Isuzu turbo diesel tuning guide

[Jack]

Ratios:

	F23WR 	F23SR 	F23SRT
1. 	3,577 	3,577 	3,577
2. 	1,887 	2,022 	2,022
3. 	1,192 	1,348 	1,348
4. 	0,848 	0,977 	0,977
5. 	0,686 	0,809 	0,790
R. 	3,308	 3,308 	3,308

[Jack]

Ratios:

	F18WR

1.	3.58
2.	1.87
3.	1.23
4.	0.92
5.	0.74
R.	3.33

[DutchNovaDiesel]

@Jack, don't forget the FD's

Just googled, and found http://www.opel-infos.de/ yes in german

Here is a nice summary of 5-speed gearboxes: (F10,F12,F13,F15,F16,F17,F18,F20,F23,F25,F35):
http://www.opel-infos.de/getriebe/gf5.html

[Jack]

I know, I couldn't find any.

Nice find!

[santaclaus]

That's some bad ass stuff there , you da man , dutch , - very gratefull mate

its funny i wish i knew some of that before buying the XE fly wheel i have , quite deceiving seeing as the XE has exact same looking bolt pattern , its just not as widely spaced !

In theory if theres potential for fitting the f23 , as dutchnova says -- e.g as fitted to 2.0&2.2DTI & Isuzu 1.7CDTI which = Clutch plate , 228mm in diameter , 14 splines , Ident FP , to fit the following Vauxhall vehicles

Vectra , 96 to 02 , Y20DTH engine used with F23 manual transmission

Astra G and Zafira A , 98 onwards , Y20DTH engine , used with F23 manual transmission

Part No. 9193432
its seems legitimate that Baxter could of fitted the f28 , as it obviously has the same 14 spline input shaft and shares the same size 228mm plate the c20 let does ,- ratios might be a major hurdle as they would be too short , surely ?

-- On another note , i was thinking that , in some regard , that may be it was time between us that we solve the trooper turbo swap myth , as the it has been floating around for what seems like for ever without any substantial evidence ?

Intriguingly , up till now ive always thought it to be akin to Chinese whispers lmao, - after all from what little i know (having not had my one in my hands) , The spec of the trooper is also identical to a little known IHI snail used on mazdas (which i do happen to know the measurements of ) > - and the flange measures = 75mm sq overall - 57mm stud hole to stud hole sq --- 46mm inlet port NOT THE SAME AS THE RHB4 which is 48mm stud hole to stud hole sq -- 35mm inlet port

But it can be understandable why some one would think they are the same , as at a glance it looks like the same square flange we all know , - and it only takes the internet rumour mill to easily perpetuate that it is the same !
Really in all honesty , the trooper is a RHB5 frame turbo , even though it has a substantially smaller turbine housing compared with all the other rhb5 varieties
personally i think it would be unrealistic to assume that they would hang it from our micro sized flange , with its pea shooter of an entry anyway - (even without seeing it) lol

But strangely despite this i was shown the other day some listings of ihi flange gaskets - and interestingly - the square trooper sized flange gasket is listed as for use for > RHF4 - RHB5 - RHF5 -

Im not 100% sure , but if correct , the RHF4 as used in very late model isuzu astras + vectras which superseeded the more common old RHB4 in cavaliers etc , might of had a bigger flanged manifold - which may well allow fittment of the trooper turbo ?
JUST A THOUGHT ?

--------- If none of the above works out theres always a few other alternatives im looking to find out about
other RHF4 turbos ----- subaru legacy RHF4B vf14 ------------- mitisubishi l200 vt10 FHF4H ------------ mazda 6 tdi 143 BHP model RHF4V vj32
none of these have our exhaust flange , but being RHF4'S its possible that if we could find out if they still contain the same diameter turbine wheel as our rhf4 - then the chances are that they could be fitted into our own turbine housing instead ?

[Hacula]

Found some pics of a RHB5 from a trooper 3.1, the housing looks the same as the RHB3 I have lying around.

[eggman]

i had the rhb5 cold side and center on a custom manifold with a 2l diesel hot side and that worked well for me

[Davcohen]

some people on cavweb have done this mod im assuming the lag would be quite bad but would boost quite hard

[eggman]

lag was not bad 3500 started pickin up then full boost (2.4bar) before it got to 4000 and only tailed off at 6750rpm dueto lack of fuel up there

[Hacula]

lag was not bad 3500 started pickin up then full boost (2.4bar) before it got to 4000 and only tailed off at 6750rpm dueto lack of fuel up there

You haven't got any video of that do you? Or some pics? Would love to see it

[DutchNovaDiesel]

I've seen the gaskets for sale on ebay, doesn't say for which car/model etc. they are

The RHB4 & RHF4 as found in the astra/cav/vectra are interchangeable, and have the same flanges on them.
Ihi makes whatever flange the customer wants, so there's a wide variety of flanges on the RHF4's, RHB5's etc.

A combination of turbo's using our exhaust housing might be a nice upgrade, finding a suitable one will need some research !
http://www.coogturbo.com/ihi/RHF4.HTML
http://webshop.turbo.co.nz/index.php?Action=SRC
The RHF4V is a turbo with variable geometry, have seen them for sale but didn't seem like an easy swap.

Following the turbowebshop link, there's a gasket listed for the RHF4-VIBD, found on the 2.8L 4JB1 isuzu:

(strange detail, it says RHF5 on the compressorhousing, but it's actually an RHF4H)

Looks like there was an aircooled oilcooler available on the diesel engine, not in vauxhalls btw:
http://www.isuzone.org/forums/showth...ghlight=diesel

Also noticed Rich's turbo on cavweb: (shame it's not using the VNT)

[Rich C]

Hello, sorry for the delay in coming back. It's taken me this long to get my laptop back off my sister. I've not had much time to read through all the posts, but I get the impression you guys are looking for bigger clutches? I used an XE clutch (228mm diameter?) and had the normal TD flywheel machined flat, then a slight dish (~1-2mm) to copy the flat XE flywheels. The had the clutch centered on the flywheel and drilled and tapped new bolt holes. I still have this at work I think and will ge some pictures if anyone is intersted?
I have a couple more pictures of the turbo setup which I will post up soon.
Yes, it was a shame I didn't get to use the VNT properly, using the external wastegate was a more of a stop gap than an ideal solution, But I never get around to doing anything further with it. Did sound cool though.

[Davcohen]

that looks like a pretty nice turbo upgrade, stupid question here ...... how would that affect the every day driveablilty of the car?

[DutchNovaDiesel]

Bigger clutch, and gearbox options are always interesting...since we're bound to break them !

Here's a nice write-up about IHI turbo's and what the numbers on the exhausthousing stand for:
http://www.mx6.com/forums/1g-faq-for...ssor-maps.html
IHI A/R / 25.4 = A/R on most turbo specs/info sheets

[vxlgsi]

just so you guys are aware if you need a flywheel designed to take a bigger clutch id be happy to help.

[santaclaus]

GOD DAMN IT ! WHY OH WHY , DID WE HAVE TO END UP WITH THESE POXY IHI 'S - i know you can fit any thing to any thing if you so wish to ( god knows ive done it lol ) but its so frustrating to see this engine so limited in easy accessible bolt on options , and a clear up grade path to allow the tuning of this engine to take off !

Christ even being lumbered with the rhb5 we would of been a 100 times better off , as the 5 also most rivals the trusty T3 in terms of hybridising solutions

But no , looks like the Isuzu , is to be forever cast in the misery of limited data , and RHB4 hell for most that dont have the necessary tools to make them selves adaptor plates etc !

-- on a lighter note , he he , finished my pistons yesterday >

22 to 1 down to a intentionally crazy 16 to 1 lol
i worked out ill need 5 psi + 60 cfm of air flow when cranking to raise the effective compression ratio back to the stock figure if im to get the thing started
- got a few ideas brewing , of how im gonna achieve this , but nothing doing as yet

after borrowing a mates big £££ engine analyser pro software , the conclusion is that after a long arduous process data collecting + inputting from a spare engine ......... the stock motor e.g 82hp , 124 lb ft - is making peak cylinder pressure spike of around 2700 psi @ 2400 rpm

stock compression motor with a turbo capable of 140 hp up top but producing 230 lb ft @ a lowly 3200 rpm spiked 4600 psi at that number

my compound turbo set up , stock compression + running 50 psi of boost , equalling around 250 hp + 350 lb ft - crippled the program ( no joke ) it identified multiple calculation errors due to exceeding its calculation table when going beyond a staggering 7000 psi peak cylinder pressure spike ( lol thats diesel torque for ya haha )

same simulation run but with 16 to 1 comp ratio , reduced the mx pcp to what i believe to be a containable 5000 psi ( by containable , i mean , not blowing the head clean out of the earths atmosphere lol ) lmao

the great thing was low compression motor showing small power gains too , due to reduced pumping losses , and a fractional capacity gain
--- i was always told the that , the only reason diesels need such a high comp ratio , is purely down to starting effectiveness , emissions / smoke -
............peak efficiency aka mpg + power is said to around 15 to 1 on a IDI diesel , as established by sir harry Ricardo during the war and also vw in the 70's ----- shame no engine will ever start at 15 to 1 , on its own

[Jack]

Why do diesels need high compression ratios to start? Is it purely due to things not being hot enough to promote combustion at normal temperature?

[santaclaus]

yep thats pretty much the crux of it jack

[Jack]

We need an old-skool John Deere style starting system where leak-off diesel is dripped over an element and sets alight, which nicely warms the air in the manifold up. lmao

[eggman]

i was going to lower my comp to around 16 - 1 too and was trying to work out a system that used a plunger setup in the glow plug hole and for starting the plunger would be down (as if it were a glow plug) and when started (or coming on boost ) the plunger lifts giving u low comp

anybody think of things why it wouldnt work other than how to seal the plunger

[Jack]

Sealing would be your biggest problem.

Why not have a supercharger-type setup for compressing the manifold air? Mega glow-pluggage, mega manifold pressure, then as soon as the engine is running the pressure is used up and everything carries on as normal.

[eggman]

s-charger would need a clutch as it would need to be running super fast at crank speed (300rpm) to make boost dont know the starter would think on a cold day and as soon as it started it would need disengauged or it would be makin about 3 bar of boost at tickover

[Jack]

Nitrous as a starting agent. lmao

[eggman]

what fuel would u use with it remember the high comp (compaired to a petrol) even at 15 - 1 it would det badly and stress the crank unless u used a slow burning fuel like methanol or the likes

[eggman]

and nos have a fast cool effect which would make the starting worse on a derv it would req a spark