I'm interested in more discussion about the low pop pressure. What makes this happen? What advantage would there be to higher pop pressures? Mileage? How big is the trade off? By that I mean what do you gain in power and what do you have to give up? This goes against what I have been taught to believe about diesels. Why then does the Dmax run 30,000psi in the rail? I'm stupid, smarten me.
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Dyno 2-6-2010 304HP and 525TQ Max
- Thread starter uniquediesel
- Start date
turbonator
Member
"O-ring stud fix"
When we did our build last winter with the ARP headstuds, we used loc-tite into block, with the head bolt holes machined to accept a O-ring, have not opened it up, or noticed coolant loss nor see any indication of coolant seepage on the outside bolts. We regularily boost over 15 psi and have easily cleared 20psi, before de-tuning a bit. With the Holset VGT351 turbo, have never yet saw 1000'F pre-turbo egt's. We use a water injection after 8 psi boost. We were able to remove the intercooler, as did not seem necessary at only 750-800'F, with it.
Still never read John's article, been following his progress since last year when we became members of 5 different sites. Hungry for knowledge we were (and are still learning)..... like lower pop pressures ????
Might just have to invest that $20.00......
When we did our build last winter with the ARP headstuds, we used loc-tite into block, with the head bolt holes machined to accept a O-ring, have not opened it up, or noticed coolant loss nor see any indication of coolant seepage on the outside bolts. We regularily boost over 15 psi and have easily cleared 20psi, before de-tuning a bit. With the Holset VGT351 turbo, have never yet saw 1000'F pre-turbo egt's. We use a water injection after 8 psi boost. We were able to remove the intercooler, as did not seem necessary at only 750-800'F, with it.
Still never read John's article, been following his progress since last year when we became members of 5 different sites. Hungry for knowledge we were (and are still learning)..... like lower pop pressures ????
Might just have to invest that $20.00......
Idi don't need high pressure. It simply won't start hot if you set them to high. I had mine at 5000 psi it seemed smoother but didn't start hot. I currently have drilled injectors set around 1400 psi they are not that great mainly because it was hard to get the pintles to seat after drilling. It seems pretty hard to improve a good stock 6.5 injector.
buddy
Active Member
Getting over 300hp with just diesel is a good accomplishment.
For injectors I would not modify them at all other than pop pressure. I would simply use the stock German Bosch marine nozzles. As for pop pressure, I can see how setting a lower pop may allow a tad bit of more fuel, but I would not do it myself because it can reduce the atomization and quality of combustion. That and you are popping against some high boosted internal cylinder pressures that can exceed 2000psi at TDC. So for a towing rig under constant load you would want higher pop. Many industrial vehicles used closer to 3000psi pops on high torque engines. I think some of the benefit being seen may be from more advance on the injection due to lower pop. On the DS4, the advance can just be programmed in though, and higher fuel rates programmed in.
GM used higher stock pop pressure on turbo trucks vs NA trucks, because they have higher cylinder pressures and higher fuel rates. The more fuel you spit out the better you want the initial fuel atomized to start combusting.
When people have poor mileage and more black smoke and maybe even higher EGTs, they often find several of the injectors have worn and are popping closer to 1000psi. If you can tune the truck to run that way there may be some benefit but I dont think its good for the normal drivers and tow vehicles.
I will always get mine set to higher than stock pop pressures, because I have my truck putting out way more fuel and way more boost than GM intended.
For injectors I would not modify them at all other than pop pressure. I would simply use the stock German Bosch marine nozzles. As for pop pressure, I can see how setting a lower pop may allow a tad bit of more fuel, but I would not do it myself because it can reduce the atomization and quality of combustion. That and you are popping against some high boosted internal cylinder pressures that can exceed 2000psi at TDC. So for a towing rig under constant load you would want higher pop. Many industrial vehicles used closer to 3000psi pops on high torque engines. I think some of the benefit being seen may be from more advance on the injection due to lower pop. On the DS4, the advance can just be programmed in though, and higher fuel rates programmed in.
GM used higher stock pop pressure on turbo trucks vs NA trucks, because they have higher cylinder pressures and higher fuel rates. The more fuel you spit out the better you want the initial fuel atomized to start combusting.
When people have poor mileage and more black smoke and maybe even higher EGTs, they often find several of the injectors have worn and are popping closer to 1000psi. If you can tune the truck to run that way there may be some benefit but I dont think its good for the normal drivers and tow vehicles.
I will always get mine set to higher than stock pop pressures, because I have my truck putting out way more fuel and way more boost than GM intended.
DieselSlug
Well-Known Member
Wow pretty wild.. I need to find a local dyno badd. I want to see what im pushing...
mohawkmike82
Member
Tried several times to get to the build article on this with no luck. Any help?
turbonator
Member
The build is not on this site, it is on "TDP". Will cost a membership to see......we finally bought one.
As has been said in this thread, not a lot of traffic. In the members section, the threads are re-written as magazine style articles. This simplifies reading, as the de-railing of a thread is non- exhistant( always felt this was good idea).
Lots of good info, but this site and others has all the same info. Just need to do the searching, reading, then ask educated questions. Many guys here, were (and are) contributing members of these other forums also.
jim.
great white
Well-Known Member
I've contemplated popping the dough for a membership, it's not that much after all. Mainly to see what info is hidden there behind the "members only wall" more than forums access (which is already free IIRC).
Was it worth the 20 bucks or was it mostly just a different format to thetruckstop?
turbonator
Member
Actually, it was more like $57.00, all said and no not done...LOL. There are some of the older articles that are only available in book and booklet form now, costs about $20.00 (for Americans) a shot for those. All in all, our money is not wasted, as we have read alot of the info already. Although many things we hoped to see are in the book format now though.
Just this week, we received our invite at DP to buy our special membership.....in discussion now(just found another ATT arguement on there this week, i did not realize the controversy this caused until a month ago....:nonod
Just this week, we received our invite at DP to buy our special membership.....in discussion now(just found another ATT arguement on there this week, i did not realize the controversy this caused until a month ago....:nonod