Those of you who work with turbines in plants and/or heavy equipment does Gregg distributing sell a cheap 0-30 lbs oil/fuel pressure guage?

I want to do the p-pump banjo bolt fuel press. guage install with the needle valve. The parts lists says the guage ten bucks at a "surplus center" store.

I'd skip the isolator and temporarily mount it to the cowl with zip ties where I can see it for test drives then zip tie it under the hood somewhere. Think It'll work?


Or, Tate, you have an old one that was meant for the trash rollin' around in your tool box?

How about a cheap drive pressure guage for a drive pressure guage? I've read I need a coil of copper tube to cool the exhaust a little before it enters the guage and some kind of little pill box (for lack of a better term) I can stuff with steel wool to trap soot before the guage. 0-60lbs shold be good there. Where is this best installed Mike? Manifold like I did for my pyro? Weld a bung in the downpipe?

Suggestions?

 

Well, your just running a single, with divided turbine inlet. Which side is the wastegate dumping from? I would put it in the side that isn't dumped by wastegate. My twins I had a 3/8in spacer that kinda equalized the pressure then entered into turbine inlet. So an almost common/equal pressure. I just used stainless steel tubing 1/4 (can't remember exactly) I think and about 4 feet of coils away from anything that can burn. I was bored at work one day and just did temporary. Gates does sell guages, but they aren't cheap ones. Autometer is a decent cheap guage. I'm using a 1/2in line from my fass to my injection pump. I have a 1/2 tee then it goes into the VP and my cab. 1/4in stainless. I just borrowed my guages from work for the drive pressure. so I couldn't keep them. I used a 0-100psi guage.

Don't weld the exhaust as it will crack down the road. I would drill rather than weld. If you have a TIG and do some heat treating it should be ok. TIG have less heat than a mig and its more concentrated heat. Its been almost 17 years since I ran one. I had my ATS manifold drilled 1/4 NPT at work on both side of the turbine flange. I think that I rambling

 

0-60 psi for fuel guage and 0-100 psi on drive pressure.

 

If I may hijack, what is this drive pressure you guys keep talking about, and why do you guys always talk about it? I'm guessing its important for something ??

 

Yup its the energy that drives the turbine to compress the air for the engine. Everyone has their secerts on tuning thier ride. Some use the 1 to 1 ratio to measure turbo performance. Usually at when the drive pressure exceeds the compressor pressure you start to push more fuel than run at the perfect combustion ratio. Gasers try to run 12:1, diesel is higher number, but on dyno days we just black everything out. This is just rumor, and I heard this on a street corner.

http://www.turbobygarrett.com/turbob...o_tech101.html

 

Steve, you can pick up stewart warner guages off of ebay for cheap cheap

 

Cool link, thanks . So if I got this right, which is highly doubtable, boost would sort of be equivalent to point #1 on that diagram in the link, the drive pressure would be measured at point #2, and compressor pressure should be #6, and #7 would be about atmospheric....? So drive pressure is kinda like a secret gauge that everybody talks about anyways ?

 

Yup. The turbo is only efficient in a certain range. If the drive pressure gets too high, as Mike said, the engine can't scavenge or get a clean air charge. If the intake valve opens with 50 psi boost and the residual exhaust gas pressure was 65 psi,then the cylinder doesn't get a nice clean charge of air. I hope that makes sense. So if the ratio is 1:1, the boost and exhaust charge are equal and the engine can breathe.

Thats where you see everyone complain when they get an aftermarket turbo that it doesn't make as much boost.. No, but the flow is higher, so lower EGT. I think I am rambling now too...

 

Ahhh, so boost/exhaust should be about 1:1. Hmmmm interesting read but I'm afraid I'm going to have to go back and check my diesel book to read some stuff again - I will have to be zen about it and think about it some more.... like Stephen Hawking imagining the universe in X dimensions.

In any case, I have def. notice MUCH lower EGTs with the Silverbullet - I can barely break 1000 where before if I was not careful it would sail past 1600, both at about 42 psi. Yay, Ideal Gas Law.

 

Actually, I think it is XI dimensions.

High drive:boost ratios on engines with large amounts of overlap on the cam act as an internal EGR system. Typically, turbo engines have little amount of overlap, so the drive pressure ratio doesn't stifle the engine nearly as much.

If you look at compressor maps for turbos, you will see there is effeciency islands. The higher up/further to the right, you are generally much less effecient than lower down/left. This heats up the air more, but also increases the power requirements to turn it. Turbines run off of pressure and heat, so in order to increase shaft power, you either have to increase the pressure, heat, or both. Even though our engines don't have large amounts of overlap, they still do have some, which will back feed exhaust into the cylinder. The HX35's, after about 25 psi on the compressor, the drive pressures really start to climb. You might be looking at 2:1 with it, which at 40 psi on the intake side, would be 80 psi on the exhaust. Thats a good amount of volume that could have contained fresh air.


Steve, you'll want atleast a 60 psi gauge for you fuel pressure. I have seen mine past 50 psi before. I'm running a 100 psi autometer for mine. Can be read quickly, and because its electric, doesn't have the vibrating needle like the mechanicals. Its not cheap though. If you can get a fluid filled gauge with a snubber built into it would be best.

 

So the drive pressure guage needs to go PRE turbo? I drilled my manifold to put my pyro pre turbo. So I should drill the other channel of my siamesed exhaust man. outlet for the drive press.?
I have no wastegate Mike.

 

ram4by that should work good.

The trick is to get as much air and fuel into the cylinder by what ever means possible. Then turn the fuel into heat efficent fashion. You could write a doctorite on the diesel engine combustion. You can push the rules to work in your favor as rules are meant to be broken or bent. Nos and methanol.

Big duration cam hurt spool-up as you have to valve opening longer and takes more (into/out) air to pressurize the cylinder. Helps with cylinder scangening and gets rid of the nasty post burnt combustion. Lots of nox and CO, so OEM don't do that and try to burn the fuel with more to help with emmissions. This explains the drop in boost that you typically see when you put a larger cam.

Intake boost pressure is just a resistance to the air flowing into the motor.

 

If you put the pressure gauge after the turbo, you will basically be seeing atmospheric pressure, which would be 0 on the gauge. Put it in the manifold.

 

I've got a few spare glycerin filled guages. my extras are mostly 0-200 and 0-600psi. though. you can have a 0-200 if you want. they're quality guages not cheap junk.

 

Thanks for the offer Luke but the scale is probably a little high for my drive pressure. Unless you happen to run into Tate in the next month and can pass it to him. I may meet up with him in Mac at some point during the summer.

Turning to fuel:
whats your thoughts on "how to check fuel pressure on a 12 valve" where they say "The gauge can say boost, air, water, fuel or nothing on it,
they will all work excellent".
Can't the deisel fuel attack rubber and a gauge rated for diesel fuel is required?

And Mike, can a person have too many holes in that ex. manifold? I'm worried making it look like swiss cheeze mike let it crack between holes. Anybody out there have tow holes in the ex. man.?

S.