Hi Guys!

I own a UK spec Honda Jazz - GD1, 1.4 I-DSi engine and at the moment my mods are ARC induction kit, Spoon B-pipe and muffler. I just want to know your opinions on throttle bodies, what gains would I get out of my engine, and which is the better?

My future mods are a T1R racing convertor and a Spoon Manifold. So all opinions are welcome!

Thanks in advance,
Michael

 

i would try just stick with one brand. go with the spoon throttle body if your planning on doing the exhaust with spoon parts too.

 

X2 ^^^^^^^^^^

 

i agree^^^^

 

yep SPOON FTW! =)

 

Haha ! Spoon then?

Yeh i wasn't sure about this modification at first but i believe it is only available to the JDM market as the USDM have different size or whatever? - can someone clear this up! lol

Does anyone know what gains i will get then from the L13A engine? maybe 2-3 BHP?

Thanks!

 

I think it depends of just how big it's in the first place, the displacement of the motor, how high will it rev and what mods you also allready have!! Going from the stock 49mm on my manual transmission DOHC neon (I know it's just a fu**in' dodge for all of you.... :P) to a bigger one from an automatic one (52mm) made a terrible difference... It gained something like 7-8WHP (Lost dyno chart ) The neon allready had a midtube header, a freer exhaust, a Iceman Cold-air intake, reworked intake manifold, AFX-R UDP and a Mopar PCM (Reving to 7800Rpm)... Later on i installed a 57mm throttle body to prepare for the cams and headwork i planned to do but with the mods i had, it didn't made too much of a difference...

Consider than the DOHC engine in a neon is a 2 liter displacement engine making a healthy 150HP by the standards of 1994... Putting a Mopar PCM did increase it's RPM potential by a fair amount (7800 from 7200) as well as leaning the too rich factory fuel trims to 13:1 (From 11.5:1 - 12:1) and giving more timing advance... The header, exhaust, intake manifold port&polish job as well as the cold-air intake increased airflow by a fair amount but became really limited by the stock 49mm throttle... take into account that the engine produced near 170hp with the 49mm throttle and with the 52mm throttle it gave near 180hp...

Think that a 2 liter DOHC 16 valve Neon spinning way over 7k rpm produced near 170 crank HP with bolt ons and a 49mm throttle plate... If the Euro fit have the same throttle body i have in my USDM one (50mm) i dont think you will see too large of a gain from a throttle body as the stock one should flow more then enough air for the smaller, less RPM happy 8 valves I-DSI motor...

Just to calculate what my own fit engine should need...

((Max RPM/2)*Displacement in cubic inches)/1728. so...

((6500/2)*90)/1728 = 169.27CFM per minute! + 10% (Because of overlap, headers, etc...

169.27 + 10% = +\- 190CFM...

49mm TB flows 252 cfm
52mm TB flows 283 cfm
55mm TB flows 317 cfm
60mm TB flows 377 cfm

Technically the stock Throttle body and even the stock airbox opening (44mm) should be more then sufficient for the need of a L15A... In practice however, the stock airbox is full of resonators that kill airflow at higher revs so an intake really helps here...

Hope thil helps!!

Marko!!

 

Excellent! exactly what i wanted! cheers for that Marko! Yeh i am 'intending' to purchase in one of these throttle bodies! another quick question would a cat delete (refering to the J's racing test pipe) make the car backfire? Bearing in mind I've got the Spoon muffler and B-pipe and the B-pipe does have a resonator?

Cheers,
Michael

 

Based on my experience, it should not... but you may run lean sooner or later... if i were you, i would forget the throttle for now and invest on a quality wideband like an innovate and a Adjustable Air Fuel pressure regulator and check if your air-fuel ratios are in check and tune a little if they are not... the problem is that the car's ECU goes in a pre-programmed mode at WOT and use values based on a stock engine's airflow... tuning should give you way more power then a simple throttle body that can screw up your low end torque if too big anyway because of reduced air velocity...

Marko!!

 

USDM throttles are Drive by wire... (ECU controlled!) Yours is more likely cable operated and it's not a bad thing as you're likely to have better throttle response this way...

Marko!!

 

Hmm...okay, do you know anything about exhaust manifold gains then? would that be more of a gain than a throttle body?

I plan to get a Spoon manifold, J's racing delete pipe, plus on top of that i've already got the B-pipe and mufffler. Surely that would give me more hp??

Cheers

 

Personately, i would do the header before the throttle body for sure... They apparently gives 4-5Hp to a Vtec fit... I dunno for a I-DSI engine...

Marko!!

 

I wouldn't upgrade the throttle body unless the motor is internally built.

 

X2 :P (L15A1! I-DSI i could not tell! what's the size?)

Marko!!

 

hmm..okay i beileve the size is 58mm. Is that the same as the L15A? yeh man thanks for the help guys, appreciated!

 

Mine is 50mm... More then enough for a 1.5 liter engine spinning only to 6500Rpm... The stock air box has a 44mm opening so you should gain a lot of top end if you install a cold-air on a L15A1... for the I-DSI, if you have a 58mm (I doubt so...) you allready have a Throttle body more then sufficient for a 500Hp Turbo engine so i really wouldn't change it... :P

What's your redline?

Marko!!

 

I know i doubt that its 58mm as well but im sure thats what it said in one of the threads :~(, anyhoo's it redlines at 5,500rpm!

I notice a bit of difference after the b-pipe and muffler exhaust but mainly its top end, im after more acceleration than anything else.

 

Check this out!!

Honda Fit Power Pages - Import Tuner Magazine

Ehh!! If you Red Line at 5500Rpm and you have a 1.4 liter 8 valves engine, i would think that anything bigger then 40, maybe 45mm would be a waste!! If acceleration is your primary concern, i would buy a good Header...

Marko!!

 

Yeh your right, not worth it for a 1.4 i-DSI i guess, oh well guess i'll be better off with a manifold and test pipe..cheers for the info!

 

No problems!!

Marko!!