port an polish

[brock hdi]

Bit of a odd one would it be any point in port an polishing the head on a hdi to as I got it off would it make any diff at all ?

[Anton]

You running 200bhp?

[Jimbo]

You running 200bhp?

No need for sarcasm

Im not sure it would make a great deal of difference on a derv
Maybe a small improvement. Wouldnt bother

[cwspellowe]

You running 200bhp?

You say it like you aren't?

---

You running 200bhp?

No need for sarcasm

Im not sure it would make a great deal of difference on a derv
Maybe a small improvement. Wouldnt bother

It WOULD make an improvement.. IF it was a restriction. Unless its a bastardly hard tune it's not really necessary.

[Anton]

Should check post number before being funny. No i'm not Chris, not yet

[samass]

I hear a bag of sand down the inlet will do it nice and cheap

[Dum-Dum]

It'll slow down your air velocity in the port which could cause poor running at low engine speeds as it wont give as good a swirl in the piston bowl which in turn gives good fuel mixing and combustion.

There is however quite a bit that can come off the ports. Shame the valves are too close to eachother to be able to fit bigger ones.

I've had a HDi head professionalaly ported I'll post pics but theres far better things to spend money on.

[brock hdi]

Ok then ill spend cash on geting a better turbo if its going to slow it down then there is no point in doing it

[tigerstyle]

There are some good tuning guides on this site, I'd stick to the 'normal' stage 1 route rather than trying all the expensive things first!
EGR valve
De cat
Back box
Remap
Etc etc...

[Piggy]

all the above as said is almost cost free if you do it yourself...then remap is low cost effective, then FMIC

you can get a lot from a hdi without touching the turbo and head

[brock hdi]

Just done stage1 just picked up a pipe bender to make hard boost pipes for the fmic plus going 2 make 2 half inch exhust do you need a back box on a diesel

[puglove]

No you dont. Get rid of the back box and CAT . Need to leave the mid box for legal/MOT reasons

[Dum-Dum]

You do need a box in the exhaust and at the back would be the better place to have it but the mid box is straight through and the back box is baffled so youll get a better increase by removing the back box compared to removing the mid box.

[brock hdi]

Bugger then better get the mid box back then

[Ruan]

Unless you're north of the 200hp mark, it's going to be vastly fruitless, especially on a standard turbo...

There's a strong likelihood of rather than improving things, simply making it much worse. Unless you know whoever is doing it actually KNOWS their shit about DI Diesel engines, I wouldn't bother taking it anywhere... I don't know of anyone in the UK who I would take a DI Diesel head to who I would trust to improve performance...

[brock hdi]

I'll scrap the port an polish plant then thanks fothe infor

[Poodle]

You can just use any old box thats been gutted for a back box, just needs hangars in the right places. Something of the same design as an hdi midbox would be ideal, but wont make much difference really.

[Dum-Dum]

You can just use any old box thats been gutted for a back box, just needs hangars in the right places. Something of the same design as an hdi midbox would be ideal, but wont make much difference really.

Not true, on a stage 2 car the difference is the best part of 10bhp

[Ruan]

Exhausts IMHO are one of the biggest restrictions on HDis...

Not just the pipe either, everything back to the manifold. The elbow looks like it was designed by Stevie Wonder whilst having a bare mad trip on LSD...

[brock hdi]

So wot best then no box then looking to move on to stage 2 soon

[Ruan]

No boxes will get you pulled eventually, the "slappy" noise from the exhaust is so blatantly obvious of an exhaust with little to no silencing whatsoever...

Get a pipe made from 2.25 or 2.5" with one box at the back to take off the harshness... IMO Don't bother with the stock parts, the bends are so restrictive... Near enough all the stage 2s I've seen with decent exhausts have made more power than the ones using stock parts.

[Dum-Dum]

^^ As Ruan says the standard exhaust is pretty restrictive and pattern replacements are worse.

ideally you want a 2.25" or 2.5" system with a single straight through box at the back.

[brock hdi]

Awww right ill re make my exhaust then out of 2.5 pipe then in to a back box any sort of back box best the best 2 use?

[Dum-Dum]

any back box with a straight through design will be fine.

[Poodle]

10bhp difference between a straight-through box and a straight through box with some perforated pipe in it?!? Impressive, i'll have to experiment with that.

The bends are fine on stock pipes, good and proper mandrel-bent stuff, it's the cheap pattern parts that are the issue. That said you'll be bloody lucky to find an original pipe or even decent after-market replacement on one of these lol.

[Dum-Dum]

10bhp difference between a straight-through box and a straight through box with some perforated pipe in it?!?

Between perforated straight through and the standard baffled back box.

Measured by the scanguage

[Poodle]

You can just use any old box thats been gutted for a back box...

tl;dr?