All credit to Joe AKA Squiffswift (Ukswift) / mojoe (teamswift username) for this Post, i'm just hosting the pics.
I've also turned the original document into a PDF for ease of printing which can be downloaded at the bottom of this post.
SR20 Throttle Body Conversion
To carry out this Conversion you will need the following: Rough Estimate Prices on what I paid for (price can + or – depending where you source your parts from)
• SR20tb (est£40)
• Up rated fuel rail (est£30)
• Intake manifold (est. £40)
• Air Flow Meter (est. £15)
• Adjustable Fuel Pressure Regulator (est. £100)
• Intake hose (est. £30)
• Hose joiners and reducers (est. £30)
TOTAL £285
This sounds expensive, but I personally bought these parts over a few months, and even had some lying about, the price can seriously be reduced if you have spare Intake Manifolds, AFM’s, AFPR etc or buy things from scrappy’s, eBay or other swift owners!
THIS IS JUST A ROUGH GUIDE
Labour would also have to be a factor if you are unable to carry out the following jobs by yourself.
THE GUIDE:
• SR20tb (can source these from Nissan 200sx (1.8 and 2ltr), 2ltr primira’s, 2ltr sunny’s etc, sizes can vary from 50,55 and 60mm (depending upon year and size of engine) Keep an eye on scrap yards, eBay, Nissan for sale forums (should be looking to pay no more than £40 for a decent one) You will need to source the old cable arm and spring from your swift, it is a bit tricky to do, but patience is the key . Also you will need to bolt the TPS on the other way around, due to the shape of the SR20, it still works fine this way.
• Uprated fuel rail, one way to this is to get a mk1 fuel rail, unbolt the stock fuel regulator, and tap a BSP thread (its tapered and is self sealing), if you go into any gas/camping shop they should be able to supply a brass fitting, this will allow you to clamp a fuel hose to and plum in an ‘Adjustable Fuel Pressure Regulator’ Another way is to buy an aftermarket fuel rail (teamswift, turbine tech I think can supply this) Or if your handy with a welder cut the stock regulator off the mk2 rail (on the left hand side if your looking at the engine) weld a plate with a lug on.
Choice out of the three will depend on, time, money and skills. The easiest would be to buy one ready made from turbine tech or any other swifty performance places. I personally adapted the mk1 fuel rail. It is always handy to have a spare intake manifold and AFM housing as modifications could go wrong or take longer than expected • Once you got a tb, bolt it in place, open the butterfly valve and scribe around the inside (so that you know how much to grind away) Take tb off and by using a flapper drill bit (loads of segmented
sand paper) work you way in circular motions around the inside of the intake manifold, due to the manifold being made out of aluminium it is very easy, so should only take you about 5mins!
• The Air Flow Meter housing as standard is 45mm, this will need to be opened up to 49mm, but to be safe go to 48.5mm. Any good machinist should be able to do this for you in a few mins. (By using a lathe) The AFM from theSR20 is 49mm, but the ‘HITACHI’ sensors look the same but are slightly configured different, so to keep the original swift one and just bore out.
• Get your self an Adjustable Fuel Pressure Regulator, FSE are the main manufactures and it doesn’t really matter what one you use, but it should be able to adjust from 20-60psi (rough guide) Again check eBay as there is always bits and bobs on there! The standard fuel pressure is 35-36psi, but to run the SR20 you should have
40psi at warm idle! The AFPR needs to go on the return fuel line, you can identify this by tracing back to where the original one went (left hand side) pick a place where you can securely bolt it, I fixed mine onto the bulk head (at a later date I will make up a fixing bracket that goes onto the intake manifold, but its up to you!)
• Larger intake pipe, I used a 90’s civic induction pipe. It will need to be cut down as you will only need about 8 or so inches where there is about 45° angle and a breather lug (this will be used to put the idle hose) You an pick these up very cheaply on…wait for it…eBay! £20 or so, I got mine from the eBay.com as they love their civics and it didn’t cost much at all to get shipped. Then again you could use a right angled reducer elbow from samco hoses or get a custom one made up…depending on the modifier. You will need to get some reducer hoses to attach the tb-induction pipe, and the induction pipe-AFM housing. I used samco hoses as they were easy to order and to see what sizes, shapes were available….this came at a price, I think I paid about £30 or so for the two! As you can see it is a very tight fit, I had to cut about with the induction pipe and some bits of the samco’s to get it to fit.
That should be about it really, you can only adjust idle from the small screw…but every time you do you should reset the tps (but don’t worry about that until you got it idling ok) you should check the fuel pressure and adjust to 40psi AT WARM IDLE. You will notice a big difference in sound (very throaty) and sometimes the throttle feels like it’s either off or on. The car felt like it had a bigger engine as I felt low down torque improved. (As I didn’t have to change down to low gears as much)
ONE THING TO REMEMBER! The only real way your going to get maximum benefit from this mod is by getting it tuned and setup on a rolling road, Also by having a piggyback ECU/tuneable chip (unichip etc) they can set it up and make it work very well. Regardless to what you do to your car, you should get it tuned/setup on the rollers or actual on the road tuning, this will ensure your car will run at its maximum potential and that your not loosing performance rather than gaining.
Conclusion
Is the SR20tb worth it?
If you can’t do a lot of the work yourself and need to pay for labour, then you’d spend a lot more than what you’d get out of it. Once the car was going, it went and sounded awesome. I had a lot of other things done at once so this also would be a result of that. Since I have removed the tb, just down to the that I couldn’t adjust the idling to my liking, I think a lot of this was down to incorrect tps adjustment, because I do a lot of city driving I’d rather have something reliable!
How much BHP would I normally expect?
4-6 bhp, doesn’t sound a lot, but that’s still 4-6% bhp increase from standard. Depending on your current/future mods will also affect this, REMEMEBER every little helps! I hope this will help people with the conversion and give guidance to what needs to be done, if I have missed or messed up anything please let me know so that I can make amendments.
Cheers Joe Lewis
How To: SR20 Guide PDF
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must be some type of Suzuki curse to forbid any Australians owning any type of Suzuki lips, diffusers or flares 
/end ousting 
