| Author |
Message |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 06, 2003 - 8:42 pm: | |
So all along I've been driving my Crown w/ Cummins 220 (743 CID) naturally aspirated, getting 10-11mpg no matter where I go, happy as can be until I get in the mountains. Of course, naturally aspirated engines eat it at altitude (minus 3% HP per thousand feet, minus 1% more HP per ten degrees air temp) and my Crown is no exception... I got real tired of getting passed by loaded cement trucks up in the high deserts
So I just got finished adding a nice altitude-compensation turbo to my motor, and it looks like it's going to work good. It's a wastegated model and I have it set so it won't pressurize my intake manifold more than about 10psi, which every turbo company I talk to says is very safe even without changing compression ratios on my motor.
In the process I purchased one of those little air-filter monitors from John Feld here on the board, installed it, and was surprised to see it peg itself upon simply revving the engine. Gee, I put in a new air filter 5000 miles ago, it shouldn't be clogged *yet*...
So today I bought a new filter element, installed it, and guess what? No difference. This is the stock Crown filter arrangement, and this is happening at no-load, just revving the engine. The filter minder says I'm pulling about 600mm of vacuum in my turbo inlet line when the motor is revved up against the governor....
Now I know that restrictions on an unturbo'd engine (or probably any engine for that matter) equal loss of efficiency, but what I'm wondering is that if my new little turbo keeps the intake manifold at a pressure above sea-level-equivalent all the time, does this restriction really matter? While the little filter monitor is busy pegging itself, my new turbo boost gauge reads about 3-4 PSI...
I'm just looking for opinions here... changing my filter system at this point is gonna be a real mother of a job... if I don't have to I really don't want to...seems like it wouldn't matter considering the engine now had MUCH more air than it did prior to the turbo install....
Cheers
Gary |
Peter Broadribb (Madbrit) (65.37.88.113)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 06, 2003 - 9:00 pm: | |
Gary,
Did you try revving it with the filter removed to see what difference it made to the sensor reading?
Perhaps it needs a bigger bore pipe and a remote filter to allow it to breathe?
What have you done to the exhaust system after the turbo?
Peter. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 07, 2003 - 12:55 am: | |
Hi Peter,
Here's a photo:
http://www.heartmagic.com/turbo1.JPG
I have not tried it with the filter removed.. I'd be game for trying it with the filter entirely disconnected but not with the final paper element removed, because it is one of those multi stage filters that has a bunch of vortex tubes inside that separate most of the heavy dirt by gravity and vortex, prior to going into the paper element. There's enough nasty dust in the thing that running it with no element would be really scary if not downright dangerous to the motor.
The photo pretty much shows the whole system... from the turbo it goes about 3" and hits the exhaust brake. From the brake, another 3" and it's in the muffler. Out of the muffler, it turns around, goes thru the bellows flex coupling, and the final exit is about 5 feet straight back from there, just in front of the rear wheels.
You can see the air filter outlet behind and to the rear of the bellows section, the black hose down there right under the muffler. Everything in and out is 4", and all the paths are fairly short with not too many bends.
Not in the photo ('cause I hadn't installed it yet), my vacuum measurement "filter minder" is ported in right at the bend, right there in front of the orange turbo's output coupling hose, about a foot before the black rubber coupling into the turbo. |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 07, 2003 - 1:03 am: | |
Gary -
Altho I understand your concern about running the engine w/o an air filter, if the area's fairly "clean", I would think that just a couple of minutes to test the airflow w/o the filter wouldn't hurt anything. Early morning seems to be best for "cleanest" air.
Here's a link you might find interesting:
http://www.busconversions.com/newsboard/articles/37134.html
FWIW,
RJ
PD4106-2784
Fresno CA |
Peter Broadribb (Madbrit) (65.37.88.113)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 07, 2003 - 1:46 am: | |
Gary,
Personally I would try it without the air filter assembly, especially if you are concerned about dislodging some dirt from the pre-chambers. This design in itself may not be helping.
I think you may well find that you need a much simpler intake system than was originally installed on your normally aspirated motor. The other thing you should research is the muffler.
A good friend of mine put a turbo on an Isuzu Pup (S-10) and noted his pyrometer was showing very high readings. He called around and was advised to completely remove the muffler and replace it with a piece of straight tube. He did this and the temp went down and the noise level did not go up very much at all.
I had a 440 Dodge class A which was turboed and that ran a 3 1/2" or 4" system and a straight through glasspack style muffler. The turbo actually quietens the exhaust considerably. Of course, the semis with the straight stacks can get quite loud too, so some sort of muffler will probably be needed just for your comfort level.
Have you discussed any of this with any turbo performance experts? I found a turbo rebuilder to be very helpful with ideas and suggestions on what exhaust and intake would work best. At least it was another view to ponder.
Peter. |
Henry R. Bergman, Jr. (Henryofcj) (209.210.116.27)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 07, 2003 - 2:58 pm: | |
Hey Gary, when I was down in Southern California buying my Crown I noticed that the factory turbo Cummins engines had different air cleaners and...
...a larger exhaust pipe diameter that ran all the way to the rear bumper than the NON turboed Cummins Crown I ended up buying.
They also did NOT have any exhaust brakes but had the Jake instead mounted on the heads. I wonder if you could not have a situation where a...
...number of things may be restricting your intake and exhaust system. Yeah, try running your hotrod without any aircleaner at all...
...and see if that helps. Maybe also installing a boost/pyrometer gage may help also to see if the exhaust gas temp is too high/restricted.
Try getting a part number off your stock air cleaner and find out how much CFM capacity the thing has. Also perhaps the muffler for your ...
...application may be the wrong one? Right now I am planning on running just a very large, short, fat, straight through muffler, then ...
...having a large legal spark arrestor after the muffler, then dumping the exhaust out in front of the rear wheels on the drivers side...
...like you have done. Finally, if you have a large enough air cleaner properly installed, maybe you do NOT need the air restriction...
...gage at all since you know already how to service the air cleaner. Maybe the gage for some reason is giving false readings?
You continued energy concerning Crown Super Coaches amazes me. I need to get off my duff. Great pic! Good luck and....CROWNS FOREVER!!! Henry of CJ |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 07, 2003 - 6:32 pm: | |
Took it for a scary test drive today (see my most recent post)
As far as performance, i didn't notice anything other than it doesn't smoke now. That's nice!
. I do have an EGT sensor mounted about 3" from the turbo's exit, and on the whole trip today even pulling hills it never got about 700 degrees f. So I don't think there's a problem there. In fact it worked really well, even the exhaust brake works a little better now.... just the oil mystery of my recent post...
As far as the air filter, muffler, etc, I think what I'm going to do is just wait and see... a long trip coming up next week will tell all when I look at my gas mileage...
Cheers
gary
Cheers
gary |
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