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Discussion Starter #1
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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Powered By hopes & dreams
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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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Sorry to ask but what's that thing on the back bumper?
 

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♣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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Icy Hot Stunta
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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.


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.
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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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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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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Icy Hot Stunta
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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 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?
I think the S&B ITB's bolt right to the TWM manifold.
 

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Discussion Starter #9
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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Discussion Starter #11
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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Nis-ho
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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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Discussion Starter #13
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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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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Icy Hot Stunta
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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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Discussion Starter #16
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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True, some things are pretty strange on how motors like certain things.
 

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Discussion Starter #18
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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Discussion Starter #19
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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