EA82T Turbocharger with slightly larger exhaust housing ?

discopotato03 · Post by **discopotato03** » Sun May 11, 2008 10:59 am

Hi all , I was searching through one of my turbocharger supplier sites (OS) and came across a verson of the IHI used no doubt on EA82T's .
I can't remember if it was a VF6 or 7 but they quoted it as having (from memory) a P15 exhaust housing instead of the std P12 one .
I know the cartridge (wheels and center section) are the same because the cartridge number is the same as the VF2 and VF4 .

I'm just wondering if the Turbo Spider Vortex engine used it because if it did that may help explain some of the power difference in their up spec EA82T .

Also I've been asking for a while about some EA82T headers that have a larger hole at the top of the up pipe than others . I'm sure it was mentioned here because someone commented that they had both types and were going to use the smaller one because they thought the higher gas speed would give them earlier spool and better low down torque in an off roader .

Any info muchly appreciated , cheers Adrian .

Subafury · Post by **Subafury** » Sun May 11, 2008 11:05 am

on the uppipe sizes- it doesnt help much but i looked at getting a rex one on there but they seem to be the same ID so i didnt bother. i also talked to a zorst shop guy and he said theres not really much to be gained by increasing the size either.

discopotato03 · Post by **discopotato03** » Sun May 11, 2008 11:28 am

With the headers I was just curious to know if the Turbo Vortex ones were the larger up pipe type . I have a 2WD non Spider turbo header and the 4WD Turbo Spider types but can't get at them ATM .
There have been some good threads at USMB about EA82T headers and let me tell you that L series up pipe is REALLY small internally . It's supposed to be double skinned so smaller inside that they look externally . Someone over there said something like 1" which is pathetic for any 1800 turbo engine .

I've confirmed that the IHI turbos that had the larger turbine (exhaust) housings were VF3's and VF6's and that they were OEM for Subaru .
Itching to get a look at the turbo that came with my Vortex Spider engine and fingers crossed it will be a VF3/VF6 and have the slightly larger header .
It may not be a big improvement but it all helps those who are stuck with factory bits . We will make our own header in time but the best going is the best stop gap isn't it .

Cheers A .

steptoe · Post by **steptoe** » Sun May 11, 2008 12:26 pm

holding my hand up - i got two ID's of up pipe. the id is the flange that turbo sits on 38mm and 44mm comes to mind as being the two measures and I used the smaller in my current application

discopotato03 · Post by **discopotato03** » Sun May 11, 2008 12:53 pm

Steptoe does the up pipe section of the header (41mm one) look any bigger than the other one ?
Also do you know which type of engine it was on originally ie RX or Vortex ?

Cheers Adrian .

Gannon · Post by **Gannon** » Sun May 11, 2008 3:22 pm

I looked into the up-pipe size when i was building my TF035 turbo conversion and decided that as long as it flows smoothly all the way from the heads to turbo, size isnt important.

The difference between the 38 and 44mm up-pipe isnt gonna affect spool up by any noticeable amount (especially when the exhaust entry is larger than the up-pipe)

My advice is make a custom header where the collector to turbo up-pipe is the same diameter as the turbo's exhaust entry flange. Smooth flow is what your after.

discopotato03 · Post by **discopotato03** » Sun May 11, 2008 9:47 pm

Gannon the point of all this is that if the up pipe is larger internally and if there is a VF3 or VF6 with the larger A/R turbine housing to suit then I want them - well the R15 turbine housing and header anyway .

Also no offense but TF035's are really really small compressor and turbine wise . I can only think that Forester GT's are reasonably heavy and Subaru wanted a small turbo to get adequate low down torque from an EJ20 turbo engine .
A turbo that small won't be fussed about a small or slightly larger up pipe because the small turbine housing passage and turbine will be the major restrictions .

Just to rehash the TF035 HM turbine measures 42.5mm inducer and 35mm exducer . The smallest TD04 turbine - TD04 L measures 46.8 by 41.2 and is used in the late 90's on Rex's .
IMO the TF035 is a bit small for an EA82T , even a healthy 4 plug EA82T could use a small TD04 provided the boost pressure is modest .

The golden rule with turbocharging is that its the volume of air being pumped in that makes the power - not the manifold pressure .

Cheers A .

Gannon · Post by **Gannon** » Sun May 11, 2008 10:34 pm

I fully agree that the TF035 is a small turbo, and not all that great for producing high horsepower numbers. But i dont think its out of the question to assume that a power output equal to the GT Forester on an EA82 is out of the question. (with the right supporting mods of course)

The point i was making about the up-pipe i have illustrated below

Its pointless having a 1 1/2" pipe if it feeds into a 2" chamber before it reduces down to the funnel for the turbine

discopotato03 · Post by **discopotato03** » Wed May 14, 2008 6:22 pm

125 Kw equates to 167 Hp and we know that's not difficult to achieve with a mildly modded EA82T .
What holds the EA back is the header/exhaust/cams/Cat/agricultural heads/basic management - and lack of intercooling . The compressor and turbine in the EA's turbo are actually larger than the MHI TF035's .

The std EA82T header damps the exhaust pulses to such a degree that you are forced to use small turbos if you stay with it . The whole idea of making a better header is to allow the engine to breath out and assault the turbos turbine with as sharp an exhaust pulse action as possible to kick the turbine/compressor (rotating assembly) into life .

Take this to the grave , Subaru deliberately muzzled the EA82T engine because turbo torque is dangerous in the hands of Joe average front wheel drive pilot . Every grunty road going FrWD turbo car has been a disaster ie Cordia Laser etc . If they are not toned down they are evil torque steering pigs and known killers on slippery surfaces .

So enter AWD , can get 100% of the vehicles weight on the driving wheels so tractive effort is shared and therefore less on each individual tyre so less likely to lose traction . Then more torque can be unleashed and with usually more predictable results .
Had the L AWD's had the viscous transmission I think they would have been speced with higher output EA82T's - provided they passed emissions legislation .

Foresters can have the twin scroll headers and the BB VF36 fitted and lose no torque anywhere over a TF035 - actually they make more torque and horsepower and are cleaner and use less fuel . It's a prime example of the technology required to make them work properly .

That aside I found out that my 87 Spider turbo engine had a VF5 with the 12R turbine housing so not so good . If it has to go in with a std turbo initially at least it will have the XT4 header in the short term . Will probably have to make the new header with the engine in the car to make sure it clears everything . I'd like a 15R turbine housing if I can lay my hands on one - I suspect the rally turbos had it to get them up to 180 odd ponies with longer period cams and close ratio gearboxes .
Now that I know the part no's of the VF3/VF6 with 15R turbine housings I'll check these against the rally turbos part number .

Cheers A .

Gannon · Post by **Gannon** » Wed May 14, 2008 7:20 pm

If the TF035 is too small, just go a TD04

We all know that a TD04 on the EJ20 can make 200hp in factory form, which is getting towards the upper limits of an EA82 without going for O-ringed headgaskets and proper headstuds.

They are easy to come by cos rexy people chuck them for bigger turbos and they mount almost the same as the stock turbo which allows you to very easily fit a Liberty WAIC or Rexy TMIC

discopotato03 · Post by **discopotato03** » Wed May 14, 2008 10:11 pm

Yes the obvious upgrade is the TD04L-13T-6 but I'm just looking for the IHI housing in the short term if I can find one .

Cheers A .

steptoe · Post by **steptoe** » Thu Aug 04, 2011 6:49 pm

Rushing into this reply while Disco is in the house !!

Finding my 4/87 Vort has a VF4 8703, made in 03/87 ?, car made 04/87 - it is not VF5 like disco has found with his Vortex sourced spider gear.

Also somethng no one else has been too interested in is the diameter of the exhaust inlet under the turbo I have got running in my L Sedan my preferred 35 or 36mm diameter also got it with the Vort so am happy. There are bigger 41mm that deliver boost a bit higher up the rev range? bit weak down low but zings to 6500 in no time with the 41mm ID exhaust turbo inlet.

Gannon · Post by **Gannon** » Thu Aug 04, 2011 7:34 pm

I believe the UK and JDM Vortex's that made 136hp were equipped with a VF7

steptoe · Post by **steptoe** » Thu Aug 04, 2011 10:38 pm

sure we have covered this somewhere but the higher power output is found higher up the revs too, not sure if same torque or better on these 136 jobbies, likely to have the 41mm inlet on the pipe. Bugger HP , I love torque

Think I may have decoded some VF numbers

H-top · Post by **H-top** » Fri Aug 05, 2011 7:15 am

I've got a VF7 at home

H-top · Post by **H-top** » Fri Aug 05, 2011 8:37 am

Need any measurements?

steptoe · Post by **steptoe** » Fri Aug 05, 2011 8:53 am

Disco may be interested. Not sure what you would measure in comparison. Now curious as to the part number stamped into the ID plate cast in it and the rest of the VF7 numbers - should be four more digits as in month and year it was made. Now , also wonder where you got it, what it is off?
Myself have never measured the turbos bits at all, just the outlet of the turbo crossover pipe that the turbo sits on and despite the answers some people theorising with our members have provided I have felt enough difference in the drive character of the 36 and 41mm diameters and know what I want. If I were to grow hairs on my fingers closer towards my fingernails and drive at redline all the time I may want the bigger 41mm hole.
Plase add some figures at least to this oldish post revised:)