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Discussion Starter #1
I've been searching all morning but nothing. I'm planning on using 2.5" intercooler piping, so I was wondering which TB would would be better to use. Stock GE or LS400? I going to be using the XSPower ffim and shooting for only 400whp. This is my first attempt on installing a ffim so I'm guessing I need an adapter flang to allow the TB of choice to bolt on.

(1995 SC300 5 speed, Aristo ECU)
 

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I have built like 4 FFIM's so I'll share some knowledge with you.

The GE one is very long cause it has the idle valve integrated, no one really uses that you will be into the radiator practically (unless you shorten the FFIM as much as possible even then its a bit ugly).
It is the only one with an integrated IACV though, so when using any other one, you will need to get a flange for a TT idle valve which is a seperate unit.
TT valves are expensive so I run a sc400 valve (fits the same), and I had the flange welded underneath the intake.

here you can see it on the bottom back of the intake manifold to give you an idea
First FFIM I did not install it and regretted it cause idle was all over the place, now I have it on there its like stock.


now back to the throttle bodies you would consider running that dont have the idle valve integrated:

Never seen anyone use the ls400 one either although it is shorter the flange is not readily available. I put one of these on the stock intake manifold and I had to make my own flange etc.. its still quite bulky sideways its not the best choice either.

Now the XS power manifold comes with a flange for a 90mm mustang throttle body...

if you are on standanlone, you can just run the mustang 90mm throttle body but it costs $$$ cause a normal mustang throttle body is not 90mm, the 90mm are the upgraded special ones.

if you are on stock ecu you can use a q45 82.5mm throttle body which is a popular choice, I have one on mine. you have to get the flange changed to run this (wont bolt to the 90mm mustang flange the XS intake comes with) but RMR (ross machine racing) has the needed weld on flanges for these type of intakes for q45, mustang, etc.. only small issue is when using the 82.5mm q45 flange and throttle body, its a little harder to stick your arm down the opening to reach the bolts in the back (90mm my arm fits in nicely, 82.5mm not so much), so what I did was I took a dremel to the q45 flange and opened it up a little bit so arm would fit down easier...
also the q45 is a nissan throttle body so you have to rewire the TPS, or get the adapter to run a toyota tps (what I have).

with me so far?

now to give you another easier more expensive option... RMR makes a billet version of the q45 throttle body which is super sexy but costs $350. The reason I mention this is because they made these to bolt to a q45 flange... OR it can also bolt to a 90mm mustang flange. so if you get this throttle body, you wouldn't even have to change the flange. they also make the same billet throttle body in the 90mm mustang version, but 82.5mm is large enough for most and gives more flexibility in the future (some intakes are made for q45 flange). both of these RMR pieces will let you bolt a toyota tps onto it for the stock ecu and bolt to the flange that is already on the XS power intake, so it makes it an attractive option considering welding a new flange on will generally cost $100 at a aluminum machine shop.

So thats a basic rundown. and to give you an idea on sizes your 2.5" piping is 63.5mm
stock throttle body is around 65mm (2.55")
the ls400 is around 75mm (2.95")

so really the stock throttle body is larger than a 2.5" pipe, an LS400 would be fine for a 3" piping.
so you can see the q45 at 82.5mm (3.24") is more than enough as most people do not run larger than 3" intercooler piping once they upgrade.
The mustang TB at 90mm (3.54") is pretty massive and not really needed, although it does look cool.

I would also suggest getting some 1/4 NPT weld on bungs (aluminum type on ebay) instead of drilling and tapping for fittings.
The bungs are much sturdier and make for a better connection (learnt this on my second FFIM).
I got 3, the one on the bottom middle is for map sensor and FPR.
the two on the back... one is for brake booster, other is for a vac block that feeds all the little stuff (heater, bov, gauges, etc...)
and of course the big fitting is for the idle valve (you can order online)

 

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no dyno but you loose a bit of spool on the low end and gain some power on the top end with the FFIM, at least that is what it feels like to me, were not talking much here maybe max 10-15 ft/lbs difference. There is an old thread around here with a dyno on the stock intake with ACIS on and ACIS off, and the difference was about that much if I remember right. it was related to an aem ems v1 thread because in the basemap the aem people decided to leave it off, and they figured out just turning on the settings for it to make it work like factory got you that much more power on the low end which is nice, but no one is keeping the stock intake over a FFIM just for that bit of power. now people just go FFIM and quick spool valve with a big turbo and call it a day. all depends on what the car is built for.

I used to switch back to the stock intake every few years so I would feel the faster spool on the stock intake, but you have to remember to hook up the ACIS butterfly on the stock intake to a regular vacuum source so it works properly or else there is not much of a difference between the 2.

really the FFIM is more for aesthetics and ease of accessing plugs and injectors, and free flowing which is good for top end power, or when the stock intake becomes a bottleneck. take into consideration though that I have actually worked on a na-t that made over 700hp on e85 with the stock intake and throttle body, so really the stock intake isn't much of a bottleneck especially with 2.5" piping cause the throttle body is around the same size.

If you run 3" piping then the FFIM might show more results but basically its a bit of a tradeoff but the right sized turbo will make up for it.
for me I rather have the FFIM cause I disliked removing the stock one, although oil changes are a bit challenging with the FFIM in the way.

If you run 3" intercooler piping the FFIM will probably show a little more advantage as well compared to stock intake and might even make up for the loss of torque from not having ACIS.
 

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i used a ford explorer throttle, wich is actually very strange because they arnt that common here in aus, but i was at the a do it yourself wreckers and i spotted on in the yard and thought it would fit well. ill grab a pic at some stage. as for the iacv i used the factory GE one but instead of making a flange built into the intake manifold i made it remote with its own housing and just ran a hose to the intake. works great! , the only thing is i need a check valve to ensure it doesnt stay partially open during spool up!
 

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I did the remote IACV once but it never worked as good as stock, it did get the job done though but needed a check valve and piping, or you have to get the air source from the intercooler piping which is under boost so you don't need a check valve in that case. I ran mine off the intercooler piping as a inline check valve in that size was a huge ugly brass pipe thing that I could hear click open and closed lol so I decided against it. now I always weld the flange on the bottom and use the tt check valve rubber grommet thing, works like a charm everytime and I have to go to the welder anyways so really why not, avoids all that remote piping.

Yeah that is the thread, most everything is said in there. if you have the stock intake then use it, but if you want a FFIM then just go FFIM and after redlining it a few times you won't miss it that much.

There are tons of ways or reasons for it and against it but when you go ffim sometimes you want to just get it in there with the least amount of work but after running one with no iacv, the remote iacv, I eventually ended up making one with it. first few I tapped holes, but then I learnt to do the weld on bungs, cause it is more fool proof against stripping out threads in the future and helps with the spacing for fittings. throttle body I always used a q45, that hasn't changed but I will be getting the RMR q45 piece in the future.

When bolting the manifold to the runner, I also learnt that if you use a spare intake stud on the last hole, it makes aligning the gasket and getting it bolted down much easier, cause the last one is hardest to reach and with a stud you just have to get the nut on and spin it. since its after the last runner its not an airflow issue either. Thats just how I do it anyways, I have taken them on and off over a dozen times. Also tucking the harness under the runner is nice if you have the time, but not required.

OP you can us a ls400 flange but I looked all over the net when I wanted to try it on my project, and I could not find a proper weld on flange. I eventually cut one out of aluminum myself but it was thin and not as nice and shiny like the ones you can order from RMR for the q45 and 90m patterns.

here is a pic of the ls400 TB on the stock intake manifold and a link to the thread, I used the remote IACV with this setup and it worked ok.
http://www.clublexus.com/forums/performance-and-maintenance/576895-2jzge-ls400-throttle-body-mod.html
 

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Discussion Starter #8
Ali, thanks for the info. Very informative and helpful.
So far I have a IACV from a LS400 and I plan to purchase the flange from beechperformance. I'm still interested in using a a SC400 throttle body because there is one available in the yard right down the street. With that said all I would need to do is extend tps and iacv wires, bungs for vacuum, and a flange to bolt the SC400 up to the XSPower FFIM. Am I missing something? I know I'll need a new throttle cable and stuff.
 

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Ali, thanks for the info. Very informative and helpful.
So far I have a IACV from a LS400 and I plan to purchase the flange from beechperformance. I'm still interested in using a a SC400 throttle body because there is one available in the yard right down the street. With that said all I would need to do is extend tps and iacv wires, bungs for vacuum, and a flange to bolt the SC400 up to the XSPower FFIM. Am I missing something? I know I'll need a new throttle cable and stuff.
they dont have a flange for the sc400 throttle body (same as ls400 one), so you have to make your own like I did. they only have ones for q45 and the mustang 90mm and a few other random ones. you do not need to extend the tps or IACV in my experience, they are long enough already for where I put them, just unwrap the harness around it a little bit and you can reach quite far with those wires. rest sounds good. only extending is the injector wires sometimes if you tuck harness under lower runners.



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Thats a FFIM for sure, looks like a ford throttle body as you mentioned.
 

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yea i had to make a flange that bolts to the ford flange and then bolts to the outer part of the manifold. the plenum is acctually bolted onto the runners with hex head bolts, so to tighten them i had to fit my arm inside the whole plenum, meaning it had to be a minimum of 90mm from the flat part to the opposite side of the tube.
 

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The only way you can use an OEM throttle body is if your intake is on a serious angle. Foster used one (UK forum), not sure his user on here.

I fitted my FFIM and I must say, with no angle you need to ensure your throttle body doesn't sit too close to the power steering output. I had a right ball ache and if you have any issues, it's a pain. Definitely ensure fitment when welding flanges.

As Ali said, place the IACV flange underside. Mines well too close to the strut, the welder didn't listen and luckily it still fits.

Here's a shot of my mate's FFIM using OEM GE throttle body.



 

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Suggestions on vacuum distribution blocks? I need one for my setup. And what all is it feeding for you Ali?
 
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