Plenum pull veterans I have Q's

Originally Posted by Nick

Yes, you can get a ride after I get done.

[haber rj]

Well gentlemen it looks like I will be taking on the job of installing the new injectors in my 91Z, if all fails and I screw it up I will send for CAA and have it towed to my friends performance shop and have it fixed correctly, he is to busy to do it right now and I can't wait. Thank you for all the help and recommendations, this is my first time talking with other ZR1 owners on the site and I think with all the people who own such a marvellous we are a special breed. Stay close I might (WILL) need more HELP.
haber rj

[Z Factor]

Originally Posted by haber rj

Hello Tom, I am also in the process of replacing all my injectors and with the modification that I have done ( bolt ons, headers, corsa exhaust, new prom) they told me to run 24lb or 257cc injectors. I am not familiar with replacing injectors or the removal of the plenum, but I guess that there is no time like now to get in and learn. It really doesn't look that difficult, taking the upper plenum off should be ok if I take my time.

haber nj

Hello, and welcome to the forum.

I would say that "24lb or 257cc injectors" might be a bit much considering the stock injectors run 220cc/min. I will be addressing Toms question on the matter, and a response or two he has gotten, but in the mean time, reconsider going up to that injector unless there is a sound logical reason to do so.

[Z Factor]

Originally Posted by tomtom72

As a P.S. to all this I just noticed someone else's post about injectors. I purchased RC #205 and it seems I got the wrong ones? It seems I should have bought #225? Any help on this would be great! Thanks again.

You were probably referring to my recommendation about getting the 225cc/min injectors vs. the 205's that you ordered. As Jeff posted, the 205's will be fine for your application, as would the 225's and will not cause any harm. Both have been used by different ZR-1 owners, and it is a matter of splitting hairs as to which is better. Some people actually use the 205's for primaries, and the 225's for the secondaries. Flow rates vary for several reasons, not the least of which is based on the amount of pressure when measuring them. RC uses 43.1psi (if memory serves me correctly) to bench injectors. If you use greater psi, it will have an effect on the final numbers. Strictly speaking, using GM's numbers, the correct injector by RC will be their 225cc/min which is closer to the stock 220cc/min or 21lb injector, which RC would confirm if you were to contact them. However, that is not to say that a 19lb injector which flows at 205 (psi being equal) will starve the engine of fuel. As Jeff said, if you were to mod your LT5 then having the 225's would make sense, so anyone considering that in the future may as well go with the 225's now.

I hope that helps to also ease your mind since I did not want you to be concerned based on my other post. I should have explained it in more detail so there would not be any misunderstandings.

[tomtom72]

Hi & thanks Z Factor for taking the time to hold class!! I may yet get my GED in ZR-1's! Well at least I should pass Plenums 101!

I thank you for helping me out. I have a better handle on the injectors' size now. Yes my motor is box stock & mods are way out of my budget. You hit it on the head as I thought fuel starvation!! I'm happy the way it is & I don't have any trouble keeping up with the other newer corvettes I play with

Another couple of rookie Q's if I may impose on every one's good will. The injectors are a press fit into the fuel rail? I'm trying to figure that out as I've never seen a fuel rail. I understand that the hold down brackets press the rail into the I/H but what holds the injectors into the rail? Just the hold down brackets? The last vette I worked on had a holley!

Also, I went to Samco's web site and tried to look up cooling hoses by application. I didn't find any. Did I miss something?

Thanks again Jeffvette & Z Factor for your help!!
Tom

Tom, when assembling the injectors onto the rail, they are a press fit in. You just insert use a little pressure and twist some. One thing that will help a little is use a little spit on the o-ring itself. Won't harm the injector or rubber. Then when putting rail back ont to the injector housings, there are two methods.

One: get everything aligned up and alternate tightening the 4 bolts for the rail.
Two: Get the bolts started and lightly tap over the rail.

I use method one.

[tomtom72]

"I see" said grasshopper! Thanks Jeff! I've been away for awhile, ahem, holley carbs, yea right I can work on FI!

Bad enough I'm a rookie Z owner but I'm 30 yrs behind on auto technology to boot!

Seriously, thank you & I agree with method #1. I sound like a broken record but you senior members make this possible for us rooks to learn and I thank you guys for that!

Thanks,
Tom

[Z Factor]

Originally Posted by tomtom72

You hit it on the head as I thought fuel starvation!!

Another couple of rookie Q's if I may impose on every one's good will. The injectors are a press fit into the fuel rail? I'm trying to figure that out as I've never seen a fuel rail. I understand that the hold down brackets press the rail into the I/H but what holds the injectors into the rail? Just the hold down brackets? The last vette I worked on had a holley!

Also, I went to Samco's web site and tried to look up cooling hoses by application. I didn't find any. Did I miss something?

Thanks again Jeffvette & Z Factor for your help!!
Tom

I am no expert Tom, but I figured you were concerned and I try to help out when I can.

As to the injectors there are clips. Also the fuel rail has bolts that help seat the injectors into the housing.

As to the Samco question, stay tuned to the Samco Air Duct thread

http://zr1netregistry.com/forum/showthread.php?t=833


because we are about to make a group purchase for the Air Duct and coolant hose kits as well. Samco does not sell to the general public, and the stock for the LT5 is very limited. So since they make everything by hand, there has to be a large enough demand for a production run.

[haber rj]

Gentlemen thank you very much for the much needed information on the injector selections and the istallation method. I am going to be running a 125 shot of NOS and I think that I will go with the 225cc units, One more question if you don't mind are the RC units stainless and are they a good choice or is there another source that would be better, but more money.
haber rj

RC's are stainless, so no corrosion worries. If you are spraying the 225's are your choice.