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Discussion Starter · #1 · (Edited)
An member was interested in buying a stainless F2T to T3 flange bolt on manifold and a T3 / T3/T4 turbo on ebay, what can he do for a downpipe and do I know of a bolt on solution?

Personally I recommend having a T3 flange welded to a factory F2T manifold over the Ebay stainless T3 manifold, The welds are known to melt, the flanges aren't level and the pipes don't always line up and are sometimes welded crooked.

This got me thinking about what would be the easiest/closest to a bolt on turbo upgrade you could purchase (not fabricate) on a 2.2L turbo F2T car.

Before starting, I would like to clarify that compressor maps, compressor ratings, giant turbos... change nothing when it comes to power to psi ratio, intake manifold pressure that you read on the boost gauge decides everything. 15psi in the intake manifold at 100* F will make the same power if it comes from a turbo rated to flow 21lbs/min or 55lbs/min, there is a small hp variation based on air temp and density depending on how much heat the compressor generates, IHI, Mitsu, kkk turbos tend to have small comp housings and generate more heat during compression than garrett, holset and other turbos.
This heat can be controlled with proper intercooling and water or water meth injection but the cooled air will be more dense (take up less space) and result in a pressure drop, this isn't an issue because we regulate boost based on intake pressure but does mean the turbo has to generate more pressure before cooling and the intercooler has to handle more heat from the turbo.
If boost is dropping near red line because the turbo or turbine housing is to small a larger turbo will make more power in that area by making more psi but wont generate more hp per psi.

Let me state this again 15psi manifold pressure at X degrees F or C makes the same power with a turbo rated for 200hp or a turbo rated for 500hp. So if you want to make more power you have to increase boost or make the intake and engine flow more air volume at the same PSI, I would say the F2/F2t can be made to flow a max of 11% more air through porting and valve work... although that doesn't sound like much in stock 145hp form (about 15hp) the 11% caries to whatever power the engine is making so at 300 hp that's 35.3hp and 400hp that's 44hp...

Option 1:
The easiest and most expensive option.
BNR Supercars installs a GT2860 center section in the factory IHI VJ-11 turbine housing the GT28 is rated for 40lbs/min flow.
They require a VJ-11 core and turbine housing and note "The turbine housing of the VJ11 has a cracking problem if it is extremely high milage or driven hard. If the turbocharger core isn’t usable, we will notify you before the machine work process starts!" Well if it has a tendency to crack with a vj-11 turbo in it that is rated to explode at 21lbs/min how long will it survive after being machined out and running a larger flowing turbo at higher boost?
The price is 1050$ + core and shipping to and from.

The factory turbine housing is restrictive and so is the O2 housing, this will lead to similar spool characteristics of the VJ-11.
This might be the best option for people running air conditioning or with zero mechanical skills.

Option 2:
Someone told me they where having this done:
vj11 rebuild with a 16t compressor by pt turbo (they used to be called performance techniques) in San Bernadino, CA.
This cost 700$

A big 16G compressor has the ability to flow 36lbs/min of air so this is like a T-bird compressor upgrade on steroids, unfortunately the whole assembly will be running the tiny VJ-11 turbo shaft which has a tendency to snap in two.

Option 3:
This is for cars without A/C (sorry pansies, just kidding) but seriously this won't fit with A/C and will require moving the low pressure power steering line and cutting away some of the power steering pump mounting bracket for the downpipe to fit.

To run A/C and upgrade the turbo will require a custom made very tight radius turbine O2 housing/downpipe.

Personally I find this the best option because it sets the F2T up to run T3 and T3/T4 turbos.

Turbo oil and coolant plumbing:

Factory coolant hose size : 3/8"
This will require two 3/8" barbed fittings with male threaded ends, the garret t3's and T3/T4 I have worked with have 1/4" NPT female coolant fittings in the turbo.

Oil supply fitting on pipe:
-Thread pitch 1.0
-Flare angle 45*
-Thread O.D. 0.3895" / 9.895mm (Fraction 25/64")
Closest size = 45* flare M10 X 1.0
So a: male 45* flare m10 x 1.0 to male (thread pitch and size oil inlet the selected turbo runs) adapter will be required.

Oil return hose:
The oil return pipe for the selected turbo must be used.
It may need to be cut if it's long or runs to low for the factory oil return fitting on the block.
If the oil pipe for the turbo is the larger than the factory oil hose, stretch a piece of hose over the factory oil return fitting, install the larger hose over the fitting and hose and clamp it down.
If the pipe is smaller than factory a double ended barb fitting reducer will be required from the size of the new turbo return hose to the size of the factory oil hose.
If the size is the same...

Note: To remove kinks from hose bends, install hose clamps over the kinks and tighten until the hose is round, after a couple weeks the hose will keep its shape and the hose clamps can be removed.


Compressor intercooler hose fittings:

This can not be answered in this post because most turbo compressor inlet and outlet are different sizes and the kind of intercooler pipes (factory or aftermarket) and size varies.
Silicone straight reducers and 90* elbow reducers come in all kinds of size options. Mishimoto are the most affordable silicone couplers I have found.

2.5" intercooler pipe and couplers can be used with the factory intercooler, just install the factory hose over the intercooler fittings and cut it flush with the fitting, install the 2.5" coupler over the factory hose on the intercooler and install T-bolt clamps or find 1 7/8" to 2.5" silicone straight reducers (will require more space) between the intercooler and 2.5" pipes.

The edge of the battery tray next to the upper intercooler fitting will need to be cut away for the 2.5" pipe and clamps to fit there.


Turbo support bracket.

The factory turbo support bracket will sit too high for any upgrade turbine housing to bolt to and the bolt location will be different.
It is easiest to have something welded up to support the turbo, you can remove the factory triangular piece held on by two 10mm bolts and have the support welded to the remaining part of the bracket or :
use 3/16" or 1/4" steel and a propane torch and a vice. Drill two holes in the piece of steel for the 10mm m6 bolts to mount to the factory block bracket. Then the steel must be bent 90* downward then 90* out toward the turbo mounting hole. If the turbine mounting hole is not directly under the turbine or sits at an angle twisting and creative bending of the steel will be required. Use cardboard as a mock up template. Heat the steel with the torch and beat it with a hammer (while in the vice) to bend it.


Waste gate housing/swing valve:

The best option is to find a Saab 5bolt T3 swing valve housing, it will have a 3 stud and beveled lip for the O2 housing/downpipe to mount to (more info on this with the downpipe).
Automotive tire Motor vehicle Automotive fuel system Hood Bumper

The second best option is to buy a 5bolt T3 wastgate swing valve with 2.5" V-band fitting.
Composite material Auto part Metal Nickel Household hardware


O2 housing/Downpipe:

The downpipe that fits the F2, clears the oil pan and lines up in the factory exhaust location is the
Saab 9000 turbo 1986-1998 downpipe
It should look like any of these:

Gas Wood Art Bicycle handlebar Pipe

Wood Gas Metal Composite material Hardwood

Auto part Automotive lighting Gas Nickel Tool

Microphone Automotive lighting Office supplies Gas Auto part

Nickel Gas Metal Auto part Household hardware

Here is one bolted to the turbo:
Motor vehicle Engineering Gas Auto part Machine

The downpipe will require cutting, clamping, stretching or reducing or welding to the exhaust on the car somewhere before the cat.

If a 2.5" V-band wastegate housing is used instead of the saab housing than the downpipe flare and flange must be cut of and the V-band fitting must be welded to the downpipe in a way so it sits in the same position as it does with the saab 3 bolt flange, both the saab flange and V-band flange are clockable 360* so it's where the pipe passes the oil pan and meets the exhaust that matters.


Internal wastegate actuator:
This will require a small bodied adjustable internal wastegate actuator and bracket that fits your T3 or T3/T4 compressor, space between the compressor and block is limited and this is where choosing the turbo wisely is important, if you want a turbo with a huge T4 compressor (huge for a 4 cylinder) capable of flowing 55 lbs/min remember that you will have to run: rough math based on F2 whp- 110 + 30% drivetrain loss = 143 bhp. 55lb/min (1bhp = 1.08lbs/min) = 509 bhp / 143bhp = 3.56 bar atmosphere or 2.56 bar above atmosphere or 37 psi boost. These numbers are generous the lower comp F2T generates slightly less power than the F2 block and I doubt the drivetrain loss is that high, The lower the engine BHP is the more boost must be ran to achieve 55lbs/minute flow..
So unless you are planing on running 37+ psi boost you don't need a turbo rated to flow 55lbs/min, piston compression ratio's don't increase the amount of air getting into the engine and only increase the compression rate of the cylinder volume, increasing the engines volumetric efficiency (VE) and will have a slight increase on power to PSI but to make serious gains more air and fuel must be burned in the engine and lower compression allows for that.

I used to be all about external wastegates but if you look at the two, both internal and external wastegates hold steady boost to redline perfectly, External wastegates are more expensive, require custom installation, welding, pipe, flanges. Internal wategates do not, when you want to change wastegate boost pressure external wastegates require spring changes and combinations of springs that cost money and are limited in PSI increments to achieve desired wastegate boost, internal wastegates require loosening the lock nut and turning the wastegate shaft to change wastegate boost in any increment desired.
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Something tells me that you are a neurodiverse person, if not doesn't matter - but it some how explains the detail of these posts and your highly focused interest. If so I think its great!

7 Posts
Thanks for this detailed post carnage. I have my VJ 11 rebuilt with the 16g compressor wheel assembled and ready to be installed on the car. Haven't had the time to install it in the car.

It'll be controlled by the scg-1 from innovate as you recommended.

I'm going to save this post and get started on the parts required for the t3/t4 swap you've described in detail here for whenever my VJ 11 center shaft decides to call it quits.

I appreciate you taking the time to answer my question.

2,968 Posts
Discussion Starter · #4 ·
Thanks for this detailed post carnage. I have my VJ 11 rebuilt with the 16g compressor wheel assembled and ready to be installed on the car. Haven't had the time to install it in the car.

It'll be controlled by the scg-1 from innovate as you recommended.

I'm going to save this post and get started on the parts required for the t3/t4 swap you've described in detail here for whenever my VJ 11 center shaft decides to call it quits.

I appreciate you taking the time to answer my question.
Are you running a chipped ECU?

I recommend working your way up in boost slowly and keeping your Air fuel ratio at or richer than 11.8 AF under boost, 11.3 near redline. So set Boost cut by A/F's on the SCG-1 properly.

The 16G should breath better and give you more power in the top end but remember that air or exhaust gas flow is the limiting factor. But think of a Honda Civic transmission. Wait what?
The IHI VJ-11 turbo doesn't snap the shaft during boost it snaps the shaft during spool up, the shaft doesn't break due to high rpm speeds it breaks due to sudden torque during spool up trying to get tor high rpm speeds, how do Honda transmissions survive 500+ hp, no sudden torque gains (very little torque at all).

Although intake manifold pressure (PSI) is intake manifold pressure and one turbo won't make more power than another at the same intake manifold PSI, the larger compressor and housing should (Provided the 16G is efficient) yield more PSI per turbine RPM. Meaning the turbo shouldn't have to spin quite as fast to generate the same PSI in the intake manifold.
This should be a bit less sudden load on the turbine shaft when reaching the VJ-11 max ish 15psi.

Once you have your boost adjusted properly, I recommend matching the power / exhaust flow of the stock IHI at 15psi, at what ever PSI the 16G feels as fast as the vj-11 did at 4500rpm your probably flowing the same amount of air/exhaust. Don't forget to set you SCG-1 boost cut by pressure failsafe.
At this point you must make sure the fuel system and control is up to the task of moving further. Thanks to the SCG-1 A/F boost cut failsafe you don't risk your engine finding this out.
Using the SCG-1 boost gain settings you can set up progressive boost control allowing the turbo so spool to a safe psi and gradually build boost to redline in a less dangerous way for the turbo shaft, allowing for more boost on the VJ-11 or RHB5 hybrid turbo than they can handle on straight, peak spool. This will also lighten the sudden torque load on the transmission when running above "15psi" torque range.

My friend ran the SCG-1 on his 6cylinder BMW running 20psi and a bunch of upgrades, he says it saved his motor many times over. The SCG-1 paid for itself more than 10X fold every time is saved his motor.

Remember if you want to shift at redline (6250rpm) set-the SCG-1 shift light at 6000rpm and see if you react to it fast enough to avoid factory RPM cut, but where you shift in the RPM doesn't matter as long as your in the rpm's power zone in the next gear.

7 Posts
Are you running a chipped ECU?
I ordered the probinator and zombie chips from ebay and intend on installing one when I muster up the courage and time to get it done.
I don't know if there's any actual difference between the two other than the obvious fuel cut for overboost that both eliminate.

Do you know if they do anything else? is fuel trim or timing or anything else affected by these chips?

2,968 Posts
Discussion Starter · #6 ·
Probinator chip is a good chip, that's what came in the rusty 626GT and ran up to 30psi (on water/meth) without timing issues. 21psi on premium gas without issues.
Zombie SS chip is okay for factory turbo at and bellow 15psi but has an advanced timing curve over factory, even on the VJ-11 at 15psi the exhaust manifold and turbine housing turn glow in the dark red. The Zombie chip will cause engine failure when used with high powered applications, perhaps with water meth the added timing can be controlled from 15 -21psi, but why bother.

No red manifold with the Probinator chip at 21 or 30 psi.

The Zombie chip was tuned on a dyno for a specific car to get the most power out of the set-up that was on the car, the turbo was a factory VJ-11 and mods where bolt on available at the time (not very modded), the car was an Aspec F2T rated for 87octane and running premium 91 or 93. The tuning shop squeezed a couple hp out of the engine by advancing the ignition timing (which was their job) but that closed the window for running the chip on larger turbo, higher boost application where timing needs to be backed off.

Because the F2T factory timing is conservative 21psi can be safely achieved on it.
With the Zombie chip timing advance I have noticed leaner air /fuel ratio's on factory set-ups that I have with all the other chips available and much bigger mods.
This is because of the Vain airflow meter, it controls fuel delivery based on airflow, the maps are fixed (they don't chase air fuel ratio voltages above 3000rpm) so at x atmospheric pressure, at X degrees F*, at X air flow meter flap travel, the injectors deliver X amount of fuel. Port the head, the intake, upgrade the throttle body, get bigger valves, larger intercooler and pipes, better exhaust, manifold turbo... these will all require more air and the flap in the air flow meter will open more and the injectors will deliver more fuel proportionately and Air Fuel ratio's will stay the same until the injector duty cycle limit is reached or the flap in the airflow meter is pined opened.
But when advancing the timing you make more power on the same amount of air by generating more heat which results in less cylinder cooling effect from the fuel, earlier spark means more gas air burn time, higher exhaust gas temperatures and leaner air fuel ratio's.
So adjusting the timing curve leaves the fuel trim the same but moves the air fuel ratio curve leaner.

With the Zombie chip you get a couple extra hp and timing that is close to dangerous for the engine on stock fuel maps at 15psi on a factory turbo.
With the Probinator chip you get the power available from running 6psi over 15, while maintaining proper A/F until the injectors are maxed out and piggyback fuel control kicks in, with lower EGT's than the Zombie chip at much lower boost.

They say only a small timing advance was added to the zombie chip, well whatever it is they added is greater than the effect factory timing has on 21psi boost, I don't know how much boost factory timing will allow for and I don't know how much boost above 21 would be required to turn the manifold and turbine housing red due to over advance timing for the cylinder pressure but I do know running the Zombie chip at 15psi puts you much closer to that point than running 21psi on factory timing.

With a knock controller/detector/boost cut fail safe finding the boost limits of factory timing would be possible. After running 21psi set boost on F2T's for 17 years I know it's safe and never wanted to push my luck going any further. Then I read that with water meth you must advance timing but I had timing I could not back off above a certain boost (hand meet glove).

I the case of my build I have added an old MSD piggy back timing controller to pull a bit of timing at 30psi just to be on the safe side however increasing the amount of water/meth injected in the engine at 30psi would prevent detonation and pre ignition even more allowing for more timing advance (which I can't achieve) = a bigger safety window.

I know your wondering if you can run 21 psi on the factory ECU and 30psi with water meth why would anyone need stand alone engine management for an F2T. I would say for better cruising gas mileage at and above 3000rpm when not boosting, for revving past 6250rpm, to have boost cut during knock detection (factory F2T has this but it's tied in with rpm boost control and must be removed) and other modern failsafes the factory F2T did not come with in 1988.
Some will say to make more power at the same boost, suddenly they are going to do better than factory engineers and programers with tons of experience and R&D backing them because they have a more modern engine controller and zero tuning experience. But it's fuel and spark, not magic. To make more power at the same PSI you need to advance spark or lean fuel (some engines make more power rich than lean, but the edge of lean usually makes more power) so more power means less of a safety window and relying more on the failsafes.
Unfortunately I have yet to read about a Megasquirt build on any car ever to date that didn't have a board, controller or part fail, is this because of wiring, shorts, user assembly...?
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