Thread: Quote to tweak 300tdi fuel pump...can someone explain this to me please

Some good info there Geoff, seems the larger compressor wheel on the VNT gave you the air flow you needed without superheating the air then?

If i can work out how to post a photo I'll put one up of the set up. while the VNT is a smaller frame (GT22) both the turbine and compressor wheel are quite a bit larger.

You can help keep the EGTs in check with a little timing advance, it also helps to keep smoke levels in check. The issue with advancing the static timing is you lose low range torque which is where a Dynamic Timing Advance Spacer kit comes in allowing you the best of both worlds

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Yes agreed. the simplest way I could explain it is, that with almost all tweeks you gain in one area but it costs elsewhere. I didn't want to compromise reliability but it cost more than the average dyno tune.

You did well to get your charge air that cool tbh!

Thanks

Originally Posted by simmo

i) good intercooler- allisport, APT etc,


ii) tune up the fuel pump as described in the pdf, see attached ; Full credit to Ian Peterson, and watch your EGTs careful not to over fuel.

I did it progressively, make an adjustment drive for a couple of weeks , then come back and make another adjustment, record your adjustments.

iii) you can increase your boost up to 18-20 psi, measured at the manifold, not at the turbo outlet.

this will give the best improvements for not much money IMV.

if you want to progress further you probably need to fit a better turbo, garrett VNT etc.

I removed my center muffler, but didn't notice anything performance or noise wise.

I'm running; adjusted fuel pump, APT intercooler, silicon hoses, garrett 2256 VNT, set to 20 psi max boost, no center muffler.

the car is much more driveable, cruising economy is improved, EGTs are lower.

The Tdi is a great little engine, and can give reasonable performance, (just), if tuned up. I found it a bit of a pain to drive before I did some tuning.

good luck,

cheers simmo

I wanted to simply improve fuel economy and as another member has said "improve the flow to improve the go" On my TD5 I only removed the centre box it made NO difference, but on my 300tdi I replaced the whole system with stainless sports system, wider bore and rear box only. So I am totally with you and your experience with removing your center box.

It is not really any louder but the performance difference is immediately noticeable. I have made absolutely no other mods at all as it really didn't seem necessary and, yes, it is more economical under normal driving. So if all you want to do is to great rid of the usual 300tdi bogging down when you start off and then smoother, more responsive running with a tad more acceleration and torque, then change the exhaust for a wider bore and less resistance. It helps the turbo spool up quicker so the whole engine breathes easier. It feels like a cam change for a "high torque" cam in a petrol engine. If I really wanted to go further I would change the intercooler for one off a P38 and THEN I might look at altering the fuelling, but more fuel in usually means more money out of your pocket, unless you can find another way to balance the equation!

I found the std intercooler restrictive.

when I pt my foot down and the turbo was winding up, it would "clock" the boost gauge quickly. ( the boost gauge was still on the turbo out let at that time) .

When I put the APT intercooler on the engine was more responsive, and the gauge took longer reach the full scale.

cheers simmo

i have no mufflers in mine wouldnt recommend it. i removed rear 1st no difference removed center muffler and it loud as a p plater with a patrol

Originally Posted by Pub247

i have no mufflers in mine wouldnt recommend it. i removed rear 1st no difference removed center muffler and it loud as a p plater with a patrol

Did you reinstate the rear one?

Nah was already gone with the scrap bin would have otherwise

Originally Posted by Pub247

Nah was already gone with the scrap bin would have otherwise

Yeah well that makes the difference. My old 300tdi disco had the centre removed and was fine noise wise, definitely no louder than my 4bd1 rangie with centre muffler and resonator up back.

Originally Posted by Stanleysteamer

I wanted to simply improve fuel economy and as another member has said "improve the flow to improve the go" On my TD5 I only removed the centre box it made NO difference, but on my 300tdi I replaced the whole system with stainless sports system, wider bore and rear box only. So I am totally with you and your experience with removing your center box.

It is not really any louder but the performance difference is immediately noticeable. I have made absolutely no other mods at all as it really didn't seem necessary and, yes, it is more economical under normal driving. So if all you want to do is to great rid of the usual 300tdi bogging down when you start off and then smoother, more responsive running with a tad more acceleration and torque, then change the exhaust for a wider bore and less resistance. It helps the turbo spool up quicker so the whole engine breathes easier. It feels like a cam change for a "high torque" cam in a petrol engine. If I really wanted to go further I would change the intercooler for one off a P38 and THEN I might look at altering the fuelling, but more fuel in usually means more money out of your pocket, unless you can find another way to balance the equation!

See this is all I really want to do after all this discussion...I just want to do mods like this that aren't too drastic but that help the motor breathe better.

Looking through previous owner's receipts last night and apparently I've got a free flow exhaust in it, but not sure how good they are. My last mechanic, whom I trust, said all he'd do is put a 3" exhaust in it which would help so it sounds like I should do something like you said about a wider bore exhaust and a rear box only.

Also found receipts for an "intercooler kit" but I think this may have just been silicon hoses...although it was a few hundred bucks back in the day (about ten years ago) and if I sneak a peak at my intercooler it looks very shiny and new compared to the rest of the car so it may have been replaced with something better but I don't know.

As for the tuning, I know that the injector pump was messed with once upon a time but I think it was done right and it's been left alone at least as long as I've had it for the past 8 years without any problems. The main fuel screw got increased by a bees dick recently which I backed off a sniff but it's still a little more than it was. I'd just like a good overall tune to make sure that fuel screw and the pump and everything related to the tune is top notch and safe. I think I'm done with wanting to tweak it up to overperform, although with the turbo I know it's probably getting old so maybe a new shiny (maybe improved billet wheel) version of what I've already got might help a bit...did I just contradict myself?