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Re: Detroit DDEC II People

Reply #25 –
Quote from: Pierce & Gaylie Stewart –


I think Jerrry and I have the only U300 36 footers but perhaps others?

P

Pierce,

Your U300 36' model and mine also have the WTBI floor plan. I believe you could get this layout in a U280 and U300 for '93,'94, and '95.  Hard to find and there can't be many.  When I was looking I saw one '93 36' U280 WTBI and one other '94 36' U300 WTBI.

Jerry 
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Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"

Re: Detroit DDEC II People

Reply #26 –
RRadio, Scott''s 91 is a 36 also
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Detroit DDEC II People

Reply #27 –
for the motorheads, just some food for thought, the 335hp 6v92 intake flows 1200 cfm @ 2100 rpm +/- depending on load (and that is equivalent to your average home HVAC system).  Losses are about the same as added boost (without the heat of compression).  According to some foretravel spec's I found the factory air filter was based on a 10"w.c. clean which is at the end on economic Donaldson's filter scale which starts at 6" and ends at 12". The exhaust side flows about 2900 cfm at the same conditions  as you hot rodders know the first thing you do to make a car "run" is get a big air cleaner, followed by a good exhaust. And that 5" diameter exhaust is flowing at 21,000 fpm (240 mph) at the above conditions. Pumping losses are your enemy when it comes to hp and fuel economy but you already knew that.
15 equivalent feet of straight pipe on the exhaust leads to the following losses @ 2900 cfm
5" dia. 18"w.c.
6" dia. 7"w.c.
7" dia. 3.5"w.c.

oh yeah - the straight tip exhaust outlet is an even bigger losser than whats indicated for the inlet side, slashed straight or slashed elbow is way better, as the OTR trucks use

does the 2 stroke DD rely on the exhaust for "scavenging" ?
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Detroit DDEC II People

Reply #28 –
does the 2 stroke DD rely on the exhaust for "scavenging"

The  2 stroke has a mechanical blower and a turbo that keeps the intake side under constant pressure. When the piston uncovers the intake port openings in the cylinder the pressurized air is pushed into the cylinder just as this happens the exhaust valves open and that pressurized air pushes the spent exhaust gasses out. The exhaust valves close and the piston covers the cylinder inlet port trapping fresh intake air in cylinder.As it travels upward that air is compressed and at the last second the injector sprays fuel into the cylinder and BANG piston moves down, when it uncovers the intake port openings in the cylinder the cycle resumes, hence 2 stroke.
So No  to exhaust scavenging as you would have on a 4 stroke during valve overlap.
From Dieselnet.com

Since one engine cycle in a two-stroke engine is completed in one crankshaft rotation, gas exchange has to occur while the piston is near BDC. There are two important consequences of this:

Since gas exchange commences before and ends after BDC, a portion of the expansion and compression stroke is unusable.
Piston velocity is low during the entire gas exchange phase and is unable to provide a significant pumping effect on the cylinder charge. Hence, gas exchange can only occur when the intake pressure is sufficiently higher than the exhaust pressure to allow the incoming fresh charge to displace the burned gas in the time available. This process of simultaneously purging exhaust gas from the previous cycle and filling the cylinder with fresh charge for a new cycle is referred to as scavenging. To ensure adequate scavenging, two-stroke engines must be equipped with some form of intake air compression and the intake and exhaust ports and/or valves must be open simultaneously for a sufficient period of time.
Both valves in the cylinder head and ports in the cylinder liner are applied as gas exchange control elements. In the case of ports, the piston also assumes the function of a control slide.

Scavenging in two-stroke engines is performed mainly by one of three methods:

Cross-scavenging
Loop-scavenging
Uniflow-scavenging
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Detroit DDEC II People

Reply #29 –
That's why the 2-cycles have a huge air filter and a 5 inch exhaust. They use twice as much air. All of our engines have a maximum w.c. restriction. Good to buy a gauge with the numbers written on the side and be aware what your engine manufacture recommends. Unless you have an unlimited bank account, don't even think about fitting a K&N filter!!!

No, an entirely different engine from the motorcycle 2 cycles with custom expansion chamber exhaust. Andy has a short resonator on his and reports increased power. We live in the mountains with all up hill or down hill so don't want to provoke the neighbors as I keep the Jake on all the time. Stock exhaust is pretty discreet. Some Detroit owners install a switch with resistor to trick the DDEC II into thinking it has 2 psi boost from a stop sign. Much better acceleration off the line but perhaps a little black smoke too. Helps with the tall first gear ratio in the four speed Allison.

Stump has it in his post!

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Detroit DDEC II People

Reply #30 –
Quote from: stump –
RRadio, Scott''s 91 is a 36 also

Stump,

If I'm not mistaken, the 36' wide body (102") came out in '92.  I haven't seen a 36' WTBI for that year.  I believe the extra 6" in width allows for the side radiator for the big Detroit. 

Also, with 2 pocket doors between the kitchen and bedroom there is more room for the bigger walk-thru bath which Cindy insisted upon!  I was lucky to find one close to me in Alabama like Pierce's U300.   

Jerry
The selected media item is not currently available.
Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"

Re: Detroit DDEC II People

Reply #31 –
Oh I thought yall were just asking who had 36' GV. My Bad.
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Detroit DDEC II People

Reply #32 –
Jerry is correct, we have a 92u300 40 foot and it was the one of the first 102wide . Was there 25th anniversary model.the special one had slanted windows. Our does not. ^.^d
Andy & Eileen
MONTROSE COLORADO
1992 U300  40' 6V92 TA
2016 4 Runner
1998 Jeep Grand cherokee

1998 Jeep Grand Cherokee) Build # 4135 Skp# 122921
 

Re: Detroit DDEC II People

Reply #33 –
My fault in the mixup entirely as I didn't include 102" width in the 36 foot length.

P
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)