Outer Limits 4x4 Board

now i know this topic has been covered more than once but the search on this site came up with three parts of nothing now i want to turbo my tb42 straight gas not searching for massive power just want more poke planning on gas research carb td42 manifold gu top mount cooler running about 14psi has anyone tried this or have any thoughts on this i also want to keep the price as low as possible not spending my life savings just the kids school funds any help would be great cheers

I aint got one but I do know OnTrack in east kielor have done one. And no doubt JPC have as well.
Search for either of there names should get you there ph numbers or web address.

PM me as i posted heaps on this but its gone. Im in Mt dany too. I will tell you what i know so far and its on the cheep low boost theme too.
cheers brunsy

No offence but 14psi on a petrol motor aint low boost. That would give a massive HP gain. Unless you decompress that baby you will limit its life by a few years.

Cheers, Nik.

You can run up to about 10psi into the tb42 without having to pull it apart. Although decompressing it all you have to do is add a second head gasket

Rob

why would you want to decompress the engine??

Lower compression means you can run higher boost without pinging.

It's generally accepted that you will make more power on a lower compression motor with higher boost, then you will with a high-comp motor and lower boost.

Why? I have no idea. It's just how it works.

The motor becomes peaky, which is not good for 4wd'ing.

I think you would be better off with keeping factory compression and only running 10psi.

Will still haul serious ass when you need it to, and won't be a pig down low.

I realise why people lower compression ratios.

I was just pointing out that the standard compression ratio of 8.3:1 is about as good as it gets.

We have some of our cars running very similar ratios and have run upto 37psi and made 1100hp under the right circumstances.

It depends on the efficiency of the motor and what size turbo you run which designates the amount and temperature of the cylinder pressure the motor can handle without pinging, but personally I would not make it any lower, it would just make it less responsive off boost.

But no doubt, they haul ass with a dryer on the side, especially in low range, you can basically choose any gear you want.


cheers.

You have to be very clear from the start what you want to achieve. I did my apprenticeship at Nizpro in melb so i know a thing or 2 about turbo engines. 5-6psi is about all you want for a stock, well worn engine, this will give a worthwhile gain and not strain the box (auto) or clutch (manual). Since most poeple contemplating this sort of conversion are doing it on the cheep the turbo will most likely be less than textbook perfect, have heard RX-7 rotary turbos work fine. As soon as poeple start talking about lowering compression ratios , its simply NOT neccessary especially on a budget, lucky the TB runs a low static comp anyway. Im happy with my TB on gas around town all i want is some more oomph up top when towing the boat turning 33's. Sure if you want a monster you can spend heaps and build somthing very tuff to swallow 30psi but if you are like me it all comes down to $$$$, By the way a RX-7 13B turbo with wastegate will fit between the block and chassis with an adapter to the stock non-tubo exhaust manifold. Also running only 5psi will enable me to use a completely mechanical boost retard dizzy, sounds simple but still doing my reseach.

I rebuilt my donk less than 15000 ago so with the 8:1 comp i don't see a problem with runnig boost between 12-14 psi i think it would be perfect for turbo setup

Im have an RB30 in mine usually a bad thing in a 2 ton patrol, but that means all the VL turbo bolt on bits make my life easy, so Im going to fit the VL/R31 intake manifold and exhaust manifold, TO3 or GT25 Turbo and Gas Research carb, small top mount cooler and 6-8psi boost should be sweet.....just waiting on a reasonable turbo so I can fit it up.

im running 18 psi in my 4.2 straight gas, runs great and heaps of ball.

if ur not de-comping stay round 5 psi, but if u want more u'll have too

spend a bit more, JPC built mine, cheap to run, specially with that power,

only problem is long trips away, make sure that the country towns u drive

throw, have LPG.

give MARK a call at JPC, good workmenship. he can answer any of ur

questions u may have.

they build most of the turbo trucks in all the comps,