# DIY- Individual Throttle body design complete



## CdnDub (Dec 3, 2002)

overall design is done.. got all the tubes tack welded in place.. and its frickin awesome.. 16" from the valves to the throttle plate or 19" from the valve to the top of the TB.. tapered from 48mm at the lip of the TB down to 36mm at the valve should have great velocity
















































A note to the wise.. if you plan on running EFI on a solid lifter head use an 84 GTI head.. its got the holes for the digifant fuel rail and injector harness in it and tapped with 4mm threads already.. the 83 GTI head which i'm using has no such things.. the 84 head also takes digi injector inserts perfectly the 83 head.. no such luck.. live and learn i guess
i started another thread in the mk1 forum a few days ago and keep updating it but thought you guys who arent mk1 drivers might want to know how to do this..
http://forums.vwvortex.com/zerothread?&id=942528

_Modified by CdnDub at 6:57 AM 7-22-2003_


_Modified by CdnDub at 6:58 AM 7-22-2003_


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## URIN 2ND (Oct 29, 2001)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

Excellent work! http://****************.com/smile/emthup.gif


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## Coupe_88 (Feb 7, 2003)

*Re: DIY- Individual Throttle body design complete (URIN 2ND)*

I second that !


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## 84_GLI_coupe (Apr 3, 2001)

*Re: DIY- Individual Throttle body design complete (Coupe_88)*

Awesome setup! It's gonna be a screamer! So when are you gonna bring it to the Island meets?


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## Sn0wMaN (May 26, 2003)

Those runners arent gonna be to long are they? Cause the stock mani hugs the fuel rail and head alittle more! Looks good though!


_Modified by Sn0wMaN at 7:17 AM 7-22-2003_


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## B3VR6 (Jan 4, 2000)

Looks good. How are you going to clean up those welds on the inside of the piping?
It looks like once you have filters on the throttle body inlets, you'll have some serious interference with the hood. Are you planning on making a cut out in the hood for clearance?


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## CdnDub (Dec 3, 2002)

*Re: (B3VR6)*

hood will clear perfectly







i'm going to use 3" high K&N cones.. 
i dont know if i'll make it over to any of the island meets but the car will be at the great canadian show if it kills me. <august 17th>
the runners shouldnt be too long they should be perfect for the power band i'm after.. if they are too long all i gotta do is go back in and cut and weld some more pipe.. the welds inside the pipe are actually pretty smooth.. its the outside that looks ugly.. and honestly i dont care how that looks cause its structural.
The welds i'll clean up inside using a die grinder and an extension.. i've got a high speed cutting bit as well as some sanding discs etc.. its not going to be perfect down near the port entrance since i had to dent and mangle the tubes to clear the bolts <thats the downside to going with huge ports on the head..>.


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## A1Rocco (Oct 6, 2001)

*Re: (CdnDub)*

WOW, All I can say is WOW! I'mma gonna come out there and drool on that thing even if I have to walk all the way.
I too am surprised that you will have enough hood clearance for 3" filters, nice.
The intake reminds me of the Audi 5000 non-Turbo intake, ever consider using one of those to start with and cutting it up?


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## CdnDub (Dec 3, 2002)

*Re: (A1Rocco)*

I thought about starting with something like that.. but i cant weld aluminum properly and cutting it is a pain compared to cutting steel.. eventually i'd like to build a manifold out of machined aluminum but for now this will work just fine to see if the idea actually works







i'm still alittle worried that my runners are Too long.. all the ITB setups i see keep them really short..


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## CdnDub (Dec 3, 2002)

*Re: (CdnDub)*

I should mention i "think" i have enough clearance for 3" cones.. they will however tuck right up against the hood vents







if i dont i'll work something else out using an airbox and a single large cone.
I'll have to test fit the manifold back on the engine in the car now that its all made and see exactly how much room i've got.
if its not enough i can always cut a hole in the hood and cowl it.
it might scare the passengers to see 4 little air filters poking thru the hood with the cowl facing the windsheild tho.


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## VeeDubClub82 (Jan 23, 2002)

*Re: (CdnDub)*

how are you running the MAF system into it. Was it eliminated. If so how??


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## CdnDub (Dec 3, 2002)

*Re: (VeeDubClub82)*

MAF? you mean CIS?
I'm going with a MAP based system..called MegaSquirt.. seems quite a few people on here are using it..
It needs Coolant temp sensor input, intake air temp, MAP, TPS and oxy..as well as an RPM input from the dizzy.


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## jueve grande (Oct 21, 2001)

*Re: (CdnDub)*


_Quote, originally posted by *CdnDub* »_It needs Coolant temp sensor input, intake air temp, MAP, TPS and oxy..as well as an RPM input from the dizzy.

But as with any speed density based fuel injection, it requires a good bit of tuning to get it right, and it is still not very flexible. Megasquirt is pretty cool though, especially if you are on a pretty tight budget.


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## 2L Bunny (Aug 15, 2000)

*Re: (jueve grande)*

Little bit of advise. Be very carefull with cam selection if you want to use a MAP fueled system with those big ITB's. Not sure if you were at WaterJam up there in BC in 2001, but I had my ITB Rabbit there you might have seen. With a Kent "285" hydro cam, it didn't make enough vacuum to run correctly with 45mm ITB's.
hth,


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## CdnDub (Dec 3, 2002)

*Re: (2L Bunny)*

Hey TIM!! we've talked via email etc..
I checked out your car. thats what made me fall in love with ITB's..
i've got a TT 288deg cam with 12:1 compression should make a little bit of vacumn.. dynamic compression is somewhere around 9.8:1 with that cam and my cylinder pressures should be about 185PSI <according to all the math>..
ps the TB's are only 42.5mm throttle plates so they should be smaller than your 45's.. they just taper from 48mm down to 42mm at the bottom.
If Map doesnt work you can run Megasquirt in AlphaN mode without the MAP input.. or they are testing new hybrid code like the Ferrari F40 uses.. alpha N below 3000rpm and then SD above.. should be fun to play around.. Timing is actually my main concern right now.


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## CdnDub (Dec 3, 2002)

*Re: (CdnDub)*

You guys were right once its all bolted down its not going to clear the hood.. and its also slightly off from the hood vents <cant move it any further back towards the firewall tho with the injectors on the back etc>.. so i'll be cutting a nice hood vent then do a cowl induction setup with a low profile metal cowl facing the passenger <ie windsheild>.. K&N cone filters <pn RC-2330> will stick up about 1" above the hood line.
Honestly i think it'll look pretty damn cool.. but it does ruin my nice sleeper look.


_Modified by CdnDub at 2:39 PM 7-23-2003_


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## p_ferlow (Apr 11, 2003)

*Re: (CdnDub)*


_Quote, originally posted by *CdnDub* »_i dont know if i'll make it over to any of the island meets but the car will be at the great canadian show if it kills me. <august 17th>

I'll see you there dude! Looking forward to checking out your ride. First time at that show, haven't been to a vdub show in years. Used to go back in late 80's when I drag raced air-cooled bugs.


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## CdnDub (Dec 3, 2002)

*Re: (p_ferlow)*

hehe.. you'll get to see sharkey <a 50's beetle> if you show up he's got my old 2161 flat four in there but has gone a little extreme with a CB peformance EFI/Turbo system.. last i heard he was pushing 380hp from that little motor








I used to have aircooled stuff before i got into waterpumpers..


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## Cabby-Blitz (Sep 2, 2002)

*Re: (CdnDub)*

Looks really cool and should sound like a beast. After all this work Im assuming you are going to clean up the runners and make them pretty


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## A1Rocco (Oct 6, 2001)

*Re: (Fst'N'Frs)*

I'm wondering about that runner length too Dave, it may be a bit too long for maximum top end perf with that 288. I would expect to see something a bit shorter on an engine that was designed to pull from 4500 to 7500. But like you said, if they need to be changed you can cut some out. Having a velocity stack on the entrance is also helpful for tuning, did you consider that?


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## CdnDub (Dec 3, 2002)

*Re: (A1Rocco)*

I had considered velocity stacks but i dont think that would work very easily since there is no easy way to mount them to these TB's.. for now i'll stick with the lenght and see how much power/torque it makes and then i can go back and change things later if i'm not satisfied.


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## A1Rocco (Oct 6, 2001)

*Re: (CdnDub)*

I think that makes sense, I mean wouldn't you rather have a bit too much then not enough and then have to add in. I think removing some would be a bit easier, then again there is that taper to work with.
PS. 42.5 is BIG. We were seeing 38 to 40mm ITB's on the 1.8 L 16v Miata's that were tuned to run on the street as well as track. They were making 160 to 170hp from under 11:1 comp. and with programmable FI. The runner length from the bodies to the head was anywhere from say 6" to 2" but they were also using velocity stacks to tune the total length and aid air entry. I think if you ultimately have to shorten yours you will have a better opportunity to use stacks to tune the total length. And with your obvious ingenuity you will be able to devise a way of attaching them. But I can't wait to hear that beast running!


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## CdnDub (Dec 3, 2002)

*Re: (A1Rocco)*

I'm going to have a chat today with a pro here at work.. he road races a silver CRX which just dyno'd 248hp at the wheels from a 1.8L with 13:1 compression.. its running ITB's and insane cams <Vtec does work nicely>.. his torque was only around 150ft/lbs tho..
I looked at shortening the runners and i still could.. i'd really prefer not to cut a hole in the hood.. <like that sleeper look>.. but if i shorten the intake there isnt much room to mount the TB's and filters <since they point at the firewall>.. its a bit of a catch 22.. we'll see what i can devise.
a few people who know induction have suggested shorter runners now so i may go that route and try to keep the total length at 10" or less <tb opening to the valve>.. 19" is a little long.


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## Kameirocco (Dec 20, 2002)

*Re: (CdnDub)*

put it in your car already!!







lol j/k deff nice work man!! how much was it all together??
NOah~(KAmeirocco)


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## CdnDub (Dec 3, 2002)

*Re: (Kameirocco)*

its mounted in the car







did that last night.. just to see how it all lined up.. going to take some measurements tonight and see if i can shorten up the manifold at all.. i dont think i can take much out or change the angles without hitting the firewall.. so we'll try it long.


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## Ricestalker (Sep 8, 2002)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

That looks pretty neat. I saw on neons.org a similar DIY post using GSXR throttle bodies. ( http://www.neons.org/forums/viewtopic.php?t=48253 ) What ones are you using? Here is a pic of the Neon ITB intake for those interested. They can get by with short forward facing runners since the intake ports of the head face forward.








Chet


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (Ricestalker)*

those are the earlier throttle bodies. same idea tho.. i just removed the second set of throttle plates.. it was super easy.
Anyways. after thinking long and hard i went back and shortened the intake by 4-5".. which gives me 4-5" of hood clearance looks like i'll fit those air filters under there afterall.. woohoo!
heres some new pix.
























































That should help the top end and still give me some decent torque.
it puts my intake runners between 13 and 15" <depending on where you measure>








time for a











_Modified by CdnDub at 6:14 AM 7-24-2003_


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## Ricestalker (Sep 8, 2002)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

I like that better. I'd love to see a dyno graph once you get that thing sorted out. Not to go off topic but who did your cage and do you have any more pics of it? I like the fact they tied into your front strut towers. Very sweet.
Chet


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (Ricestalker)*

I did my cage







and thank you.. its a S&W racecars 10point <comes in boxes as a bunch of pipe that needs trimming and notching for $250 US> that i added another 6points to <including the bars into the front struts>..
heres an old thread i had with the roll cage pix before the car was painted
http://forums.vwvortex.com/zerothread?id=796719
and heres some pix of it after it was all done
































lol ok i'll stop
if you really want to see it just go check out the full project gallery i've got at
whole car start to finish.. i built it all myself.. bodywork, paint, engine, efi system, etc.. only part i had help was the transmission.
_Modified by CdnDub at 6:36 AM 7-24-2003_


_Modified by CdnDub at 6:46 AM 7-24-2003_


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## p_ferlow (Apr 11, 2003)

*Re: DIY- Individual Throttle body design complete (Ricestalker)*

Nice cleeeeeeeeeeean engine bay dude!


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## dohc (Sep 28, 2001)

*Re: DIY- Individual Throttle body design complete (p_ferlow)*

I did a quick calc in my head for your ideal runner length from valve to plate. I've come up with ~11"-12" for a peak torque at ~6500rpms. You always want your peak torque rpm's to be at about 1500rpms below your redline.
Did you ever consider just running the TPS as the load input? I know my TEC III will switch from tps to map at higher rpms, but I'm not sure a megaspirt will. What is this alpha N and SD you speak of? You going to run closed lope at part throttle?
The motorcycle carbs I'm running (soon) have removable velocity stacks, I'm pretty sure yours has them too, maybe they were just removed when you bought them. Go to a bike shop and ask them to look it up, they will make a noticable difference. You'll have to get rid of your cone filters though (maybe). I was planning on putting on just go-cart style foam sock filters on top of the stacks, foam works better and flows more are then paper, but it needs more maintenance and is not as durable...but I can live with that.


_Modified by dohc at 6:48 PM 7-24-2003_


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (dohc)*

i'm not sure i'm after an 8000rpm redline.. i'll be happy if my redline is around 7600rpm or so.. which means i'm looking for torque peak around 6100 or 6200rpm's
with my current setup my valve to the throttle plate is 13" i may be able to shorten it a little more but not much without spacing the TB's differently.
AlphaN is TPS based input for calculating fuel.. thats what i meant about hybrid code.. i think a few MS'ers are testing it out.. it uses TPS etc at low rpm's and switches over to MAP for higher rpm fueling once there is some vacuum.
tuning will be fun. I think i'll just try this as is and see where my power drops off if i think the manifold is a restriction after dynoing it i'll go in and change things again.


_Modified by CdnDub at 11:49 PM 7-24-2003_


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## dohc (Sep 28, 2001)

*Re: DIY- Individual Throttle body design complete (CdnDub)*


_Quote, originally posted by *CdnDub* »_ i'm not sure i'm after an 8000rpm redline.. i'll be happy if my redline is around 7600rpm or so.. which means i'm looking for torque peak around 6100 or 6200rpm's
with my current setup my valve to the throttle plate is 13" i may be able to shorten it a little more but not much without spacing the TB's differently.
AlphaN is TPS based input for calculating fuel.. thats what i meant about hybrid code.. i think a few MS'ers are testing it out.. it uses TPS etc at low rpm's and switches over to MAP for higher rpm fueling once there is some vacuum.
tuning will be fun. I think i'll just try this as is and see where my power drops off if i think the manifold is a restriction after dynoing it i'll go in and change things again.

_Modified by CdnDub at 11:49 PM 7-24-2003_

You are the quickest replyer EVER















So your in the zone then, 13" is almost perfect. Had I had know that mega-spuirt was playing with the TPS to MAP switch software I never would have fork out the big $$$ for a TEC III








Oh well it has some other nice features.
Where are you going to hook up your MAP sensor, just to one runner? Ever thought about linking the all the runners with really small tube dia. pipe (since you only need a signal) and running your MAP into that. It would also benefit your power brake boaster as well. The small dia tube should not effect the individuality of the ITB's, as the flow is very small.
So closed loop at part throttle?
Did you catch the edit of my last post?


_Modified by dohc at 7:09 PM 7-24-2003_


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (dohc)*

I noticed you added a bit at the bottom..
I'm actually trying to buy an ITG foam airbox from a place in the states it comes with the baseplate already cut for the Suzuki ITB's and you are correct i am missing the little rubber velocity stacks.. I asked the guy selling the ITG stuff how the baseplate mounts since there arent any bolts etc.. he said oh you just remove the rubber velocity stacks from the stock airbox and glue the baseplate to them using some silicone then they mount right up like stock








i've been calling around the local bike wreckers to see if anyone has something i may try to drop by one tomorrow and show him the TB's and ask if he's got them.
oh and for the Map sensor the stock suzuki one hooked into all 4 of the TB's using a little vacumn tree with small diameter silicone tubing.. in fact each TB has two manifold vacuum nipples on it. We'll see how the megasquirt code actually works.. Eric Falhgren who's been designing some of the MS code stuff and is a VW audi guy seems to think i should have enough vacuum with my 12:1 CR and that cam to actually run map with a reasonable idle.
Lol and as for the quick response i just happened to be checking my email when the vortex notifier thingy came in.


_Modified by CdnDub at 12:07 AM 7-25-2003_


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## dohc (Sep 28, 2001)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

Suzuki thinks of everything don't they? Of all the 3 Japanese brands of motor vehicles I've owned (cars and bikes), only Suzuki has never given me trouble http://****************.com/smile/emthup.gif
You'd said you will run an oxygen sensor, for closed loop right? Or just air/fuel monitoring?


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (dohc)*

definitely running an oxy for closed loop.. eventually it will be a wideband <already have the wideband sensor> when Ultra MegaSquirt comes out.. that will make tuning for best power much easier.. for now i've got a single wire just to help out with emissions.. i figure exhaust will be hot enough with 12:1 compression to warm up the sensor for closed loop.


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## 2L Bunny (Aug 15, 2000)

*Re: (CdnDub)*


_Quote, originally posted by *CdnDub* »_Hey TIM!! we've talked via email etc..
I checked out your car. thats what made me fall in love with ITB's..


I'm glad I had that effect, as my ITB's are now down the road. I need to check up on 'em tho, see if they ever went on a car. Going back to carbs on that beast, and using my SDS on the daily driver.
Good luck, let us know when you get it running....


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## CdnDub (Dec 3, 2002)

*Re: (2L Bunny)*

Could you just not get it tuned right with SDS? is that why you went back to carbs? did you end up going for a bigger cam with the carbs or sticking with something more "streetable".. i forgot to ask what compression ratio you were running on your 2L bunny..
btw. Huge Thanks to my Good Friend Nick who just ordered me a present from PeterDmotorsports in Phoenix..
ITG air filter is on its way..








precut baseplate to fit the suzuki ITB's as well.


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## dohc (Sep 28, 2001)

*Re: (CdnDub)*


_Quote, originally posted by *CdnDub* »_Could you just not get it tuned right with SDS? is that why you went back to carbs? did you end up going for a bigger cam with the carbs or sticking with something more "streetable".. i forgot to ask what compression ratio you were running on your 2L bunny..
btw. Huge Thanks to my Good Friend Nick who just ordered me a present from PeterDmotorsports in Phoenix..
ITG air filter is on its way..








precut baseplate to fit the suzuki ITB's as well.


What's the website for PeterDMotorsports? I wanna see if they have filters for the carbs I have.


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## CdnDub (Dec 3, 2002)

*Re: (dohc)*

http://www.peterdmotorsports.com


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## 2L Bunny (Aug 15, 2000)

*Re: (CdnDub)*


_Quote, originally posted by *CdnDub* »_Could you just not get it tuned right with SDS? is that why you went back to carbs? did you end up going for a bigger cam with the carbs or sticking with something more "streetable".. i forgot to ask what compression ratio you were running on your 2L bunny..


Oh no, I got it tuned great. The problem was in the ITB's themselves, they kept shearing off fuel rail bolts, and engineering another mouting system was going to be a big job. So they're gone now. I was running a Kent 285 hydro, and that thing idles like a stock digi motor, it was great. Now on to dual 40's and a Delta 285 at .050" solid cam, should make HP to around 8ish....


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

hehe look what i got in the mail today to top it all off.. just waiting for the suzuki velocity stacks now <should be here tomorrow> and i can mount it all properly..
looks like i'll have to go back and shorten the manifold again tho.. it doesnt clear the hood with the filter <about 1" too close>
Btw.. huge Thanks to my Buddy Nick in the UK who bought me the ITG filter as a gift, it gets me one step closer to having this monster on the road.
And a big thumbs down to myself who cooked two hall sensors last night trying to figure out how ignition systems work.
also a few pix of how my new wiring harness turned out.. whatcha guys think? 
:agree: :grinno: <its still in progress i've got the EFI and ignition harness to add>


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## MikeBlaze (Aug 9, 2001)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

Any updates?


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (MikeBlaze)*

A breif update would be that after the 5th revision the intake manifold is finally done.
I had to go back and cut out another 1.5-2" in order to make the new Megaflow and velocity stacks clear the hood as well as the airbox i made to cover the blower motor.
I painted the manifold last night after i finished porting it and sealing it etc 
I'll post some pix tonight after its all bolted in and in its final resting place. Turned out really nice in the end and i'm pretty happy with the lenghts and design.
One curious thing to note is that the velocity stacks that come from suzuki with these TB's are different lengths.. the inner two are about 3/4" longer than the outer two.. it may be to compensate for different runner lenghts or even the way the ports go in the head on the suzuki GSXR engines.. but for now i've got two long and two short stacks. Later i might try to buy another airbox so i have two sets of 4 long and 4 short stacks to play with for tuning.
With any luck the car will be running before the weekend.. I've got everything else finished so its just final wiring, installing the dash and programming megasquirt.


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

As Promised she's all done.
















































Thanks again to my Buddy nick in the UK for buying me the wicked ITG filter and premachined baseplate it totally tops it off.


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## dohc (Sep 28, 2001)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

What's that welding box and PVC for? Did you re-route the fresh air intake for inside car so you don't pull in stinky underhood air? If so, good idea http://****************.com/smile/emthup.gif 
Also have another question for ya. You said you plan to rev to about 7500rpm, what kinda oil pump are you using for that, stock 8V?
Will it supply enough oil?


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## CdnDub (Dec 3, 2002)

*Re: DIY- Individual Throttle body design complete (dohc)*

Yup thats a fresh air intake reroute.. i ducted it into the passenger side fender with a cone filter and fender liners.. should get nice clean air from there.. but we'll see how well it works.
And i've got a brand new hydraulic lifter oil pump in there so hopefully i have enough oil.


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## Sead (Sep 3, 2002)

*Re: DIY- Individual Throttle body design complete (CdnDub)*

Is the hydraulic oil pump a higher rate?


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## theuean (May 11, 2000)

Yes.
Congrat's Dave. Now quit messing around designing stuff and turn the key Haha... actually I'm glad to see you taking your time. Everyone I've known (this majorly includes me) was so excited to get the new motor running that necessities turned into "I'll do it once it's running!"s and then once it did, some were ignored, resulting in a half-assed car with a sweet motor that needed tweaking.
Good job man. Great Canadian is going to be the best year ever


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## CdnDub (Dec 3, 2002)

*Re: (Speedemon)*

Thanks Sean







.. it is taking longer than i wanted it to.. i was hoping to be ripping up the streets of vancouver by now but thats ok.. I decided i wanted progammable Spark as well as fuel and it slowed me down a little.
I just got the new and very beta MegaSquirt&Spark code loaded onto my Megasquirt ECU.. it replaces the IDLE bypass valve circuit with ignition output to fire a coil. now i just gotta figure out how to setup my dizzy so its triggering an ignition event 50deg BTDC so that the MS box can back it off and control it.
and Sead.. yes the Hydro oil pump pushes more volume than the regular solid lifter pump.. not sure if its higher pressure but the volume is higher. its just got larger gears.


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## dohc (Sep 28, 2001)

*Re: (CdnDub)*

In regards to the oil pump, what you might wanna do is enlarge the return from the head so that eccess oil doesn't accumulate there...little late to have mentioned this now that your engine is together...


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