Not to mention a boost elbow creates a more drastic response from the wastegate actuator because the spring loaded check ball BLOCKS the signal to its threshold. When it opens, the gate acts fast and can cause boost creep, surges etc.....though it's usually not felt. The needle valve version still allows a linear boost signal, but bleeds off a little pressure so the actautor sees only a percentage of the pressure. This in turn makes the compressor build more pressure until the wastegate sees enough to open. If you put a pressure gauge on the actuator side of the hose you'd see the actuator is still seeing 17-20 psi while tru intake pressure is closer to 35-37. I don't like boost elbows because they are not dynamic with the engine. Order up any aftermarket boost controller like a turbosmart or whatever, and you'll see they operate the same way with a bleed orifice. Those that think this little bleed-off is costing them boost are over-concerned. The amount of actual air mass lost through the orifice, or valve, in the case of a DIY model, is so minute in relation to total air mass throughput, it really is an un-measurable amount. Boost elbows are a cheap and easy gadget to sell along with a plate that originated years ago in the diesel aftermarket. Boost CONTROLLERS, however, are a much better design, and you can duplicate that $80 aftermarket controller with $5 from ace hardware just like Chimpo said.

Chris

So, you mount the valve in the cab?

You definitely could...just by placing another line on the exhaust of the needle valve to air out into the engine bay, and run longer lines to and from the wastegate actuator. You could adjust it on the fly that way. I didn't go that route, mine is mounted on the turbo...set it and forget it after a little trial and error. In all reality, I don't run one anymore. My secondary turbine is large and drive pressures aren't high anyway, nor is the turbo overspeeding. I used my wastegate actuator to control a butterfly valve in one of the turbine volutes of the secondary to force all the exhaust through one volute for better spoolup down low. Then the butterfly opens by boost signal and allows flow through both volutes. Call it a basic variable geometry turbine if you will....but not really in the true sense of the word. It's a wastegate in a better place :)

Chris

hey chris,

what's your opinion on this? i have a banks bighead wastegate. should i:

1- keep it as is? it's adjusted as far as it can be.

2- add a bleed off valve to it?

3- add a bleed off valve and put the stock one back on?

or anybody have any thoughts on this? i still have my stock actuator so it'd be an easy swap if it's worth it.

Leave th big head on, it has a higher operating threshold as well as a better pre-load spring for higher boost. The stock gate actuator can flutter under boost of 30 or higher, not that it WILL, but it can as mine did. I would, however, add a valve to it. you can always close the valve entirely for normal operation, or start to adjust it if need be. 35-37 psi is easily attainable with the stock HX35, and I would use every bit of it. If you engine is modded enough to provide the drive energy then it can benefit from the extra air. An important mod for the stocker as well, especially at the ceiling of it's map, is to open up all 6 cylinders to the wastegate. Stock The gate only relieves 3, and causes some pretty high drive pressure on the front 3. If you don't know about this or haven't done this yet...it's a highly recommended mod. You'll lose the pulse separation in the twin scroll turbine, but the trade-off is worth that loss.

Chris

are you talking about getting rid of the separation in the turbo mounting flange?? i haven't done that yet. that doesn't increase lag?

Ok, so does anyone have any hard dyno figures with just doing the air filter, fuel plate moved forward all the way (99%), AFC (we just call'em aneroids here) moved all the way forward, 2 turns forward on aneroid adjusting screw, boost controlled to 35lbs?

How carried away can I get with my stock auto trans?

I would say thats about it with the auto tranny....

I hope you have a pyrometer and boost guage at the very least.

Well, we'll eliminate the aneroid as a variable since it won't do anything to the horsepower figure, nor the preload screw or tension wheel. The power output will vary depending on what year 12 valve you're talking about, and I don't have any hard figures for you, but with a stock plate forward, and a good free flowing air filter, you might gain 35 or 40 horsepower. If you go one step farther and open up the exhaust better you might see as much as 250 or so on a 94-96, and maybe 275 on a 97-98. Torque should go up a few hundred as well. As far as what the stock trans will hold, that's subjective. I could drive 700 hp on a stock trans and make it last, or I could drive the trans wrong with 250 and make it smoke. Generally, 300 is probably pushing it a bit without a little modification to the trans for longevity and strength.

And Johnny, sorry I didn't see your post till now, for some reason I didn't get an update in my subscriptions......but....ther are two ways to do it. Either remove some of the scroll devider at the inlet, or remove the backplate, open the wastegate, and with a 3/4" or larger drill, bore down through the existing wastegate hole and continue through the devider there. I found when I was playing with the stock HX35, that removing about a 1" square area from the inlet was sufficient to equalize pressure in the scrolls, and a lot easier than the latter version of drilling. As for lag, you won't feel it, but the engine will very much like equal drive pressures on all the cylinders. You'll lose the pulse effect, but it's a small trade off.

Chris

thanks, chris. no problem on the time frame. i know you're busy trying to live in every state in the union. :poak: :ha: :ha:

i'll definitely look into this. i haven't ever had the back of that wastgate off. should be interesting. :U:

oh yeah, i made that needle valve for my wastegate line. NICE :up: