johnandhissaffy

iTrader: (1)

hi everyone need some help on 24v boa convertion but im lost on what parts i will need the spec i want is
boa engine , t5 gearbox 2wd cosworth axle what other parts will i need only trying to get as much help on parts as i can before i start to strip my sierra of it parts cheers

R4N SS

iTrader: (6)

you might need a diff bellhousing for the T5 mate - not sure but someone on here will know for sure. Im going to use my MT75 box out my my dohc and use the 4x4 bellhousing.

you will obviously need the loom and ecu too

johnandhissaffy

iTrader: (1)

ok at the moment i have type 9 gearbox but with the 2.0 8v dohc engine been told the mt75 5th gear is weak and loads of people change the 5th gear to get more mph and was thinking that with a t5 stronger and will let me go to 160mph what rear axle are you using on your sierra ?

johnandhissaffy

iTrader: (1)

would it be best if i yb my sierra then ?

mk22door

Don't forget the input shaft, and the input shaft and bell housing MUST be from a v6 MT75 box, make sure of that before you buy one off ebay John, there were DOHC 8v 4x4's and of course the Cozzy MT75 4x4's both no good for you.

I reckon the T5 would need a bell housing modification, they are expensive anyway without twatting around with that, be easier and proven enough times to use MT75.

I would write all of this down, as you have asked this a few times now.

johnandhissaffy

iTrader: (1)

so i will need the input shaft from the v6 mt75 gearbox then they bellhousing from the v6 mt75 box then i can get a dohc mt75 gearbox that would work yes ?

Marc sierra

iTrader: (1)

Or get a 2.5 TD gearbox that already has the longer 5th gear. The TD gearbox also has the longer input shaft just like the V6, so then you only need to swap the bell housing over.

I have an original 2wd 2.9 MT75 box in my 24v. It still has the original 5th gear, instead I fitted a 3.36:1 diff. That way the difference between 4th and 5th gear is like it should be. Originally the 2.9 2wd Sierra also had the 3.36:1 diff, it's only the 2.9 4x4 that had the 3.62:1.

BTW, you won't reach 160 mph with a BOA, as it doesn't have enough power. A more realistic speed is 145 to 150 mph.

johnandhissaffy

iTrader: (1)

i see what you mean diesel gearbox seems a good idea as it can handle more torque so id need a scorpio diesel gearbox and a type 9 v6 bellhousing and after a while ill be bored of the N/A i found that twin turbo conversion kit on ebay but gona wait a while to see some more feedback on the manifolds and the aftermarket ecu i was told they would be able to run 2x garrett t34 turbos up to 450-500bhp on standard crank and engine internals only thing that would need modding is the heads and sump for oil pick up and obvo injectors (i really hope im not talking bollox making myself sound like a twat lol )

Ade500

iTrader: (1)

RickWood do a bell housing to mate the t5 to the v6. Do you have a link to the ebay stuff you are looking at ? The standard inlet manifold will not get to 500bhp and 2 x t34 are a bit large for the 24v (read laggy)

johnandhissaffy

iTrader: (1)

this is what i was looking at
http://www.ebay.co.uk/itm/1906349522...9#ht_701wt_932

Marc sierra

iTrader: (1)

The 2.5 TD gearbox is also an MT75 and the T9 V6 bellhousing doesn't fit the MT75, you need the front part of the V6 MT75 gearbox to fit the 2.5 TD box.

Two T34's seems a bit much for the 24v and I guess with 2 T34's you'd be able to reach more than 500 bhp as the YB with a T34 can already reach around 380 bhp. The best turbos for around 500 bhp might be something like 2 T25's. But I doubt the 24v will take 500 bhp on standard internals. I don't think the inlet manifold will be the problem. It's said to be restrictive, but then you just increase the boost a bit more to get the air through.

johnandhissaffy

iTrader: (1)

yeah im not looking to turbo it yet just looking into tuning the 24v when i do fit it in i need to do my homework on the turbo side my friend said that a 24v will be a totally different car to my twincam and ill need to learn how it takes corners and braking but he also said its probs better to 24v than yb because at the end of the day its still just a normal sierra so wont hold any money but ill defo do it and start up a thread about it and hopefully get some more advise of you lot as its been very good what u have all said i think the thing i need to do is just stay on 1 option and go 4 it otherwise ill just never start on it as you said there has been loads of people who have done this conversion so it shouldn't be that hard to do

johnandhissaffy

iTrader: (1)

the turbo conversion will be a long way away as goning to be getting used to different power as iv only ever really driving 120bhp lol if that from my twinky but have had a go of a supra with 900+bhp but was only short drive i recon 200bhp wont be much different to what i have now but yh just making sure i dont mess anythink up what rear axle will be best
xr4x4 rear end
2wd cossie
2.0 gls rear end
or use a granada rear ?

4x4sapphire24v

Im currently doin a single large turbo conversion to my 24v. I have had to fit a larger fuel pump, braided fuel lines, 850cc injectors, stage 5 clutch, 2.8 flywheel with spacer from auto gearbox flywheel modified to make the flywheel fit ok, link engine management, proper fuel pressure regulator, modify the fuel rail and new radiator and intercooler combo. Also the boost cannot be raised above 0.5bar boost without melting the pistons. This would mean proper con rods and pistons. Now im being told the mt75 may not take much more than 250 bhp so im maybe need to convert a skyline gearbox or something to get the power to the road.
Just giving you an idea of the work it'll take to turbo your car. There is a serious bit of work involved. If theres anything i can help you with please ask.

johnandhissaffy

iTrader: (1)

oh so the 24v boa bottom end is quite shite then i was told its was really stong someone said it can handle 350+hp std

what will i need to do the conversion at the moment im running a twinky with a t9 gearbox can i use anythink from it at the moment i also have cosworth front brakes 4x4 ones shall i start with the rear axle 1st

4x4sapphire24v

Well i managed to get a 2.9 xr4x4 shell with all the running gear so i used the whole drivetrain and axles out of this. This left me with a 7'' lsd and rear anti roll bar. If ur car is a ghia it should already have the heavier front arb. I would advise trying to get a full car like this as it will give you these parts and also the brakes are a bit bigger 2. This will give you pretty much all the conversion parts apart from the wiring etc. If you get a 4x4 box and a dohc mt75 box just use your rwd front susp and put the bellhousing and input shaft from the 4x4 into the mt75 and this will do rwd. The 24v is strong its just with the turbo compression has to be lowered so im not gona push boost 2 far til i get the bottom end rebuilt. I would def recommend tryin to get a mt75 gearbox 2 as its much stronger.