| Author |
Message |
Larry Baird (Airhog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 2:13 am: | |
The new motor (8V71T)is going back on the dyno with the jakes and new injectors so what should the max rpm set at? It made 380 HP at 2100 with the first setup when we broke it in, now we changed the injectors and installed the Jakes, so one final tune up then in it goes. I have 24.5s on and an RTO so 2300 would be 101 MPH, Hot Damm this old dog will be cooking! What would be a good RPM to set it at, 2100? I added two extra radiators in side the side doors with electric fans to help with the cooling, all spin on filters and a dry air filter. |
RJ Long (Rjlong)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 2:37 am: | |
DDA recommends 2150 no-load, 2100 loaded.
2300 is more fire truck specs. It will shorten the longevity of the motor somewhat, but probably a moot point when talking about RV service as opposed to revenue service.
What size injectors do you have in it now? |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 5:27 am: | |
After 1950rpm the fuel consumption goes out of sight.
If you can cruise at 1950 or less and save the rest for passing trucks uphill , you won't tour Flying J as often.
FAST FRED |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 8:50 am: | |
The 8V92 I had in my Eagle was set at 2300 rpm. Although I seldom ran it this fast, the extra rpm's on upgrades in lower gears was nice to have. Top speed was around 90. I think the speedometer stopped at 80 or 85. I just do not recall for sure.
I think FF has it pretty close. I put 150,000 miles on it with no sign of trouble. I typically cruised at 2000 rpm in the 70 mph range and averaged about 6.5 while towing a Tahoe.
Since I was typically doing cross country trips most of the miles was on the Interstates and I generally pushed it as hard as I could without getting a ticket. |
Larry Baird (Airhog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 11:15 am: | |
Everything is new and stock in this engine, the injectors are 75. I had put new 75s in the N engine I took out when it had an inframe a few years ago and we are putting them in the new engine. |
RJ Long (Rjlong)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 11:25 am: | |
Larry -
According to the DDA literature I have, N-75s are stock in the 8V71T engine. This brochure specs the engine as 350 hp @ 2100 rpm, with 990 ft/lbs of torque.
If this was an 8V71TA, then the specs say 7C75 injectors, 370 hp @ 2100 rpm and 1064 ft/lbs torque.
Sounds to me like whoever did the rebuild on this engine knows what they're doing! Please share who it is - good DDA techs on these old two-strokes are getting harder to find!! |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 3:06 pm: | |
I find the 380 HP hard to believe unless you are running really big injectors, which you don't want to do with that engine. Stick with N-75's for 350 HP at the flywheel, RPM's should be set at 2250-2300 no load to give you 350 HP @ 2100 RPM's (full load).
--Geoff
'82 RTS AZ |
Larry Baird (Airhog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 3:18 pm: | |
I will check the injectors that we took out to see what the size is and we did this at the college I teach at in orange county, CA. |
Larry Baird (Airhog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 4:26 pm: | |
I was wrong, it made 374 hp dead stick under load but with the correct injectors it will be 350 @ 2100 under load and 2250 high idle. I will get a print out when they run it this time. |
Johnny
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 13, 2005 - 12:43 am: | |
I've seen an 8V71 (GMC general semi tractor) cranking out 450+HP...it can be done.
Of course, it also had the governor turned to 2600, and could shoot 4' flames out the stacks.
(I have to go on the record as saying this doesn't sound like a good idea.) |