2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

is it possible to tap some injectors in a greddy TB elbow?

Old Apr 18, 2004 | 12:08 PM
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is it possible to tap some injectors in a greddy TB elbow?

just got a greddy elbow and i know that some old elbows have injectors in them..i would like to know if its at all possible to put some injectors in the elbow i have..if theres a how to on this that somebody knows about please give me the info on the site..


thanx alot for any info
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Old Apr 18, 2004 | 08:52 PM
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Not recommended on the "new style" TB adapter - the cast aluminum is too thin.

There are optional places on the stock intake manifold which are stronger / better.


-Ted
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Old Apr 18, 2004 | 09:21 PM
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calio,

I have a TII upper manifold that has two injector bungs welded into it. Very nice looking. I used it when I had an AIC III. I'd be willing to let it go it you're interested.

I'll try to get pics up tomorrow, if you like.

Reese
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Old Apr 18, 2004 | 10:20 PM
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im actually in the middle of the fd UIM swap is it posible to do something with that?


thanx
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Old Apr 19, 2004 | 12:20 AM
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Don't use additional injectors. The controllers are crude at best and EFI manifolds are designed to carry only air, not an air/fuel mix. Get bigger injectors instead.
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Old Apr 19, 2004 | 12:42 AM
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Originally posted by NZConvertible
Don't use additional injectors. The controllers are crude at best and EFI manifolds are designed to carry only air, not an air/fuel mix. Get bigger injectors instead.
what he said
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Old Apr 19, 2004 | 02:51 AM
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EFI manifolds are designed to carry only air, not an air/fuel mix.
IT's an odd thing that mazda put our secondaries smack in the middle of the intake manifolds, huh? I'd bet they know a few things we don't.

Get bigger injectors instead
In general, yes. BUt what if you only need 5-10% more fuel for top end or safety? Why spend $2-400 for a set of injectors, when you might already have a set of small stockers (or smaller stockers off another car that could work) that would do the job for free?
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Old Apr 19, 2004 | 03:03 AM
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Originally posted by NZConvertible
Don't use additional injectors. The controllers are crude at best and EFI manifolds are designed to carry only air, not an air/fuel mix. Get bigger injectors instead.
I know you're not a fan of AIC's, but honestly I believe they're just as usable as a safc. All the safc does is adjust the afm signal different amounts, that's not entirely advanced technology either. I'd hardly call a haltech f5 crude.
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Old Apr 19, 2004 | 03:03 AM
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double post
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Old Apr 19, 2004 | 04:13 AM
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Originally posted by RotaryResurrection
IT's an odd thing that mazda put our secondaries smack in the middle of the intake manifolds, huh? I'd bet they know a few things we don't.
They are not in the middle of the manifold, they are most of the way along the intake path. And there is no plenum or throttle body that the fuel/air mix has to pass through. Any time you have a liquid suspended in air and you ask it to rapidly change speed and/or direction (i.e. pass through a plenum or throttle body), some of that fuel will fall out of suspension and condense onto the inside of the manifold or TB. This causes changes and inconsistancies in the mixtures. Plus when you take a fuel air/mix that is never going to be completely homogenous anyway and divide it between four intake runners, there's no gaurantee an equal proportion of fuel will travel down each port.

These phenomenon are well-know and well-proven. They are the reason manufacturers replaced early single-point EFI systems with multi-point systems two decades ago. I know full-well that additional injectors work, I'm just saying they don't work nearly as well as injectors in the factory locations. Injectors added a bit further upstream from the stock injectors are okay (e.g. in the secondary runners), but injectors mounted pre-TB should be avoided at all costs. This isn't rocket science.

BUt what if you only need 5-10% more fuel for top end or safety? Why spend $2-400 for a set of injectors, when you might already have a set of small stockers (or smaller stockers off another car that could work) that would do the job for free?
Free? What are you going to use to control them? Most people resort to an AIC, and even brandname ones like the Haltech F5 are extremely crude devices that have only two adjustments (when and how much) that are made by screwdriver. They have no control of the other injectors, so you will always get a rich spot as they come on, resulting in the same sort of stumble FC owners already go to great lengths to eliminate (the 3800rpm stumble). And they're not free...

An S-AFC is no patch on a proper EMS, but it makes your average AIC look worse than a carb.
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