How Much Boost

[Angus1]

How much boost will my multifuelwith a "D" turbo put up with before it pukes a head gasket or something more catastrophic?

 

[m-35tom]

temp is much more important than boost. mine runs 14 to 15 psi at 1050 f. do not try this without a pyrometer.

 

[Angus1]

I'm workng on the pryo, I was just wondering because it seems like a small turbo I was thinking about a larger trubo and compressor, bit dont want to get carried away. I'm really just looking for a little more on the hills.

 

[gimpyrobb]

Send it to Ken or JWaller, they can increase the efficientcy.

 

[Angus1]

that is my next PM

 

[jwaller]

a said before it's not boost thats a problem it's egts. I run a about 20psi on my deuce but I do it with water injection. without water I can only get about 15-16psi before egts get too high.

remember the intake manifold in the multi is HEATED by coolant and there is no intercooler.. not good for performance but with water injection it can be made a little better.

The multi does NOT like alcohol injection. tried that before I went with water and it is NOT good.

 

[FMJ]

Re: RE: How Much Boost

a said before it's not boost thats a problem it's egts. I run a about 20psi on my deuce but I do it with water injection. without water I can only get about 15-16psi before egts get too high.

remember the intake manifold in the multi is HEATED by coolant and there is no intercooler.. not good for performance but with water injection it can be made a little better.

The multi does NOT like alcohol injection. tried that before I went with water and it is NOT good.

John,

Do you have a guess as to HP with your mods?

Ed

 

[Flea]

For those wanting more power, has anyone considered making a new intake manifold that would separate the water jacket better from the charge air? It seems to me with a little pipe work, one could get the hot coolant away from the intake and do a simple water-air charge cooler on the passenger fender or something.

Just a thought

 

[cranetruck]

Re: RE: How Much Boost

......remember the intake manifold in the multi is HEATED by coolant and there is no intercooler.. not good for performance but with water injection it can be made a little better. ....

This came up before and I couldn't leave it alone, so I installed a couple of thermocouple probes and measured the effect of the water jacketed intake manifold.
Well, the coolant actually cools the air even at a boost of about 10 psi. I measured about 225°F in the intake manifold elbow and 10 to 15° less near #6 cylinder...

 

[Djfreema]

RE: Re: RE: How Much Boost

On my last truck, I had an extra pyromter probe laying around so I installed it in the elbow going into the intake manifold and had it hooked to my Tektronix mutimeter with temperature read out. The air coming out of the turbo was hotter than the coolant temperature. I did the measurements going up the "grapevine" towing another duece in the summer heat.

 

[ken]

I think this would depend on what style head gaskets are in it. From past experence i wouldn't push it more than 15PSI with the old style.

 

[m16ty]

I'm don't know about a mlti-fuel but tractors with coolant running through the intake is to cool the air, not heat it. When the turbo compresses the air it heats it up some and you're also getting heat from the exaust running through the turbo. The cooler you can get air going into the combustion chamber the more fuel you can put to it (cool air is more dense than hot air) and it also helps lower EGTs. I think you could get a bunch of power if someone could figure out a way to cool the air betwwen the turbo and the combution chamber. If you could figure out a way to stuff a intercooler in front of the radiator would be great. You'd probally have to make it look like a A3 though.

 

[cranetruck]

According to the TM, the coolant thru the intake manifold is primarily to heat the air (as jwaller states) at very low op temps, remember the mil spec temp range goes down to -50°F or so and when a coolant heater is used, the coolant will also help the engine start process. However, it also help cool the compressed air at higher boost levels.... acting as an intercooler.

 

[m16ty]

Bjorn, You just gave me an idea. What if you hooked up a independent cooling system to the intake that wasn't connected to the engine cooling system? Maybe to some sort of external heat exchanger with a curculating pump to get the manifold temps cooler. Anybody got any ideas?

 

[m-35tom]

why not just put an intercooler on it??

 

[jwaller]

no need for an inter cooler. 1 simple water injection nozzle and the entire problem is fixed make it smart with a progressive controller and you have a awesome combo(this is what I have and sell for these trucks and it's how I can run high boost +20psi with low egt's(under1100deg)) inter coolers reduce efficiency, increase lag time, and add a lot of complication to a very simple system.

 

[Angus1]

I have a water/meth injection setup on my pickup but I dont think I'll do one for my deuce.

 

[m16ty]

m-35tom, Intercoolers take up alot of room (witch I'm not sure you have on a m35).

jwaller, Since the mulit-fuel engine has a higher compresson ratio than most diesels I'm a little concerned about water injection. Do you think that could be a problem over long term usage?
The only expereince I've had with water injecton is on diesel pulling tractors. You can make BIG hp for short periods ( say 1 pull down a 300' track) but the engines would blow up in less than a mile down the road at that setting. Maybe I'm just going from one extreme to the other. I would like more info on your injection system though .

 

[jwaller]

When my water inj is on I run it all the time when pulling a trailer. I ran run it for 50-60 miles at a time without issue and I've got about 10k miles on the setup so far. I doubt many owners here will ever see that many miles on their truck the entire time they own them.

as you prob know the water evaporates and does not add any additional volume to the mix thus does not change the compression ratio. If the water was not to evap then you might have an issue.

 

[m16ty]

When my water inj is on I run it all the time when pulling a trailer. I ran run it for 50-60 miles at a time without issue and I've got about 10k miles on the setup so far. I doubt many owners here will ever see that many miles on their truck the entire time they own them.

as you prob know the water evaporates and does not add any additional volume to the mix thus does not change the compression ratio. If the water was not to evap then you might have an issue.

How do you keep your EGT under control when the water injection is off? Just keep your foot out of it?