I'm planning on using this in my 280z. The car is fitted with SDS fuel injection management, stock injectors, stock cam, stock 280Z intake & exhaust manifolds, stock exhaust (no cat). I'm hoping that I will notice some difference in power, but I know gains will likely be marginal due to the restrictive stock equipment and non-modified intake & cylinder head. I'd like to install a set of OEM 280ZX turbo fuel injectors. If switched to the fatter injectors, the mixture can be adjusted with the SDS programmer based on the injector flow rate, so I'm not concerned about fuel/air ratio problems. Any advice...? Thanks

Looks like you've read up on how to make power. Why hope when you don't have to (this could be a campaign slogan!)? You listed all of the stuff that you should work on, so it also looks like you already know it's not going to work.

The injectors and size of the throttle body really only serve one purpose - to supply the fuel and air demands of the engine. Without increasing the demand, with a different cam, or intake/exhaust port work, or exhaust system work, for example, the bigger injectors and throttle body will be wasted. You'll probably feel a difference in throttle response because the same amount of throttle blade movement will let more air in with the bigger body, just like pushing the throttle pedal farther. Basically, you'll have less throttle control that gives a feeling of more power, that's not real.

Just one opinion. I can't recall a single thread or post in which someone said they got more power with bigger injectors and/or throttle body alone. I have read some accounts of people removing the big throttle body because it just made the engine hard to control, but no more powerful. The SDS will probably allow you to reduce injection duration so that it performs like a small injector, so you'll probably get away with that modification without noticing any ill effects.

Not to mention if it is a CA. car you will not pass smog, at least the visual inspection.

It will not improve performance. Read Braap's EFI guide on HybridZ.

I'm planning on using this in my 280z. The car is fitted with SDS fuel injection management, stock injectors, stock cam, stock 280Z intake & exhaust manifolds, stock exhaust (no cat). I'm hoping that I will notice some difference in power, but I know gains will likely be marginal due to the restrictive stock equipment and non-modified intake & cylinder head. I'd like to install a set of OEM 280ZX turbo fuel injectors. If switched to the fatter injectors, the mixture can be adjusted with the SDS programmer based on the injector flow rate, so I'm not concerned about fuel/air ratio problems. Any advice...? Thanks

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I have a friend of mine that put a large throttle body on his Z. The only difference he noticed is that you reach WOT sooner. Since you're using the stock intake manifold there is only so much air you can fit in there. As LeonV mentioned there will be very little if any performance gained.

Jan

A lot of effort for little gain. Im not sure what you want to achieve here?

A set of extractors from MSA, which are now 20% cheaper in their Holiday special, would probably work better and more fuel efficient which would mean no problems with smog regulations.

I'm not concerned about smog. In California, 1975 and earlier model year vehicles are exempt. In any event, I couldn't use the SDS system on a registered motor vehicle if I had to comply with a visual inspection (talk about a waste of money if I had to, the EM4 system costs over a thousand bucks). I've never tried the bigger TWM throttle body on an FI-equipped Z car. I'm not trying to go to the moon, the part was basically free...if I gained anything from this, it would be the knowledge that this mod is probably not worth the money if the part was bought new, but at least it was fun experimenting with something different than stock (I was hoping for more torque). Based on the valuable opinions expressed here, I may hold off on this until I have the time to modify a stock manifold & cylinder head, add a cam & headers, a less restrictive muffler and exhaust, etc.

Edited November 25, 201212 yr by chaztg