| Author | Message | ||
| christopher l cole sr. (Muziklvr)
Registered Member Username: Muziklvr Post Number: 14 Registered: 7-2006 Posted From: 68.119.228.79 Rating: N/A |
how much would it cost to bump the hp to 300hp-350 hp from stock.JR was saying something about NJT mc-9 having small injectors,not sure,just trying to get a general idea so i can make the best choice for my money when purchasing a bus.thanks for any imput from the bus gods-chris | ||
| Greg Peterson (Gpmci102)
Registered Member Username: Gpmci102 Post Number: 8 Registered: 8-2006 Posted From: 71.228.18.37 Rating: N/A |
I am no bus god but I have invested in buying and reading many of the DD service and info manuals. According to “DA book” if you have a 1987 certified 6v-92ta you can go to 300 HP at 2100rpm and 880 ft-lb of torque with the same injectors. The injectors should be #5234915. You will only need to change the computer program. If you have a DDEC I you should be able to change the EEPROM IC for a different program. This should be very inexpensive and probably you could get it from one of the bus parts suppliers. If you want 350HP you will need to change the injectors and the computer program. You need # 5234775 injectors. This will give you 350hp at 1020 ft-lbs and that is very respectable for any bus. The old setup will probably have a turbo exhaust housing with an A/R 0f 1.08. The A/R is the area of the housing to the radius and determines how fast the turbo will spool up with a given exhaust flow and ultimately how much exhaust can flow at a given backpressure. If you want to go by the book you should change this to an A/R of 1.23. You can get a used turbo housing for $100 to $200 or better if you look hard. Geoff did not change the housing with his non-DDEC engine and had good results but if you want to go by the book you need the A/R 1.23. I would go for 350 HP. Even though it will cost a little more you will have new injectors and the mechanic can set the timing and valve clearance and do what is called a “tune up”. This will get the best performance possible out of the 6v-92. Be sure you get an “old two stroke guy” to do the tune up because even if you read the book some experience is required in order to do it correctly. Good luck and more power is always better and if it doesn’t kill you it will make your bus stronger. | ||
| Brian Brown (Blue_velvet)
Registered Member Username: Blue_velvet Post Number: 370 Registered: 6-2005 Posted From: 67.174.112.202 Rating: N/A |
Christopher, keep in mind that going to a larger injector will usually result in more fuel consumption, but more importantly, more HEAT. MC9s are often plagued with marginal cooling, so you have to be careful with how you squeeze those extra ponies out. I know, because I have a "hot rodded" 8v71 (w/ C65s) that is a de-fuler... black smoke, barely tolerable at altitude. I know the turbo is a different animal, but I'm pretty sure that the injector upsize might lead to heat issues. Just thought I'd throw that in there. And Greg is THE man to give you the data on DDs. Brian Brown 4108-216 Longmont, CO (Message edited by blue_velvet on August 10, 2006) | ||
| Brian Brown (Blue_velvet)
Registered Member Username: Blue_velvet Post Number: 371 Registered: 6-2005 Posted From: 67.174.112.202 Rating: N/A |
oops (Message edited by blue_velvet on August 10, 2006) | ||
| christopher l cole sr. (Muziklvr)
Registered Member Username: Muziklvr Post Number: 15 Registered: 7-2006 Posted From: 68.119.228.79 Rating: N/A |
thanks guys,what kind of fuel milage do you think the stock setup would get with a auto transin a mcv-9,and then avg mpg with the power bumped to 300 hp,which i think is fair power,i still have to keep in mind fuel cost.that's why i'm torn tween the mc9(newer,nicer) or the 4104(a timeless classic that has been completely reworked,wiring ,engine,trans,tires,front/rear caps every thing!)cost of all fuels are on the rise.iknow the 4104 has some advantages,better mpg,35 ft is a plus for close spaces,but that extra 5 ft would be nice for the wife and i to have a very comfy bedroom,and still have room to set the kids up on the other side of the bathroom.either way i go,which ever bus i get,it'll be better than the motorhomes i've been riding since i got rid of my last bus(over 6 yrs ago) thanks-chris...the confused one.... | ||
| JR Lynch (Njt5047)
Registered Member Username: Njt5047 Post Number: 17 Registered: 7-2006 Posted From: 69.132.238.127 Rating: |
You won't have to change the injectors on an NJT 87 DDEC 1 for improved performance. Unlike the "Mechanical Unit Injectors" (MUI), the DDEC can increase injected fuel delivery electronically....to a point. The EEPROM is avail from Luke (US Coach..$120.) and is easy to change out. I have an 87 and have done this mod. Keep in mind that 87 NJTs have several parameters that slow the bus and keep it slow (before modification). NJT redline is 1800 RPM, road speed approx 68 MPH, HP set at 277. Just removing the road speed and redline would make a world of difference. But the HP is increased to above 300 also. Having the redline out allows "spooling" up for hills...which cannot be done with OEM settings. My coach is much better with the new EEPROM. So far no heating problems. I've used the new EEPROM all this summer so it has been suitably tested. When a DDEC 1 hits the road speed limiter, the throttle disconnects...and it won't function until the road speed drops below the limit...this is an unfun situation. DDECs are fly-by-wire so the "disconnect" is electronic. On the injectors...NJT DDEC 1 units can increase the fuel delivery to around 320 -330 HP. This is not the situation with MUI engines. So the 87 DDEC 1 is easier to alter than the older MUIs. This is a recent condtion with the availability of the EEPROM. IMHO you would find the performance of a modified DDEC 1 satisfactory. You will not like the performance of an unmodified transit coach. Also keep in mind that the MUIs can have road speed and red line limits increased by altering the engine gov. This would help and not be too expensive. Best, JR | ||
| JR Lynch (Njt5047)
Registered Member Username: Njt5047 Post Number: 19 Registered: 7-2006 Posted From: 69.132.238.127 Rating: N/A |
All the prattle and I failed to answer your first question...the MC9 will get about 6 or 7 MPG. The GM will get better fuel milage, probably 8 or 9 MPG. Generally a manual trans will get one or two MPG better milage. Driving a manual trans will extract payment aplenty in a different way. Cheers, JR | ||
| christopher l cole sr. (Muziklvr)
Registered Member Username: Muziklvr Post Number: 16 Registered: 7-2006 Posted From: 68.119.228.79 Rating: N/A |
jr thanks for all of the info.i will consider all of your advice in my purchase decision.thank you! chris (muziklvr) | ||
| JR Lynch (Njt5047)
Registered Member Username: Njt5047 Post Number: 22 Registered: 7-2006 Posted From: 69.132.238.127 Rating: N/A |
Good. You very smart guy! Good luck! Best,JR |
