Injector Housing Question

[-=Jeff=-]

will injectors housings from a 93-95 fit a 90?

what is different on them?

also how about the plenum?

[Locobob]

will injectors housings from a 93-95 fit a 90?

what is different on them?

Yes but you'll have to switch to the late style primary injectors - o ring seal on the injector rather than the housing.

also how about the plenum?

Yes again with a few alterations. Block off EGR, change a few vacuum fittings, etc.

[-=Jeff=-]

Yes but you'll have to switch to the late style primary injectors - o ring seal on the injector rather than the housing.



Yes again with a few alterations. Block off EGR, change a few vacuum fittings, etc.

Okay so the 93-95 IH with a 90 Plenum would work?

I assume you can smooth out more? or less with the 93-95 IH when porting?

[Locobob]

Okay so the 93-95 IH with a 90 Plenum would work?

I assume you can smooth out more? or less with the 93-95 IH when porting?

The early castings are better for porting since the o-ring for the primary injectors is high in the housing hence the boss can be pretty much eliminated.

[-=Jeff=-]

The early castings are better for porting since the o-ring for the primary injectors is high in the housing hence the boss can be pretty much eliminated.

Makes more sense now.

is the OE Dia of the 93-95 bigger Dia then the 90-92? (not counting the injector boss)

[Locobob]

Makes more sense now.

is the OE Dia of the 93-95 bigger Dia then the 90-92? (not counting the injector boss)

The late castings have a larger diameter due to additional machining by the factory, 34mm vs 33mm approx. This extra machining does not go all the way through the port however - only about 2in down from the top.

[-=Jeff=-]

So if you were able to get a spare set of IH (assuming they are avail)

which would you choose? these would be ported before use

[phrogs]

So if you were able to get a spare set of IH (assuming they are avail)

which would you choose? these would be ported before use

I have a spare set of 90 injector housings!:thumbsup:

[Locobob]

So if you were able to get a spare set of IH (assuming they are avail)

which would you choose? these would be ported before use

If you switch housing styles you will need to buy 8 new injectors so I'd stick with what your car came with. If that is not an issue - say you were going to buy new injectors anyhow - I'd go with the early style for porting purposes. One other note... if you have a late car and switch to the early style injector housings you will need to either grind off the alignment tabs on the heads (2 each) or drill the injector housings to accept the tabs.

[-=Jeff=-]

So if you were not going to port would the later housings be better?

I have injectors so that is not an issue.

[bradslt5]

i stay with the early ones for the o ring placeent being higher up to be able to ake more of that boss out .jmho

[-=Jeff=-]

i stay with the early ones for the o ring placeent being higher up to be able to ake more of that boss out .jmho

Right, but if you were NOT going to port them meaning stock for stock

which would you use?

[rkreigh]

late ones flow better unported due to the injector boss being reduced.

but keep in mind the port match might not be that great, the later manifold and injector housing alignment improved a bit over the early port matching. not an issue if you port and port match, but something worth checking.

early manifold to injector housing alignment wasn't always that great.

I like the late model injectors way better, they tolerate the alchy in the gas vs the early ones breaking down over time.

decisions, decisions.....:mrgreen:

[Aurora40]

I like the late model injectors way better, they tolerate the alchy in the gas vs the early ones breaking down over time.
You can easily use the later injectors in the early housing though.

Why would anyone need a spare set of unported housings though? I'd think the only reason might be originality, but then you'd want ones of the same type (early or late).

[rkreigh]

You can easily use the later injectors in the early housing though.

Why would anyone need a spare set of unported housings though? I'd think the only reason might be originality, but then you'd want ones of the same type (early or late).


good point!! common switch which is a good idea. I also agree with Jeff that cleaning the injectors often isn't a good idea. especially the early ones.

folks seem to have good luck with the accel, and they are cheap!

[-=Jeff=-]

You can easily use the later injectors in the early housing though.

Why would anyone need a spare set of unported housings though? I'd think the only reason might be originality, but then you'd want ones of the same type (early or late).

Ah why would I need a spare set??

Lets say I wanted to be able to DRIVE my vette this summer and also be able to WORK on porting, without the extra set I could not do that.

RK,

If I used later IH I would also use a Later Plenum

[Paul Workman]

Ah why would I need a spare set??

Lets say I wanted to be able to DRIVE my vette this summer and also be able to WORK on porting, without the extra set I could not do that.

Jeff, mebby we need to establish a plenum/IH/head exchange so one could do as you say- P&P "the works" w/o loosing more than a w/e, perhaps of down time. "Have die-grinder, will travel!":wink:. (I guess the fly in the ointment following a head porting would be timing the cams: can it be done correctly IN THE CAR, or is that defenately gonna need the engine pulled? (I dunno))

P.

[-=Jeff=-]

Jeff, mebby we need to establish a plenum/IH/head exchange so one could do as you say- P&P "the works" w/o loosing more than a w/e, perhaps of down time. "Have die-grinder, will travel!":wink:. (I guess the fly in the ointment following a head porting would be timing the cams: can it be done correctly IN THE CAR, or is that defenately gonna need the engine pulled? (I dunno))

P.

I am actually covered.. I have pieces for a swap, just need the nice weather now

[Aurora40]

Ah why would I need a spare set??

Lets say I wanted to be able to DRIVE my vette this summer and also be able to WORK on porting, without the extra set I could not do that.

RK,

If I used later IH I would also use a Later Plenum
Well, specifically why would one want a spare set that they were not going to port. If you will be porting, it makes plenty of sense. One of your follow-up questions was what extra set would people get if they were not going to port it. Seemed like an odd scenario to me. :)

[-=Jeff=-]

Well, specifically why would one want a spare set that they were not going to port. If you will be porting, it makes plenty of sense. One of your follow-up questions was what extra set would people get if they were not going to port it. Seemed like an odd scenario to me. :)

my thinking:

I need to replace the plug wires on my car, I also want to drive it this spring. SO if I put the later IH and plenum on my car for now in OEM form, I will get a slight bit MORE power because they have bigger ports.

Then port my OEM stuff and next winter install it for the following year and be done, then either sell or hang on to the later stuff

[blackjack]

i have a spare set of ih & plenum from a 90...email me if interested
bj
hdrperformance@yahoo.ca

[Locobob]

So if you were not going to port would the later housings be better?

I have injectors so that is not an issue.

As is the late style plenum and injector housings will make a bit more power (10hp range) due to the smaller primary injector bosses and slightly larger runners.

[-=Jeff=-]

As is the late style plenum and injector housings will make a bit more power (10hp range) due to the smaller primary injector bosses and slightly larger runners.

That was my thinking as well