# Individual Throttle Bodies



## FiredragonCT (Sep 1, 2004)

Hi all

I know you are not very familiar with the GA14 motor - I have one of these in my car - it started out as a 88Hp engine and after some mods (Intake system, headers, freeflow exhaust, 272 degree cams, Unichip and rev limiter override) I have managed to work it up to 116Hp.

Now I will be lifitng the compression ratio on the engine from 9.5:1 to 10.1:1 and I also want to use Individual Throttle bodies. Does anyone know where I can get Individual Throttle Bodies for the GA16? This should be useable for the GA14 as it is the same bottom end and basically the same head - just the stroke and piston size that vary.

All I need to do is manufacture some 40mm trumpets for the ITB's and they should work 100%

I would really appreciate it if someone can help me in this regard.

Here is a pic or 2 of the car and engine... (I have not seen this shape of Nissan Sentra anywhere other than in South Africa)









Still before the headers were done - the thin green line leading to the intake manifold is water/methanol injection to curb detonation when advancing the timing)









The bonnet scoop was done by myself to get more cold air to the Intake and aftermarket air filter - works like a charm!









Close-up of the scoop....









The rear of the car...


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## chimmike (Oct 17, 2002)

as far as I've found, there are no individual throttle bodies available for the GA, any form.

however I think there are other modifications you can do that will benefit your car better than ITBs. A good way to do so is simply tuning it well with the modifications you have. Use the unichip and get on a dynamometer with a wideband O2 sensor and have a professional tune the air/fuel ratios properly.

Also, simple intake manifold massaging or cylinder head porting and polishing to complement the raised compression and other mods can help you out.......but I wouldn't expect a whole lot more out of that engine, it's simply not a big naturally aspirated performer.


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## asleepz (Feb 24, 2004)

Sorry to ask but what's that thing on the back bumper?


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## BII (May 13, 2004)

♣AsleepZ♣ said:


> Sorry to ask but what's that thing on the back bumper?


It looks like a hitch ball.

But Chim's right, do a head port/polish, raise the compression more than 10:1, maybe get a crankshaft and pistons/rods from a GA16 to raise displacement.
You have to really be breathing heavy to justify ITBs. The upside to ITBs is that A/F ratio is more even and some cylinders aren't running richer than others due to poor manifold design. The downside is that unless the cylinders are pulling hard enough to suck that much air, you'll experience lag of the line. 


As far as ITB's, you'll have to get it custom fabricated. I've seen 4AG guys (notorious cheapskates) use motorcycle TBs. The electronics/wiring might be a daunting task as well.


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## morepower2 (Apr 19, 2002)

bII said:


> It looks like a hitch ball.
> 
> But Chim's right, do a head port/polish, raise the compression more than 10:1, maybe get a crankshaft and pistons/rods from a GA16 to raise displacement.
> You have to really be breathing heavy to justify ITBs. The upside to ITBs is that A/F ratio is more even and some cylinders aren't running richer than others due to poor manifold design. The downside is that unless the cylinders are pulling hard enough to suck that much air, you'll experience lag of the line.
> ...


TWM makes ITB's for the ga that might fit. I'd do 11:1 and I don't know why you need water injection on an NA car if its programed halfway right.

Motorcycle TB's can stick wide open on large displacemnt car motors


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## BII (May 13, 2004)

With TWM manifolds you'd still need to fabricate an adapter plate to mount the TBs, no?

And I'm not endorsing using using Motorcycle TBs, should have been clearer with the sarcasm, not everyone hangs around AE86 guys, sorry.

I do know of a 510 running 13:1 compression and ITBs, he definetly needs ITBs.

And 9.5:1 NA and water injection? I don't think I can push my timing that far ahead and merit water/methanol. But if you decide to go to 13:1 or something, it could come handy, maybe?


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## fstb13ser (Nov 9, 2004)

FiredragonCT said:


> Hi all
> 
> I know you are not very familiar with the GA14 motor - I have one of these in my car - it started out as a 88Hp engine and after some mods (Intake system, headers, freeflow exhaust, 272 degree cams, Unichip and rev limiter override) I have managed to work it up to 116Hp.
> 
> dam bro your car looks bad ass even dough i'm not a big fan of the decals nice ga :thumbup:


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## morepower2 (Apr 19, 2002)

bII said:


> With TWM manifolds you'd still need to fabricate an adapter plate to mount the TBs, no?
> 
> And I'm not endorsing using using Motorcycle TBs, should have been clearer with the sarcasm, not everyone hangs around AE86 guys, sorry.
> 
> ...


I think the S&B ITB's bolt right to the TWM manifold.


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## FiredragonCT (Sep 1, 2004)

Hey guys, thanks for all the advice and compliments.

The reason for the water injection is purely to give the motor a quick cool down right before the 1/4 mile, because even if I could advance the timing enough the knock sensor would just hamper it...

The reason I am only lifting the compression ratio to 10.1 is that these GA14 motors starts "pinging" (detonating) as soon as you go any higher - at least Ive already got the Water injection for when that happens.

And this is even running on 97 Octane (all that I use on the car as this is regular pump fuel here) I might be able to push it to 11:1 but then I will only be able to run on our racing fuel (102.3 Octane)

As far as the ITB's go - I really want to stay away from the bike ITB's - I would rather go for the Toyota RXI (1600) ITB's - just minar conversions to make them work (like shortening the trumpets) and the intake manifold to bolt them on I can have manufactured locally. But to be hinest I dont really like bolting Toyota parts to my Nissan  

Oh - yeah - its a hitch rail at the back of the car - as I race in the streetcar series our cars has to bee 100% roadgoing and legal - the hitch-rail actually extends behind the back of the bumper - just in case someone nudges me from behind on the racetrack... They will be in for a nasy surprise :thumbup:


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## StevenLK (Jul 15, 2002)

hmmm, just woundering. shouldnt u find an intake arm that has a bend like the (96 civic lx's on ebay).... with that sharp of turn u'll have major turboulance i'd say?


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## FiredragonCT (Sep 1, 2004)

StevenLK said:


> hmmm, just woundering. shouldnt u find an intake arm that has a bend like the (96 civic lx's on ebay).... with that sharp of turn u'll have major turboulance i'd say?


I have had various arms manufactured (at the local exhaust centre) and for some or other reason this arm works the best to date - maybe just the right sort of turbulance??


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## himbo (Sep 20, 2003)

there are some articles on the internet on using motorcycle ITB (esp GSX 1000's) on civics, they actually come out looking pretty clean and they run fast as shit!!! i dunno, just an idea

btw, motorcycle itb's are pretty plentiful and cheap


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## FiredragonCT (Sep 1, 2004)

himbo said:


> there are some articles on the internet on using motorcycle ITB (esp GSX 1000's) on civics, they actually come out looking pretty clean and they run fast as shit!!! i dunno, just an idea
> 
> btw, motorcycle itb's are pretty plentiful and cheap



Thanks - I will play around a little bit and see what I can come up with....
:thumbup: 

Will post when I have some results


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## 510Mods (Feb 21, 2005)

The intake tube for the K&N filter is a 90 bend. Your loosing alot of flow there, and also creating intake turbulence which slows the natural tuning of the intake to the head. I would says a good 15hp at the top end you would gain by smoothing that part out.


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## morepower2 (Apr 19, 2002)

510Mods said:


> The intake tube for the K&N filter is a 90 bend. Your loosing alot of flow there, and also creating intake turbulence which slows the natural tuning of the intake to the head. I would says a good 15hp at the top end you would gain by smoothing that part out.


Not 15 hp, maybe a couple.


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## FiredragonCT (Sep 1, 2004)

510Mods said:


> The intake tube for the K&N filter is a 90 bend. Your loosing alot of flow there, and also creating intake turbulence which slows the natural tuning of the intake to the head. I would says a good 15hp at the top end you would gain by smoothing that part out.


Hi - As stated above I have tried various arms - even mounting the filter directly in the TB - rounded arms and various angles - but for some or other wierd reason (suppose its to do with the turbulance) this is really the pipe that gives the best results....


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## 510Mods (Feb 21, 2005)

True, some things are pretty strange on how motors like certain things.


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## FiredragonCT (Sep 1, 2004)

Hey guys - heres some good news!

Went onto Jenvey site and found out I need 35mm ITB's for my application (With butterfly 200mm from the valve) so I went looking for some GSXR 1000 ITB's as the Honda guys use - turns out they are 42mm (Same as RSI Toyota ITB's) so still too big and I can pick up a set here for R2000 - ($350)

Then I shopped a bit more and found a set of GPZ1100 ITB's for the ridiculously low price of R250 ($40)!! And guess what - 35mm!!

Whats more is the Nissan (Datsun) 280ZX Injectors fit perfectly into them!

With the Dastek Unichip I have fitted I should be able to regulate the fueling perfecly - I just need to see if I can transfer my TPS (Throttle Position Sensor) or if I need to re-program my management system to accept the new parameters. 

Instead of modifying my Existing intake manifold I should be able to manufacture one for $100 - So it looks like this little project could work out around $300 - not too bad really!

Only problem that I have left is connecting the vacuum lines - any ideas on this? Is there any way I can adapt an electrical vacuum pump - I want to do an electrical water pump as well.

Any idea where I can get a universal fuel rail that I can drill to feed the new injectors and spacing?

Will post pics of the ITB's as soon as I have gone to pick them up...


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## FiredragonCT (Sep 1, 2004)

Hey Guys - Got the ITB's today - here's some pics

I will have to re-use the original Injector positions on my intake or try and manufacture a new intake with injector positions - any clues on the vacuum lines?




























Let me know what you think!


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## himbo (Sep 20, 2003)

wow... thats uber swank :thumbup:


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## FiredragonCT (Sep 1, 2004)

Thanks Himbo!

Will hopefully get my hands on a second hand intake manifold the weekend - will keep posting pics as the project continues...


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## himbo (Sep 20, 2003)

kinda makes me wonder about getting one set up on a b14 GA16... have it setup up like the GTI-R motor, ITB w/ turbo, that would be a killer combo

but how...


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## FiredragonCT (Sep 1, 2004)

You could run the ITB's into an Airbox - Like they do on the bikes - fit a filter and merely let your turbo blow into the airbox...

Not impossible but will take lots of custom work


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## shift_of_legend (Jun 2, 2004)

So are going to have to weld the bike ITB's to your intake manifold flange, so you can bolt back to OEM point? Are you going to remove your throttle linkage rotor and attach it to the ITB throttle linkage point and use your original TB and keep the butterfly valve fully open? That or remove the butterfly valve all together. You'd have to keep the OEM TB since the AFM is built into it right?


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## shift_of_legend (Jun 2, 2004)

I hope this helps
http://members.iinet.net.au/~rospen/projects/quadgti.asp


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## FiredragonCT (Sep 1, 2004)

Thanks Shift Of Legend - that looks like exactly the same ITB's Im using!

The original plan was to make up a custom manifold (Aluminum) but that was before I got hold of the ITB's and thought they had their own injector positions. 

Now the plan is to take a standard inteke manifold and cut it short just after the injectors, match some runners onto it and wels some flanges. Flanges will also be added to the TB's - so they bolt onto the intake with the help of a gasket to seal it nicely.

This way I use my standard injectors.

For the Throttle Position sensor I will either cenvert the stock one to fit onto the ITB position or use the Bike Throttle position sensor - It seems I can tune my Dastek Unichip to work with these Voltages.

Then it should hopefully just be a case of bolting on and a bit of tuning.

Lastly I will either manufacture an air box that sits flush with the scoop on my bonnet for nice fresh air or simply get some 60 degree trumpets that end under the scoop on my bonnet - in this case I will be using the rally sock filters on the trumpets.

It seems that there is a little link on the ITB's that I can use for the Brake Booster vacuum line - I will be making use of all 4 combined instead of just one - ensuring a balanced flow of air - just need to see if it will be suficient for heavy braking on the circuit.

Otherwise I will consider installing an electrical Vacuum pump - does anyone know of these?


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## FiredragonCT (Sep 1, 2004)

OK guys I know its been quite some time - but heres the progress!

Tubes all cut to the correct length - fuel rail and injectors fitted as well as Fuel Pressure Regulator...



















Still has the temporary trumpets on...

One extra water line still needs to be added as well as the brake booster vacuum lines...


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## himbo (Sep 20, 2003)

WOW thats looking really great!!! :thumbup: 

powdercoat and chrome the biatch :thumbup: :cheers:


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## FiredragonCT (Sep 1, 2004)

Thanks! :thumbup: 

Will first fit them and test them - sort out all the bugs and the look at the cosmetics...


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## himbo (Sep 20, 2003)

FiredragonCT said:


> Thanks! :thumbup:
> 
> Will first fit them and test them - sort out all the bugs and the look at the cosmetics...


of course, thats the way to be, GOOD LUCK!!!!


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## FiredragonCT (Sep 1, 2004)

Thanks again - will post power figures and dyno charts as soon as Im done - as well as updated pics...


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## FiredragonCT (Sep 1, 2004)

Well - I went and did it - suprising results!

First I took an old intake manigold (off the GA16 motor) and cut off the tubes a very short distance from the intake itself...

Next I had 4 runners made up to get the spacing right for the ITB's...



















Some of the water jackets had to be slightly modified....










I chose to use the ITB's off a GPZ 1100 Kawazaki (35mm)










Silicone hose was used to link the ITB's to the intake manifold...










A Custom Stainless steel air-box was made up for me by Lizzard Engineering - thanx Dion!










All the brake vacuum lines were summated to supply adequite vacuum for the brake booster










So the assembly begins:




























The standard Nissan Throttle Position Sensor was modified to fit and function with the Kawa ITB's










And there we go - all done!










In the end I had to settle for a different air filter due to space restrictions.

I removed the Dastek Unichip and fitted the Perfect Power SMT6 - allthough the car started up and ran without any chip - Primary mapping is deen but still needs lots of balancing and dyno tuning!

Will keep this post updated but for now this is what the setup looks like!


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## wes (Apr 30, 2002)

VERY cool setup! I do have a few questions and concerns though. The plenum seems rather small, can I ask why you even chose to use a plenum? Obviously the MAF is no longer in the picture so why use a plenum at all? I would love to see dyno charts with and without the plenum. 

Let us know how the tuning goes! And great job on something completely different.


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## FiredragonCT (Sep 1, 2004)

wes said:


> VERY cool setup! I do have a few questions and concerns though. The plenum seems rather small, can I ask why you even chose to use a plenum? Obviously the MAF is no longer in the picture so why use a plenum at all? I would love to see dyno charts with and without the plenum.
> 
> Let us know how the tuning goes! And great job on something completely different.


Well - The MAF is still in the picture - thats the short answer! The second reason is that I will be adding a Supercharger to the setup shortly - so this makes things ready for the boost - whole setup should handle up to 3 BAR boost easily - but only going to run 0.6 bar boost.

The MAF sensor was a short term answer to a long term problem, but should shortly be replaced with a 2.5 bar MAP sensor - then I will try running with the velocity stacks. 

Problem is that with the space available to me the stacks would be rather short, and I would be losing torque, and the would have to be replaced in any case when the charger is fitted....

If you look at the plenum - right before the filter and against the firewall is the MAF sensor.

Will update Dyno charts next week - car will get final tuning on Friday...


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## wes (Apr 30, 2002)

FiredragonCT said:


> Well - The MAF is still in the picture - thats the short answer! The second reason is that I will be adding a Supercharger to the setup shortly - so this makes things ready for the boost - whole setup should handle up to 3 BAR boost easily - but only going to run 0.6 bar boost.
> 
> The MAF sensor was a short term answer to a long term problem, but should shortly be replaced with a 2.5 bar MAP sensor - then I will try running with the velocity stacks.
> 
> ...



OHHH, I see that you incorporated into the hard pipe. Cool. Anyway the bottom end is also built to handle 3 BAR?


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## FiredragonCT (Sep 1, 2004)

wes said:


> OHHH, I see that you incorporated into the hard pipe. Cool. Anyway the bottom end is also built to handle 3 BAR?


Unfortunately not - I would have to seriously lower the compression ratio to achieve that!

But at this stage it seems she will quite safely and happily run on 0.8 to 1 bar boost - although I am only planning on going 0.6...


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## pimpride (Mar 28, 2005)

Man that is so awesome. So a supercharger? Why not go turbo?


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## FiredragonCT (Sep 1, 2004)

pimpride said:


> Man that is so awesome. So a supercharger? Why not go turbo?


The racing I do incorporates a lot of low speed manouverability - typically only first and second gear on the gymkhana's - so I cant afford to have any turbo lag if I want it to actually give me an advantage - I need the power from the word GO....


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## pimpride (Mar 28, 2005)

That's cool. What hp did you start out with? And what do you have now?


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## FiredragonCT (Sep 1, 2004)

pimpride said:


> That's cool. What hp did you start out with? And what do you have now?


I started with about 54Kw on the wheels - This is about 72WHP and about 87BHP

I am currently sitting on 78Kw at the wheels - This is 104WHP and 126BHP

This was all befor the ITB's - it is being mapped today and will be on the Dyno the whole day - so I will have new figures on Monday to post - quite exited!


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## stone (Jul 7, 2005)

FiredragonCT said:


> I started with about 54Kw on the wheels - This is about 72WHP and about 87BHP
> 
> I am currently sitting on 78Kw at the wheels - This is 104WHP and 126BHP
> 
> This was all befor the ITB's - it is being mapped today and will be on the Dyno the whole day - so I will have new figures on Monday to post - quite exited!


Dyno the whole Firday? Don't you need to work?


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## FiredragonCT (Sep 1, 2004)

Ha ha - yeah - I am at work - dropped my car off last night - they are starting on it at 9 and I will be picking it up this afternoon after work - hopefully they are done by then...


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## stone (Jul 7, 2005)

Please let us know the result~!! :cheers:


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## pimpride (Mar 28, 2005)

Damn that is a big jump! You have more whp then I do lol.


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## FiredragonCT (Sep 1, 2004)

Hey guys!

WOW! What a difference now that its properly set up! Hopefully I get the works scanner up and running again today to post the graph!

I removed the rev limiter override - wish I never did - cause now she is only revving 6800 again... But on the up side she used to make 77Kw @ 7700RPM - now she is making 82Kw @ 6800RPM!

Biggest increase was in torque - Peak shifted from 110Nm to a whopping 128Nm! The biggest gain is at 5400RPM - jumped from 103Nm to 124Nm!

Kw right through the range is hugely higher - and the peak increase of 5Kw does not reflect truly due to the lower revs - judging by the angle of curve I should get her to 87Kw easilly if I get her to rev back up to 7700RPM!

The Kw gain through the rev range is between 7 to 13 Kw.... 

As I said - will post Dyno sheet as soon as possible...


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## wes (Apr 30, 2002)

FiredragonCT said:


> Hey guys!
> 
> WOW! What a difference now that its properly set up! Hopefully I get the works scanner up and running again today to post the graph!
> 
> ...



109.9 HP and 94.4 lb ft. 

Power is good and while the TQ gain is good rom your previous dyno it seems low overall. 

Nice job on something completely different!


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## FiredragonCT (Sep 1, 2004)

Hi there - thanks!

Yeah TQ is a bit low - but do remember that it is the GA14 - a 1400cc Motor - so TQ is really difficult to add to this motor...

Oh yeah - its 82KW At the wheels - ie 109WHp and 134 BHp! :hal:


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## pimpride (Mar 28, 2005)

Well someone just posted this in another thread, and you look resourceful enough to get something like this done:

http://www.nissanforums.com/showpost.php?p=998498&postcount=13


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## FiredragonCT (Sep 1, 2004)

Well - cool idea in theory - but unfortunately his idea is slightly flawed...

By changing the contod length he is merely playing with the compression ratio - by adding the inch to the bottom end as well he is merely negating all his efforts again and both his dispacement and compression ratios remain the same.... An easier answer would be to change the crank - that way he can change the displacement.

I have looked into this in the past - the GA16 and GA14 cranks are interchangeable - but the pistons will need to be skimmed to keep them from hittinh the head...

But all you are then doing is creating a Ga16 motor - and I am trying to build the strongest possible GA14...

Thanks for the link anyway - interesting reading...


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## FiredragonCT (Sep 1, 2004)

Here is the long awaited Dyno sheet!


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## shift_of_legend (Jun 2, 2004)

FiredragonCT said:


> Well - cool idea in theory - but unfortunately his idea is slightly flawed...
> 
> By changing the contod length he is merely playing with the compression ratio - by adding the inch to the bottom end as well he is merely negating all his efforts again and both his dispacement and compression ratios remain the same.... An easier answer would be to change the crank - that way he can change the displacement.
> 
> ...



so what if you do it the other way around. What if you use the ga14 crank in the ga16de motor? Will this lower compression well enouh to turbo?


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## kobel4k3r5 (Nov 19, 2005)

that's loving to the eyes...


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## FiredragonCT (Sep 1, 2004)

@ Shift_of_Legend

Theoretically yes, I have not calculated what the exact compression ratio change would be - because before you do this you need to keep the following in mind - The GA14 has a 73.6mm bore and the GA16 has a 73mm bore. Keeping the original conrods and changing the crank to a GA14 you will not only be dropping the compression ratio, but also the engine capacity...

The GA14 crank causes a lower volumetric displacement due to the shorter movements of the piston - and according to my calculations you will end up with a motor with a stroke of 81.8mm , bore of 73mm and engine displacement will only be 1370cc's - I also think the compression ratio will drop perhaps as low as 8:1

So Turbo it will handle and it will sure rev a lot! But will it be worth it to sacrifice over 200cc's - probably not...


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## FiredragonCT (Sep 1, 2004)

Just did another interesting calculation on the GA16 motor - If you want a compression ratio of 8.5:1 for turbo and NOS applications - simply have a thicker headgasket made up - preferrably copper or Stainless steel.

The new Headgasket needs to be EXACTLY 1.49mm thicker than the stock headgasket (When compressed) This has the added benefit of not having to use stretch bots when fixing the head as the headgasket cannot compress anymore and normal high tensile steel bolts can now be used. Also no need to torque the head after a couple of miles again.

Stainless steel headgaskets are also re-usable. But bear in mind both the sub-assembly and head need to be 100% straight and these surfaces needs treatment with copper spray prior to fitment of the gasket.

These gaskets cost about R900 ($150) to have made over here and is well worth the money as they are only a little bit more expensive than the original factory item.


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