Im curious about bigger injectors mentioned on this site so have a few questions about them.

What are the benefits of Bigger Injectors in Diesel cars? More BHP, Less Smoke?

I know they give some BHP increase, but how much?

Are they worth the cost since I seem some quite high figures I've seen quoted?

If worth it, do parts exist for the 2.5 TDi lump, and of so how much?

cheers

it's probably not worth it on an a standard engine

Based on recent discussions I've been following, which have also included 'our own' Mr Jason himself - there seems to be little benefit on the PD series engine.

Although it would probably reduce the EGTs a bit due to not having to be 'pumping fuel in' for as long, a lot of people have noticed the car both smokes more AND didn't produce the highest power output.

Now whether that is due to tuners not being too familiar with larger injectors or not, there is a fairly limited set of tuners able to use these injectors properly by the sound of things. On the TDI rather than PDI there was a more notable effect.

I thought about larger injectors but in the end decided not to bother, then got interested again, and I've again come to the same conclusion as before: not worth it.

Propane/LPG fumigation as per Jason's & my car will help a tad IF we can get more air in the cyclinder for the derv to burn AND for some LPG to burn, I reckon Jason will probably push it a fair bit harder than me but it is getting nearer to limits of the engine that are v. difficult to overcome without spending (even more ridiculous amounts) of money

If your 2.5 is TDI rather than PD then yes you can do it if you find suitable injectors, however a remap as is would most likely be cheaper.

i thought the 2.5tdi wasn't a pd engine????

Must admit I don't think it is a PD, more likely a TD so it could be worth investigating. That said, a bigger turbo will probably be a much better investment for the same kinda money IMHO

That was why i asked as i think the 2.5V6 is just a TDI, either way a remap would still be less than injectors

I think to max out the standard PD130/160 injectors you need a turbo like allards VT5. Someone over on Seatcupra.net got 210whp on Awesome's rollers with a 2.0 4x4 tdi PD Audi A3 with a VT5 turbo plus many other things.

My car is the 2.5 V6 TDi. (Non PD) Already have a remap (Custom Code). Somewhere down the line I am looking at a possible Hybrid Turbo (and all the other necessary running gear needed).

Exhaust, Suspension and FMIC are next on my list. (See Auto sig)

I'm just curious more than anything about what the *REAL* benefits are, and if its something worth considering down the line.

an uprated intercooler will probably bring you the most benifits.... to be honest most diesel engines only use about 40-50% of thier fuel dilivery capacaty anyway

Larger flow rate injectors (assuming the pump can put enough fuel out) will give you:

- More BHP

- More smoke

- An inaccurate fuel computer unless the ECU is adjusted to know it is pumping in more fuel.

The extra smoke is due to the engine thinking it is putting a certain amount of fuel in for an amount of air, but actually putting more fuel in.

You can get larger OEM injectors although is your TDi the 150 or 180 variant of the engine. Some company does a different spray patter too to increase the power from a given strokke.

Obviously i would say that if you did go bigger injectors, you would want to do it at the same time as the larger turbo and get the map tweaked to suit. I'd also suggest cleaning out the exhaust paths if you are paying for the engine to have any amount of work done on it.

Any of you fellows got anything for a 1.9 TDi ...larger turbo/injector/intercooler?

TDI will be able to use turbo/injectors/front mounted intercooler for sure, PD based 1.9 I'd stick to hybrid turbo & FMIC, only if you are prepared to spend silly money, injectors

Someone over on Seatcupra.net got 210whp on Awesome's rollers with a 2.0 4x4 tdi PD Audi A3 with a VT5 turbo plus many other things.

And I'm popping up the M5 a bit on Thursday night to go see this car for myself.

And I'm popping up the M5 a bit on Thursday night to go see this car for myself.

followed shortly after a phone call to allard and a turbo and manifold in the post:rofl:

Isnt he close to his targeted 300bhp?

followed shortly after a phone call to allard and a turbo and manifold in the post:rofl:

Isnt he close to his targeted 300bhp?

I'm pretty sure he's pipped that in reality. Bearing in mind he got 280+ at the flywheel without using the NOS, just the propane. It's the NOS kit I'm after actually. Going to find out a bit about how that works compared to the propane. And I think his exhaust gasket was also blowing, and has since been repaired by Allards since Xmas.

Jase, I've fitted Nitrous to a car before - dead simple. Read the skinny on it on tdiclub - you have to use the lowest setting 50bhp otherwise it's bye-bye to the driveshafts!

(Oh and funny things happen if the bottle leaks in the cab at 160kmh - don't ask me how I know hehehe)

Cheers

Bas

But back on topic (and I'd welcome Jase's considered opinion here). Correct me on the following points if I have made an error:

As far as I understand it:

If you fitted larger injectors they have to fire for a shorter time to deliver the same amount of fuel as the OEM ones running for longer. Spray pattern may be better.

Running more boost with a super-hybrid turbo like a VT5 will get more air along with this well-timed fuel delivery increase. Boost can be sky-high on a Compression-detonation type engine, unlike a petrol.

When tuned correctly this should be efficient. A diesel engine is rated by its bhp at a "smoke limit". The amount of fuelling that creates unburnt particles seen as smoke.

If you ignore said smoke limit you can get more hp but with a smoky rear. (Which can be a good thing when used properly hehehe)

Comments Chaps?

Cheers

Bas

There's a nice video somewhere of a diesel dragster in the states. It's got a truck V diesel in it. Looks like a fleet of destroyers laying a smokescreen when it stages and finally goes. Industrial scale polution.

In fact, I found this little site....

Home of the World's First 7 Second Diesel Dragster

J.

There's a nice video somewhere of a diesel dragster in the states. It's got a truck V diesel in it. Looks like a fleet of destroyers laying a smokescreen when it stages and finally goes.

...And there's me saying biodiesel reduces smoke output - maybe it would have been even worse on petrodiesel!

I'd have thought it would be 'slightly' worse - that said, I can't imagine it being much worse :D