240SX TB Mod

[24OZ]

Can anyone explain to me the advantage of changing my stock L28 EFI (280ZX NA) TB with a TB from a 240SX, I hear its bigger but what does that actually mean?? More air into the engine = more power... this is my laymans understanding.

Will I notice alot of difference? Or will the gain only be marginal? I have no other mods on the car apart from a RAM AIR Cone Filter.

If you've done it is it easy to do? Would you recommend this upgrade?

Thanks in advance for your thoughts on this

[sjcurtis]

240Z, I think you are probably enjoying very good acceleration from the standard system anyway if your inlet air ducting is right up front. I was told to head towards 60-65mm plus tb, tb type is open as long as you increase the butterfly size for more air down low but with an annalog airflow meter we are still restricted. I guess its trial and error to overcome the any real airflow shortfalls from the front that are encountered. I have never heard of someone changing back.

I will also be very interested to hear any of the spin on this mod someone must know how to do this properly.

cheers

Steve :classic:

[24OZ]

Hi Steve,

I asked around and this is what I was told:

1.) There will be a noticable increase in your acceleration but in my opinion you could use your time and money elsewhere with better results. In order to get the full benefit from a larger TB you also have to open up the intake manifold to match the opening on the TB. There will not be an increase in hp at any rate. Accelation is the only benefit and a minor one at that.

2.)The acceleration "feel" is better but at wide open throttle there is no change. What that means is that for racing purposes, track runs, and dyno tests you will not see any change. In daily driving what you will see is that you don't have to push the gas pedal down as much as before to get the same throttle response. However when you floor it the air going is will still be the same as with the stock manifold because the smallest part of the intake system is not the throttle body. In order for you to see any real track or dyno results you have to port and polish the head, full port match on the intake manifold, and have the larter throttle body with a better intake filter. Some say just get the throttle body and then port match the intake manifold where it connects. But what about the rest of the intake manifold? The rest of it will still be too small to accept the extra air. Same goes for the head. This mod should be saved for the end once you've done most of the other mods and have port and polished the head and fully port matched the intake manfiold. Even then you will probably only see about a 5hp difference as L28 engine already breaths pretty well with the stock throttle body. Save the money for other mods that are worth it.

[sjcurtis]

240Z

I think you have really hit the nail on the head with the package low HP change for the small change.

I opened the front of my airfilter housing up to assist with free flow thru the standard 280 paper elememt fillter and housing. I really get a good air flow acceleration with significant reduction in restriction over the standard 280Z config ( read "roars like demon when serious RPM is applied"). I have allready got the high flow/match ported intake and plemmum runners with Hemi combustion chambers on mine and the mid range to high range operating mileage is very good. I think a healthy airflow meter and good un-metered airflow management helps though.

I am still interested in about a 65 mm TB as I am operating the twin butterfly model it is not that bad, but I would like better.

Cheers

Steve :classic: