dds92780 Posted August 1, 2012 Share Posted August 1, 2012 Hi guys, i am new to this site but i just spent quite a bit of time reading all the old posts. I used to drive a 87 R686ST with the twin sticks and i loved the reliability of it and the low end power with the top end rpm. What i hated about it though was it only went 62mph max on the highway. Great truck though. So anyways, i got out of the business for awhile and not realizing i shoulld of kept that classic truck and now i drive a 95 RD688S with an eaton 9 speed. It almost seems just about the same speed as my last truck except a slight bit more top end. I am also in need of a new injection pump due to having a slight miss that my mechanic still cant figure out. I got new injector nozzles rebuilt from midwest fuel injection in illinois and it didnt really fix the problem. So im going to take it in to get it worked on in a few months when i have downtime and get a new pump and get it dyno tuned. My question is, what are my options to get more power out of this thing? if i read correctly i only get 1260 tq and 350 hp. and the 350 is at 1800 rpm . similar 350s with vmac or vmacII get 350 at 1400rpm and hold the power and looks like they get better fuel economy. I just want my torque to come on sooner (or boost) so i can get more useable power because the 300 felt more torquey which isnt right. I know on my old truck the puff limiter was removed and i was an expert at driving it and easing into the throttle every shift and then waiting a few seconds to hammer it and it pulled nicely. I read other forums about blixton and people adding that resistor to the pump to up the hp but i saw that its not available for my setup. Any experts out there that can assist me to get more power out of this that have experience with this please help. My final question, i had a mechanic look at my pump and say that one of my washers might be bad and he noticed in his past that replacing the washer would fix a misfire. He opened mine up and saw there were no washers? so im guessing i cant even mess with the pump myself to turn it up? or does it have to be built that way when i get a new one? I just want to get it all done right when i get a new pump. Thanks again Schoger 89 Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
rsb502 Posted August 1, 2012 Share Posted August 1, 2012 with the bosch pump you can really do whatever you want for power, just let your wallet lead the way. I would think going up 10% on your pump with a little more timing and a swap to a wastegated turbo will do what you want. I know that Dale Francis is the man on Mack v8's he has a turbo upgrade for single turbo trucks that almost doubles your boost and you get boost off idle, I would call him and ask what he recommends for an E7 like yours the number is 440-254-4046. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment Share on other sites More sharing options...
dds92780 Posted August 1, 2012 Author Share Posted August 1, 2012 Thank you sir, i will give Dale a call. I just know on my older mack you could shim out the pump or whatever and when i had my pumped looked at, my mechanic told me that some pumps didnt have washers in them and didnt know if we could turn up the pump that easlily and it might have to be done with it off of the truck and getting tested. What do you think about that? i was just looking at diagrams and they made the 300hp r model have 1400 tq at 1100 rpm and my 350 e7 only gets 1260 at 1200 rpm. no wonder its slow Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
dds92780 Posted August 1, 2012 Author Share Posted August 1, 2012 i also notice a few times when i start out in second gear low when im empty it seems to get like a huge turbo boost around 1500 rpm and it doesnt do it any other time. im not sure what that is all about though, but if i could get the truck to run that all day long i would be happier Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
theakerstwo Posted August 2, 2012 Share Posted August 2, 2012 I would not set the timing any more than 4 or 5 degrees faster than specs.Washers may be something he heard another driver talking about.The V mac engine can get 400 HP safe but they have a varable timing device. The mechanical pump is fixed so 400 Hp has to be drove in a safe maner or you still can hurt the engine.If i was to set the fuel up much i would replace the turbo and i would stay with a factory mack 400 for a v mac engine.It is easy to get if you need one on the road.If you go that way i can give you the mack #.Set the fuel up a little at a time till you gain about 6 psi more boost and if you ant go a boost gauge and pryometer then get one first.You will need 5" exhaust also. Quote glenn akers Link to comment Share on other sites More sharing options...
dds92780 Posted August 2, 2012 Author Share Posted August 2, 2012 It just seems that sometimes it has faster boost than at others and i think that could be related to me needed a whole new injection pump. it has a misfire throughout the whole powerband but isnt enough to make it unworkable. it still keeps up with other 350s and gets the job done. we found that cylinder number 6 runs colder than all the others. we replaced all the injectors with rebuilt ones and that didnt fix it. I also lose prime with the fuel overnight and maybe this could be the lack of power hit or miss? I just want the boost to build up faster is all. you think just getting the new pump installed and a dyno run would solve most of that? Also would it help you if i gave you the part number of my pump? Thank you for everyones help so far Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
dds92780 Posted August 2, 2012 Author Share Posted August 2, 2012 The truck is a 95 RD with only 340000 miles and burns no oil or blows any smoke so at least thats good Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
dds92780 Posted August 9, 2012 Author Share Posted August 9, 2012 Bump or to the top of this forum TTT lets see what others might think of this Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
dds92780 Posted August 19, 2012 Author Share Posted August 19, 2012 Anyone else know what i can do to squeeze more power out of this other than a blixton upgrade which isnt even an option for me because its mechanical. Anyone? any older timers that have tinkered with a truck like mine??? 1 Quote Slow and Steady Wins the Race! Link to comment Share on other sites More sharing options...
staxx Posted August 20, 2012 Share Posted August 20, 2012 I would want to fix the engine miss before anything was done, if you took it to a good dealship they could hang a external injector and line off the cylinder that is missing and see if its a problem with the injection pump or in the engine. Quote Link to comment Share on other sites More sharing options...
staxx Posted August 20, 2012 Share Posted August 20, 2012 If the pump has a delivery valve down the have it built at a good pump shop tell them what you want to do most will have no problem bumping it up 10% adjust timing up 3-4 degrees make sure you have no boost leaks check the entire system not just the cooler , then sit back and enjoy the ride. Quote Link to comment Share on other sites More sharing options...
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