Engine/Transmission (1994 - 1998) Cam plate design

[TurboFan]

Hi cam plate guru's,



I am after a plate that fuels to 1200 degrees EGT at any given rpm.

Of course I don't want much smoke so I would make the upper fueling limit the lower of tolerable smoke or 1200 degrees.



That way I have the maximum power available at all times within the limits of smoke and egt. If I want less power, I don't push as hard.



My #12 tst plate seems to smoke and produce HIGH egt's at higher rpm when moved forward far enough to add power over the stock plate at low rpm, but in the mid range rpm there is zero smoke.

That leads me to believe that there is room for more fuel in the mid range, but the top needs to back off.



Do you see where I'm going?



I want mild smoke and/or about 1200 degrees at any given rpm.



Is there a cam plate that will give me that?



A side question. It seems like cam plates would be generally curvey instead of sharp angles and abrupt changes in fueling?



Thanks guys!



Greg

 

[REFLOYD]

get a #0 totally flat

 

[JGheen]

I don't think your going to get the smoke amount you want with the plate you are requesting. But I would agree that it sounds like a #0 would be your piece of pie.



Joe

 

[TurboFan]

Okay, I'll take a look at a 0. Thanks.

 

[pwerwagn]

This is the way I'm reading what you want:

none or minimal smoke and max egt at 1200*, with the most power available at that combo.



A #0 will fuel more than a 12 on top, so you will get more smoke and hotter EGT at high rpm with a 0 than a 12.

I'd suggest using a #10. It has upper RPM defueling. slide it around until you get the smoke/EGT you want on the upper end of the fueling curve. Then adjust your AFC from there to limit fuel lower in the fueling curve. You can play with the AFC position, the position of the foot in the AFC, and the spring to achieve your desired results.



--Jeff

 

[Smokin_Monster]

Anybody have a picture of a #0 plate vs. a homemade version? Difference?

 

[pwerwagn]

You mean a REAL TST #0 vs a home-ground #0???

One difference is the home ground versions still have the rivets in them if you used the stock plate.

Another difference is the TST versions are hardened.



I think it all depends on who made the home-made #0.



Oh, and no, a real #0 is not just flat from the front surface... It is flat but not the whole way... .



--Jeff

 

[TurboFan]

This is the way I'm reading what you want:

none or minimal smoke and max egt at 1200*, with the most power available at that combo.



A #0 will fuel more than a 12 on top, so you will get more smoke and hotter EGT at high rpm with a 0 than a 12.

I'd suggest using a #10. It has upper RPM defueling. slide it around until you get the smoke/EGT you want on the upper end of the fueling curve. Then adjust your AFC from there to limit fuel lower in the fueling curve. You can play with the AFC position, the position of the foot in the AFC, and the spring to achieve your desired results.



--Jeff

Good advise Pwerwagn.

A local member just swapped his #10 for my #12 for a couple of days so I could try it out. Can you believe that! What a guy. I'd mention his name but I'm not sure if that would be a good thing or not.



I plan to do some test driving today, ans probably move the plate around. The defueling on the top end seems to be a good thing at first glance.

I'll update later on.



Take care

 

[tp0d]

I ground my own 10 profile, just do it slow and cool the metal so it doesnt anneal it. I`ve had mine in over a year and it still looks like the day I ground it.



I have the plate set 3/16" from full forward, afc forward and star wheel 10 clicks from stock and I make about 1250 in od lockup pulling a hill, stock turbo with bhaf.



good luck



-j

 

[TurboFan]

Well, I test drove with the #10 in there and it seems to be close to what I want. I plan on seeing if TST will take thier #12 back in exchange for a #10.



The #10 seemed to consistently have barely visible smoke once the turbo spooled up in the mid to high rpm range. It did defuel at the top end keeping the egt's around 1260. All good stuff.

Just for testing sake, I moved it forward a bit and it smoked more throughout rpm and egt's went high, before it got into the defueling range.

Where it was positioned first, seems to be to my liking for now.



Maybe later on I'll cut or modify a plate, but I think the #10 will be good until I get bored and need to engineer something.



Also, I am hitting just under 40 lbs of boost. That seems pretty high, so am thinking it would be neat to find a relief valve type thing that I could put on the line to the wastegate that would stay closed until hitting about 34 lbs of boost, then pop open and allow the waste gate actuator to do it's thing until boost dropped back down to 34 psi.

I'm thinking it would make the turbo produce 100% of it's potential up to the 34 lbs, rather than a gradual opening of the gate before optimal boost is attained.

That could be a retarded idea, but it seems cool to me!



Thanks for the input so far. There's been some good info here.



Greg

 

[pwerwagn]

Your thinking of a Hobbs switched wastegate setup. Some of the guys here are running that setup, do a search and you should find some info on it.



Glad you liked the 10.

--Jeff

 

[Matthug]

At the power level you are at it would be better to swap to either a 16cm non-wastegated housing or a 14cm wastegated housing. I'd suggest a 14 WG'd to minimize smoke. Your stock 12 cm housing will be quite restrictive, make EGT's sore high, and boost is hard to control.

 

[Forrest]

Also, I am hitting just under 40 lbs of boost. That seems pretty high, so am thinking it would be neat to find a relief valve type thing that I could put on the line to the wastegate that would stay closed until hitting about 34 lbs of boost, then pop open and allow the waste gate actuator to do it's thing until boost dropped back down to 34 psi.

I'm thinking it would make the turbo produce 100% of it's potential up to the 34 lbs, rather than a gradual opening of the gate before optimal boost is attained.

That could be a retarded idea, but it seems cool to me!



Greg

There was a TDR issue some yrs ago about the backpressure of the stock HX35 exhaust housing @ 30 or 32psi of boost. It was really a big #. Not only that, above that it's pushing HOT air into the motor. Someone posted the reasonable boost limit ... it's been awhile.



You've got the 215hp pump I assume? You could easily take on an HX40-16 or equivalent, like the hybrids from HTT or II.

 

[Matthug]

My brother was pushing 375 RWHP in his 24V on the stock HX35, at 42 PSI boost (wastegate was wide open, too much fuel!) his drive pressure was well over 80!!!

Anything over 38 PSI and the HX35 is overspinning, but like forrest said much over 32 is just hot air anyway. If your turbo is in good shape the cheapest thing to do is buy an upgraded compressor wheel and housing (60mm) from HTT, then a 14 CM wastegated housing. You can find 14's on here for sale for about $250, and the compressor upgrade is $240, so for about $500 you can have a turbo easily capable of handling 400 RWHP safely.

 

[TurboFan]

Great! Hobbs switched wate gate. Thanks.

Getting the boost controlled is next on the list. I'm shopping for a solenoid valve and pressure switch.



A turbo upgrade will take a bit of research, and a few more discretionary bucks, although it sounds pretty reasonable. Thanks for the tip.

Reducing turbo lag is the next hurdle on the horizon. I drive around empty mostly, and a fair amount of stop and go. The #10 is going to help tons... but will I be willing to pay to get to the big torque a second sooner! Probably.



Of course, then I'll have to NOT use it most of the time or end up getting 10 MPG.



Thanks for all the info!

 

[Forrest]

Here's a thread on the Hobbs started by DF:



http://www.nwbombers.com/forum/index.php?showtopic=18182&hl=hobbs+switch

 

[RonA]

Hey Forrest.

The plate Piers ground for me does a good job of controlling the egts and gives good duration on peak hp. I put a graph on my readers rigs. Not big power, but quite usable. Hit 1150egt about 3/4 through the run and it stopped climbing. Rarely see over 1000 in a roll on from 55 to 85. Defueling occurs at about 2400 and power holds till about 2900.



Ron