:::RHMT::: Real Home Made Turbo
General Category => Forced Induction => Topic started by: t_cel_t on March 12, 2009, 08:00:52 PM
-
my buddy has a 84 tempo diesel that he wants to turbo
its got a mazda rf (2L 2v i4) comp ratio is something like 22.7:1
they made a comprex supercharged version and that has a comp ratio of 21.3:1
the argument we are having is he wants to have custom rods/pistons to bring the ratio down to 21.3:1.
i keep teling him that once any boost starts getting made your dynamic compression ratio goes way past that anyway. if your compressing atm+15psi @21.3:1 isnt your actual ratio closer to like 40:1?
input
-
no one?
-
Just do it.
A stock vw IDI turbo diesel has 23.5:1 compression and I have pushed 40psi + through it without issue. Just adding a turbo I wouldn't expect to pick up much for power though. Unless it is already blowing black, in which case it maybe over fueled enough to make some use of it.
What injection pump is on that motor?
-
Yes a trubo would be good to have on this.
No the comp. ratio would figured : P/Po=(CR)^k pressure ratio of an Isentropic expansion which a desiel cycle use.
Then your final P=Po*(CR)^k where Po is your init. pressure, CR=compression ratio, and k =cp/cv=specific heat ratio= 1.4 (using air b/c the charge is still comprise mostly of air)
Keep in mind that P and Po are expressed in either in psig or Mpa. But stick to either metric or english/SAE do not mix. Both k and CR have no units think about.
If we allow initial Po=14.7psig and P=to solve for, k=1.4, CR=22.7:1 or just 22.7 plug these all in and solve for P. P=1163.5psig final (cylinder pressure).
Now enter your Po=15 psi boost =29.7 psig would make P=2350.7psig final
That would be like running a CR ~37.55:1 :yes:
Hope that helps.
BTW I think that motor can handle as long as you keep fuel supply in mind.
-
its a denso unit i believe, he says he can just turn in the fuel screw
-
its a denso unit i believe, he says he can just turn in the fuel screw
sounds as reliable as a fmu to me
-
its a denso unit i believe, he says he can just turn in the fuel screw
Perfect.
Remember this is a diesel there is no such thing as too lean (well until there is not enough fuel to drive the piston down and it stalls) However too much fuel and things get really hot and you can melt stuff.
-
he also says he doesnt want to go over 140 barr compression pressure because he said it will wear it out too fast
-
egt gauge is your friend, I can make 1550 deg light to light on a 4wd dig. :noel:
-
No the comp. ratio would figured : P/Po=(CR)^k pressure ratio of an Isentropic expansion which a desiel cycle use.
Wow, I've never seen that formula before, and I thought I'd seen quite a bit.
As long as its intercooled & he can add more fuel, it will help. A diesel basicly runs WOT but simply injects less fuel to make less power. If he can increase the oxygen & fuel that gets in the cylinder, he can make more power. It would probably boost low-end more significantly than top-end over NA power, assuming he doesn't use a huge turbo.
-
No the comp. ratio would figured : P/Po=(CR)^k pressure ratio of an Isentropic expansion which a desiel cycle use.
Wow, I've never seen that formula before, and I thought I'd seen quite a bit.
As long as its intercooled & he can add more fuel, it will help. A diesel basicly runs WOT but simply injects less fuel to make less power. If he can increase the oxygen & fuel that gets in the cylinder, he can make more power. It would probably boost low-end more significantly than top-end over NA power, assuming he doesn't use a huge turbo.
Found this in my first thermodynamics book. ;D
-
egt gauge is your friend, I can make 1550 deg light to light on a 4wd dig. :noel:
I need more gauge from light to light, my isspro stops at 1800, and I am at the end... Stupid tiny turbo. :-[
-
A diesel basicly runs WOT
i thought diesels wern't throttled at all?
-
A diesel basicly runs WOT
i thought diesels wern't throttled at all?
thats' what he meant, without a throttle body to close the engine is essentially WOT as far as air flow.
-
Just do it ...
Post ripper vids...
If you can get one with it blowing all kinds of soot and laying a fat snake ... thats GOTTa be front page material .... if we had a front page.
-
give it hell
-
egt gauge is your friend, I can make 1550 deg light to light on a 4wd dig. :noel:
I need more gauge from light to light, my isspro stops at 1800, and I am at the end... Stupid tiny turbo. :-[
I wonder what could have ever happened to your head gasket ???
-
egt gauge is your friend, I can make 1550 deg light to light on a 4wd dig. :noel:
I need more gauge from light to light, my isspro stops at 1800, and I am at the end... Stupid tiny turbo. :-[
I wonder what could have ever happened to your head gasket ???
Yeah that and 70+ psi drivepressures... O-rings and studs should fix it though.
-
A diesel basicly runs WOT
i thought diesels wern't throttled at all?
a diesel engine has no tb body and basically at idle has 600percent more air delivered than needed. Typically diesel engines run lean.
-
Yeah the actual compression ratio of the engine shouldn't have too much to do with turboing it. At least not in the sense that people think of with gas engines (detonation). EGT temps should be monitored.
I think you will need a different type of injector pump too. One that can compensate for boost. otherwise if you turn the fuel up on an N/A pump, I think it will go rich when out of boost, then lean wehn the turbo spools up.
I dont know I'm drunk.
-
yes thats true. see if your pump has an aneroid on it. if so boost feed gets fed to there, basically when boost increases so does fuel.
-
Just do it ...
Post ripper vids...
If you can get one with it blowing all kinds of soot and laying a fat snake ... thats GOTTa be front page material .... if we had a front page.
That would be sick as hell! Make sure you dumb said soot all over xenos front door step
-
should make a noticeable difference, as long as he can turn up the fuel easily.