dyoung14
Is getting worn out
there is a so called high torque starter nippendso or something like that, but i havent ever had any expierience with them
400HP
- Thread starter zigzkidz
- Start date
there is a so called high torque starter nippendso or something like that, but i havent ever had any expierience with them
Diesel_brad
Dunce
you could have 15-1 compression ratio but you would need to have adjustable timing to get it to fire.
dyoung14
Is getting worn out
what about those modifeied powerstroks um what are the calles stroked out and something else they have a crazy low compression ratio there set up mechanical engines the dont have no adjstable timing they just shoot either into them right?
Diesel JD
Full Access Member
There's a guy (dieseldummy) that is in the GM portion of this site and he's running 18 or 18.5:1 in a 6.2, he says his starts just fine up in the rockies...where it's cold ya know. I've seen Ken's youtube but I also thought something had to be wrong with that truck to cause it to not start in 50*f weather. I'd still plan on always having it plugged in or being able to disable the glow plugs and use white death if need be but it really did not seem RIGHT to me. I can't conceive of why a 6.2 or 6.5 can get away with lower compression and still start normally yet an IDI 6.9 or 7.3 can't.... can someone tell me that?
dyoung14
Is getting worn out
im going to lower the compression on one of my engines one day and i will find out, and if it wont crank by using glow plugs the i will disable them completley and just give her a wiff of either
71cc
Registered User
just for the sake of argument, possibly dabbling in a scientific approach..
. I don't have the numbers at hand, so theoretically speaking here. The ignition point of diesel is 500 degrees or so iirc. The temperature rise of compressing a given volume of air will be predictable. So if someone could calculate the diffrence in degrees it would provide an easier yardstick to gauge combustion by. We all know the higher the ratio, the more work required to compress it, will result in a higher temp gain, but how much are we really talking? Industrial diesel engines are down in the 14:1 range, although they have different injection systems.Glow plugs could still be used in"afterglow" mode to smooth the engine once started. I think static timing is a big factor here. Initial startup will be greatly affected by it.
. I don't have the numbers at hand, so theoretically speaking here. The ignition point of diesel is 500 degrees or so iirc. The temperature rise of compressing a given volume of air will be predictable. So if someone could calculate the diffrence in degrees it would provide an easier yardstick to gauge combustion by. We all know the higher the ratio, the more work required to compress it, will result in a higher temp gain, but how much are we really talking? Industrial diesel engines are down in the 14:1 range, although they have different injection systems.Glow plugs could still be used in"afterglow" mode to smooth the engine once started. I think static timing is a big factor here. Initial startup will be greatly affected by it.
icanfixall
Official GMM hand model
The ignition point of diesel is around 942 degrees... Read all about it in Rudolph Diesels book for a closer temp. If our motors were direct injection we could run a much lower comp ratio and be fine with it but.. Our pistons have the Richardo cups and we have the precup heads. This is the reason for the high comp numbers....
Diesel JD
Full Access Member
Yeah but the 6.5 and 6.2 are also IDI and also have precups. I know Calvin said they were somehow different, I can't remember how, and if it should or would have any effect. Also 18.5:1 is still a mad high CR.
dyoung14
Is getting worn out
they are shorter stroked, but i wouldnt think that would make that much of a difference
zigzkidz
Full Access Member
I havent talked to the guy who wants to do it for a week, but i did email hypermax and they just about told me for get about it. But im not. Does anybody have any input about the idea of twins or compound turbos
Diesel_brad
Dunce
and they would be the ones to ask, being they have more IDI knowledge than prob everyone combined on this forum
ameristar1
The One Blue Thing
Depending on how you want the power to come on, you won't need twins unless that is what you want. A well sized single will do the job. If you want 400hp at the wheels, that is going to be approximately 480 at the crank with a manual trans (20 percent loss), a little over 500hp with an auto.
I did some calculations for airflow and boost requirements using the information off of Garrett Turbos site. To hit the number with low to no smoke, it'll take 69.7 pounds of air per minute and 35.5 pounds of boost (using 3600rpms as a redline, if the redline were raised to 4600rpms the boost requirement drops to 25.5 psi). These calculations are based around the 6.9 versus the 7.3.
The other thing is what to do with the fuel system. This may sound a little nuts, but one guy adapted TWIN DB2s to a GM 6.2 for his Fergie pulling tractor over in Europe (get on the Diesel Page for that one). Runs over 5000rpms with a HX50 and no smoke unless he feels like it. Another option is to get the pump off of a 9.0 liter V8 International, which is an inline P style pump and adapt it to the motor. It might, in the end be the best way to go since you will no longer be limited on the fuel side. The final step is to get a set of 250cc injectors made.
Deep cryotreat everything, balance and blueprint everything, stud it all out. Do a mild Hard Block to the block. Drop the compression and put a cam together that will broaden the powerband. Starters and glowplug systems can be made to compensate, just takes a little sit down time to figure it out.
And if anyone tries to tell you it can't be done, ignore them.
dyoung14
Is getting worn out
exactly you can do anything if you put your mind to it
Well if Ken used his own injectors, atomized diesel likes to light better than a stream.
So, low comp high boost, different cam, lots of mods, for more power and headaches. High compression and low to mid boost for the same power and less headaches, I know which way I would go. The total cylinder pressure is going to be the same either way, yes???
zigzkidz
Full Access Member
I think i could get a DB4 pump and have a little work done to it and that would be good for the injection pump. Now injectors thats different story.
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