ I resent having to spend. I'll probably pick one up though; if I ever had to I could probably sell it for almost what I get it for.

MildMax951

very briefly the klr will still retard ignition in steps with the CV removed. If that fails to stop knock then the strategy is for the KLR to start dropping boost via the CV (which in this case is no longer there so your'e in trouble) There is no fuel cut instigated by the KLR in response to knock, there is a fuel cut instigated by the DME in response to too high an air flow for a given time (as measured by the AFM)
HTH

HY M8NC

I'm doing the Tial for 2 reasons-

1) I spun the boost controller in, and couldn't get more than 12psi-I suspect the wastegate is getting old. Clamping the line sent the boost to the peg on a 15psi gauge.
2) I agree that the shim is fooling the wastegate into holding more pressure. I'm not saying it doesn't work-or that it is a bad idea-just that a Tial with a 1.2 bar spring will be easier to run 15psi consistantly.

I'm not planning on running more than 15psi of boost-and I'll run it on pump premium (92 Octane). I might do a run on the 100 Octane racing fuel we sell. Dunno.

Once I get the number for this set-I'll be working on a turbo for the car. I've posted looking for K26/8 cores-I already have enough K26/6 cores, but still need one more K26/8.

johne

With a 1.2 Bar spring in you wastegate you will *not* be able to run 15 psi. the spring pressure is the minimum boost pressure you can run. So a 1.2 bar spring = 17.5 psi as you lowest boost pressure.

-John

HY M8NC

You are right Johne, I'm going to start with a .8 bar-and swap progressively up the further along I get into the project.

For those keeping score
.8 Bar is just under 12psi
1 Bar is 14.5 (14.7?)
1.2 Bar is 17.5.

The spring determines when the wastegate will open, not what it's max boost can be.

toddk911

"there is a fuel cut instigated by the DME in response to too high an air flow for a given time "

Anyway to tie that signal into the KLR for knock control?

Porsche-O-Phile

That's what I'm wondering. . . Then you could run a Knock block or whatever that detector thingy is called and have IT send the signal to the DME, having the DME kill the fuel before the real problems start. It'd just be nice peace of mind. . .

Anyway, another way to increase wastegate reliability would be to simply use the line that's provided. At present, the pressure from the turbo's hot side (via the banjo bolt) is transmitted to the w/g line via the CV when the proper signal is given. What about a system that placed a vaccum on the same line at all other times? This would effectively "clamp" the wastegate valve shut until the CV opened and popped it open. Much more dramatic of a response, but it'd build a lot of boost in a big hurry and if the w/g spring was a bit tired, who cares. Non-issue at that point since you're using a much stronger force (air pressure) to hold the valve open OR closed. Just a thought. I could work on a design for such a thing if you guys think it'd actually work.

johne

I came up with this idea a while back, then I found that wastegates like the Tial 38mm are made so that they install in the reverse direction of our WG's. This means that the exhaust holds the valve closed and that boost pressure is required to force the valve open into the exhaust stream. So boost comes on really hard and not fancy system is required, just a Manual Boost Controller.

-John

Porsche-O-Phile

Good to know - VERY good to know. I'll check out the Tials then. What's the advantage of a dual-port 'gate versus a single-port one and why do people run 42mm (and larger) wastegates with high-power cars? Isn't that the opposite of what you'd want? I mean, with a larger bore wastegate, wouldn't that take more flow away from the turbo when the gate is open (even a little)? I'd think that strength of signal sent to the wastegate diaphragm would be better than wastegate valve aperture to control "crispness" of wastegate response, but maybe that's incorrect. Another thought is maybe it's necessary with larger diameter turbos to give enough bypass to effectively allow the turbo to spool down quickly to prevent overboost or something - dunno but that seems to make a little sense also. In any event, I'm guessing anything larger than 38mm would probably be HUGE overkill for our cars.

I've also heard MBCs are less reliable than EBCs, but that's another discussion.

toddk911

"What about a system that placed a vaccum on the same line at all other times?
This would effectively "clamp" the wastegate valve shut until the CV opened
and popped it open."

Or an inline check valve (PCV)

mark944turbo

For the money, just get a Tial.

Claus Groth

When the Turbonetics wasteagte failed last year by leaking at the valve guide, I was running 24 PSI boost that dropped rather quickly. I ran this way for several track weekends without incident.

At the end of last year I installed a TiAL wasteagate and a MAF with programmable fuel controller. After dyno optomization, I ran 12.5:1. At the dyno session I still had not been successfull in setting the EBC and ran 24 PSI. HP was 271 and Torque was something like 330. So I presume that I have around 250 HP at 17 PSI. I am still fine tuning the EBC, which is now keeping boost above 15 PSI to redline.

Danno

"hen I found that wastegates like the Tial 38mm are made so that they install in the reverse direction of our WG's. This means that the exhaust holds the valve closed and that boost pressure is required to force the valve open into the exhaust stream."

Uh.. if you look at it closely, the proper way to install a Tial is so that the valve opens into the direction of exhaust flow, same as stock. Just that the Tial can be ordered with a spring 3x stiffer than stock to hold high-RPM boost better. A couple of guys here had their Tial installed backwards so that the exhaust-pressure forced the wastegatep-valve closed. Boost-pressure in the diaphragm was NOT able to open the wastegate and they had tremendous amounts of boost over what was desired (22psi+). FYI, exhaust-pressure gets up into the 50-60psi range under normal operation with the K26/6 at upgraded boost-levels of 15-18psi; you will not be able to use boost to overcome exhaust-pressure. The Tial must be installed so the valve opens in the direction of exhaust flow.

P-O-P, the Welt chips are similar to many aftermarket chips with a rich mid-range. So you can get away with some extra boost. Their saving grace is that they anticipate a dropping boost curve to 11-12psi by redline. So you should be fine with 14-17psi in the mid-range...

Porsche-O-Phile

I'm assuming I'll be able to map that with an ApecI right? I could set it to pull 16 psi or so to maybe 5,500 RPM and then maybe 15 at 6,000, 14 at 6,500? Would something like that work or should I just get the Guru ones?

(Chance for shameless plug here)

johne

You would think that, at first I doubted myself and agreed with you, but then I did a little research and upon closer examination noticed something. The exhaust valve of a 38mm Tial is, if I recall 38mm :b, but the diaphragm that the boost pressure is applied to is closer to 80mm I haven't measured it but my eyeball-o-meter says 80. So the area of each is
3.14*(38/2)^2=1133mm^2 and
3.14*(80/2)^2=5024mm^2

so the boost pressure actually has a little more than ~3 times force multiplier. This means that the intake pressure only needs to be ~1/3 the exhaust pressure + the spring pressure. Also I have never seen exhaust pressure in the 50+ range on these cars, only in the 40's. But who knows the KKK turbine isn't that efficient, so maybe.

Anywat, here is a pic showing picture of a properly installed tial:


The pic comes from this page: http://www.z31.com/wastegate/ they have pics of several Tials installed in this manner.

I was thinking about what you said and at first I agreed (that's why I did a little research to double check my memory. ) Good argument though, I love figuring out exactly how these girls work.
Now if only women were so easy.

-John