Offroad-Express

Can anyone out there explain to me any differences between the injectors between rd28/td27/td42?

I've just started wondering if there could be a performance upgrade in using injectors out of a td42 or td27 to put into my rd28.

Now It may be that they are physically different and won't swap which is fine, that would stop my investigation.

My theory works that each rd28 cylinder is about 465cc, whereas a td42 is 700cc, td27 675cc.
Soooo- in theory a td42 injector would be bigger to supply more fuel? Or is it just the injector pump itself that changes this?

Any diesel tech guru's out there able to shed some knowledge on subject for me?

unless your pushing seriously big power i wouldn't bother changing injectors. fairly hard to require more flow than the stock injectors.
tuning pump will do a lot more.

tweake wrote:unless your pushing seriously big power i wouldn't bother changing injectors. fairly hard to require more flow than the stock injectors.
tuning pump will do a lot more.

Have to agree with tweake. remember diesels are opposites to petrols when looking for performance increases. Ie more air not more fuel. So for that fuel increase you'd wanna be running some MASSIVE boost.

I am looking for some big power numbers. Problem I've got at moment is that my injectors are stuffed (big black smoke at mild fueling), so either have to get them recond, or get other injectors. However, I don't really know if there is any difference in the injectors, or how much that effects performance.
Oh, and the engine this is on is a RD28 with a gt28 from a gtir nissan pulsar (I made 260 rwhp with this turbo on my petrol CA18det) I'm (only) getting 5psi out of this setup at moment, but even at this low boost its majorly limited by lack of fuel atomisation. Is there any other reason it would black smoke other than injectors bad? I had to wind fuel screw down lots with it NA to stop it smoking, now its turbo I've got the fuel back up, but it does smoke lots of black still (on boost and off boost- so not just because of lack of aneroid).

Any tips/ advise I'm keen to hear. I've done lots of internet searching for diesel tuning info, so I know a bit, but practice and stuff you learn on internet can be way different

i dont know what im talking about. but do lots of reading on here. Black smoke = unburnt fuel. so the way i see it increase the boost and get more air in there. i remember reading something dieselboy wrote and he said to tune your motor with a boost guage and your eye on the exhaust (or something like that). makes sense to me.

Yea, I would do that (increase boost), but problem now would be how to. My wastegate is a 15psi gate, and isnt even opening. Could it maybe exhaust too small?? It is only 2inch pipe, but I would think that should be ok?

I'm thinking its more my turbo too big (it is a large t28 (.86 ar exhaust)) Or, It's my fueling, (ie not enough fuel) But because Its black fueling so much, I'm thinking injectors not atomising the fuel?

To get an idea of how much black smoke, I dont full noise it if anyones behind me, that would be plain rude and probably block their air filter! Hehe, maybe an exaguratation, but I certainly dont want a police car anywhere behind me....

5psi boost is nothing. i'm guessing turbo to big. T25 sounds like a better size but check with the turbo experts first.

i would just get the injectors reco'ed. unless your pushing 30psi+ theres no need for bigger ones.
i'm told one of the problems with big injectors is it can fire in to much fuel to quickly and it ends up melting pistons. smaller injectors inject the same fuel over a longer time. also with IDI engines it pays to setup precups to suit injectors.
with that much fuel boost comp is mandatory.

you are miles away from worrying about bigger injectors

tweake wrote:
i'm told one of the problems with big injectors is it can fire in to much fuel to quickly and it ends up melting pistons. smaller injectors inject the same fuel over a longer time.

Awesome. This is good to know
From a petrol background its much harder to grasp the dynamics of performance mods for diesel. Sounds like I won't need to worry about changing injectors, I'll just sort the ones I've got.
Hopefully when they better I'll be able to get more boost out of the setup

the turbo your running is way to big.
The guys in oz running t28s on their td42s are only using a .64 hot side for general stuff. for the touring trucks they go upto a .71 hotside but it is laggy. With both these turbos they need to have the pumps modded to flow more fuel to get them to spool up so yeh my guess is you need to go down to a t25.
Diesels don't need to have massive turbos to get big power as they are slow revvers so don't get the flow needed to spin them up. Generally you go for a trubo that would be on a petrol half the size. Ie for a td42 you'd look for a turbo off a 2-2.2ltr car

oh and exhaust wise, I would personally go 2.5"

I might have to search for a smaller turbo. Engine needs a freshen up too, so might just have to put up with it for now until I get my terrano gearbox sorted, then I'll be able spend some more time on the mighty rd28+t