27kw Gain

[powertruck]

Hey guys i just got my truck back from the dyno today after changing my intercooler, i went from running a standard 3.1 bighorn intercooler to a bar/plate type top mount, all they did was take my old intercooler and replace the core, still runing the factory end tanks so everything lines up perfect, WOW what a diff, made 27kw more which i couldnt believe on 8psi, mind u i am not running the factory turbo on mine, am running a vf8 compressor wheel and cover, would definitly recomend this upgrade. Ive also cut out a scoop being a mu they dont come out standard with them

[geeves]

Tell us more? Did the before and after include the scoop and what is the bar and plate type intercooler?

[powertruck]

I had already cut the scoop out on the bonnet prior to fitting the new intercooler, i've made it a decent one so i rams the air down there.
The difference between the intercoolers is that the factory one is a fine/tube type and the new one i have got is bar/plate. must just be in the core design itself, the way they run the tubes through it cools the air to a much greater level, i'll ask the guy who did it for me see if he can shed sum lite. I recomend this upgrade though it makes a huge difference performance wise

[shinz]

Powertruck, this sounds fascinating, I'd be keen to learn more about the intercooler you have, I'd also like some info on your turbo setup, I'm a bit of a greenhorn when it comes to turbos, so what means a vf8 compressor wheel & cover?
As I understand them a small exhaust turbine & big compressor = heaps of low torque & not much top, plus not much lag, the other way around gives a heap of top end power but slow to spool up & slower off the mark. As I said as I understand. ;)Feel free to correct me.
How does what you've got relate to this. What changes to your pump did you make to get the best out of your setup?
Thanks & cheers, Steve.

[Graham]

Where is your 8 psi boost pressure measured from? If it's before the intercooler, then your new bar & plate IC might be less restrictive, giving closer to 8psi boost on the engine side of the IC, whereas the old IC might have caused a big pressure drop. Efficiency is the key to power and gains like this are lovely. Well done. Graham.

[powertruck]

Hey guys truck is still goin great. My boost pressure is measured of the intercooler same spot as the factory bighorn one, i found with the bigger compressor wheel my boost pressure droped slightly but still felt just as grunty as the wheel was capable of flowing more air. The faster the turbo is spinning the hotter the air will be coming out the outlet, thats why when you are matching a turbo to an engine its important you take that into account, otherwise the turbo will be in efficent.
The turbo on my truck is based on the subaru legacy compressor wheel an cover, the exhaust side is still standard well standard turbine wheel anyway, instead of running the 15r exhaust housing im running a 20r which is slightly bigger, this just helps relieve some back pressure which the smaller ones struggle to do. As for lag i didnt notice a thing infact i reckon it helped it out because the engine could breathe alot better. I just run a 2.5" exhaust system the whole way through, exhaust temps never get hot even under load they are still well within the safe zone.
As for the pump its standard, all ive had done is new injector nozzles to freshen them up, apart from that everythin else is standard, oh forgot to mention i have a k'n filter adapted into the standard airbox.

[shinz]

Powertruck, thanks for this, it goes some way to answering my questions, I think. From a bit of google searching, I've figured that the VF8 is basically an IHI rfh5 (?) turbo as is the VICC turbo that the later 3.1s use. what year was your turbo off originally, I'm guessing it was from a later 3.1 as I understand that the earlier ones had a VIAN turbo which is 'sposed to be unrebuildable hence you wouldn't be able to change the inlet turbine to a VF8 one (yes/no?)
What are 15 r & 20 r exhaust housings?
Have you got this on a 2.8 or 3.1? ( sorry fairly new to this forum so p'haps I should already know this ) ;D
Who did your intercooler, how much etc, got any pics?
So many questions, so little time to answer ;D ;D
Thanks though, all info appreciated. Steve.

[powertruck]

Mine is the 3.1 it originally had the rhf5 turbo which got throwen over the shoulder.
The vicc turbo is off the later rodeo's
There is 2 diff sized turbines the earlier turbos 1990 had the smaller shaft were as the later ones 93 up to 96 97 had the bigger shafts which are the better of the 2.
The 15r housing is what they come out with standard all it means is the air ratio size inside the scroll of the housing, the bigger the housing the more gases it can let through but bare in mind it can also create more lag as it slows the exhaust gas speed down. On mine i didnt notice any change at all with lag infact it made it better maybe because it helped get rid of any excess backpressure which the factory housings lacked.

Ive used the subaru vf8 compressor wheel and cover on mind but to get the cover to fit u have to weld an adapter onto the inlet of the compressor becuase the subaru has a 90 degree 2 bolt flang which isnt used on the mu's, the wastegate has to be changed aswell which isnt hard just a matter of re- drilling the holes to line it up.

I'll try get some pics of my intercooler setup,

Jarrad

[shinz]

Jarrad, thanks for that, don't you just hate it when every answer brings a heap more questions? ;D
If the earlier turbo (VIAN?) was an rfh5, then what is the VICC turbo, is it just a later rfh5 or something else?
The 20r exhaust housing you mention, this is part of the turbo, yes? if so what do you get it from, is this part of the VICC turbo? Is the VF8 inlet any good for a front mounted intercooler? I've two reasons for all these questions.
1/ We have a 95 Bighorn which obvously has the earlier turbo (VIAN?) I've read on other forums that they tend to self destruct reasonably early, 80,000-150,000 km & so I'm keen to know where I might go looking for a VICC turbo when & if
2/ I have an ambition to build up a Land Rover hybrid on a Rangie Chassis & with LR panels but with an Isuzu 4JB1T motor & a lot of this info is fairly relevant to them too as I understand, hence my earlier question as to what you have done all this too. Vauxhall/ Opel Fronteras in europe had 4JB1Ts with VICC turbos & front mounted intercoolers for about 113 HP. Thinks, this would be a good way to go
Thanks for the help, its starting to make sense, this whole type of turbo thing is a bit new to me but I'm getting there.
Cheers, Steve.

[powertruck]

the VIAN turbo is of the earlier 2.8 motors, The VICC being the later turbo actually has a smaller turbine wheel but slightly biger exhaust housing,
The turbo we replace all the bighorns 3.1 with when the factory rhf5 packs up is what they call a VI95 its a non bb turbo which can be overhauled where as the rhf5 is a throw away item

hope this helps

[shinz]

Thanks Jarrad, that helps. Seeing as you're in the turbo industry, can you tell us how common are turbo failures in pre '97 (?) 3.1s & at what sort of Kms are you finding them to occur.
Thanks & cheers, Steve

[geeves]

shinz have a look at www.andic.co.nz/
Andy has a similar vehical to your rangi hybrid although he uses a very worked p76 v8

[powertruck]

I think the most 3.1 turbos we have done in a week was 8 lol so that kinda gives u and indication they are pretty common normally around the 100k mark thats when the heatshield in behind the turbine wheel lets go, eventually they will go its just a matter of time

[geeves]

what are the earlier 2.8 ones like for reliability. Mines got 182000 on the clock now and Ive had it since 92000 so its unlikly its been done. It does have a very slight whine at low boost that disapears when the boost goes up ie whine to 5psi good all the way to 13.5 psi I dont know if its been fiddled with

[shinz]

hell, thats a bit scarey, ours is approaching 100,000kms. Is it possible to replace the heat shield & avert trouble, I'm assuming that if the heat shield is no longer effective it fries the bearings? What is the normal fix & what sort of dollars is a joker looking at?
Thanks, Steve.
PS geeves, thanks for the link, interesting & inspirational.

[powertruck]

the earlier 2.8 ones were non bb you can overhaul those ones ok its the 93 onwards ones that are a throw away item. IHI wont release bearing cages for them they try to sell you a complete turbo, from memory a brand new turbo will set you back $1100 thats with new studs bolts and new gasket genuine one.

[mudgrip4]

2.8 turbos appear to last for yonks - rare for them to be replaced. Don't know of any 2.8 owners who have had to do their turbos, whereas general experience with 3.1 turbos is they last between 100 and 140ks, as noted above. Seem to remember someone on this site had experimented with bolting a 2.8 turbo on a 3.1. Can't remember how it worked - perhaps someone else can.

Mike

[justin]

MattMU in perth has a 3.1 motor with a 2.8 turbo on it running through a top mounted intercooler. This was his reason for using the 2.8 turbo as you can rotate the housing to accomodate the intercooler. He has run this for as long as I've known him with no issues. J

[geeves]

I seem to remember from much earlier posts that he got slight improvmen down low Its now pulling hard right from idle but lost some top end. In a 4wd this isnt nessecsarily a bad thing

[namic69]

So how much power and torque at the wheels?