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-   -   Quick question 305cc injectors + vortech 12:1 disk (https://www.miataturbo.net/diy-turbo-discussion-14/quick-question-305cc-injectors-vortech-12-1-disk-18362/)

medisyn 03-16-2008 01:26 AM

Quick question 305cc injectors + vortech 12:1 disk
 
Hi I was thinking of throwing in these 305cc injectors I have had sitting around for years. Would it be bad to run it with a vortech 12:1? Doesn't fuel pressure pretty much max out at 80 psi? Is it a better idea to drop down to a 6:1 disk? If so how boost from a greddy turbo is safe with those injectors?

EDIT: I know my sig says I have a begi afpr but I got it from andy floyd a long time ago. Who knows if it even works...

olderguy 03-16-2008 02:45 AM

On a stock pump in good shape it will max out at 80 psi.

mike_671 03-16-2008 04:42 AM

^ so does that mean that combo would work if the pump is putting out 80 psi

medisyn 03-16-2008 07:12 AM


Originally Posted by olderguy (Post 228623)
On a stock pump in good shape it will max out at 80 psi.

Yeah this was my real question. Would not changing the disk (and using the stock fuel pump.) and using those injectors be safe at 8-9 psi with an open exhaust?

mike_671 03-16-2008 07:47 AM


Originally Posted by medisyn (Post 228632)
with an open exhaust?


noo i dont like open its just way to loud

olderguy 03-16-2008 09:38 AM

With the 12:1 you will be rising rich and running rich until you reach a boost level that would be lean. At 8~9 psi you would probably still be very rich, since you can do 8psi with a 12:1 and 1.8 injectors.

I would put in the injectors, the 12:1 disc, take along a set of smaller discs and go to a dyno that will allow you to swap lower and lower until reaching a nice AFR at your peak boost level.

This is the long way of saying you would probably be very safe at 8~9 psi and the 12:1, but your cat might not and you won't be at maximum power.

medisyn 03-16-2008 08:36 PM


Originally Posted by olderguy (Post 228652)
With the 12:1 you will be rising rich and running rich until you reach a boost level that would be lean. At 8~9 psi you would probably still be very rich, since you can do 8psi with a 12:1 and 1.8 injectors.

I would put in the injectors, the 12:1 disc, take along a set of smaller discs and go to a dyno that will allow you to swap lower and lower until reaching a nice AFR at your peak boost level.

This is the long way of saying you would probably be very safe at 8~9 psi and the 12:1, but your cat might not and you won't be at maximum power.

Ok this should be what I need right?
http://store.summitracing.com/partde...5&autoview=sku
This comes with all the disks?

EDIT: The cat's condition will not matter. I am going to run just a downpipe haha. I am going to the 1/4mi track with a few 400+ hp v8's and they will be far louder than my car on the ride over there. I just wanted to run more boost because its no fun to go all that way and run a 15.5....

rotaryjunky 03-16-2008 08:58 PM

Do you have a fuel pressure gauge to check your fuel pumps health? You really need a 190hp walbro if you plan on staying band-aid. Shockingly easy to install.

rotaryjunky 03-16-2008 09:00 PM

Install the Begi, why play with the disks? Can you borrow a wideband?

FHS 03-16-2008 09:19 PM

Yeah, at the very least, see if the BEGi is working and get yourself a higher output fuel pump. I stubbornly messed with the Vortech and disks for a couple of years and had to have 2 fail on me before I dumped it altogether. The BEGi is well worth the effort to see if it is working.

rotaryjunky 03-16-2008 10:33 PM

Just make sure to have two or more one way check valves installed on the BEGI. Really helps flatten out the AFR curve. You can also send it to Bell and they will rebuild it for you for the cost of the parts. Do it right, do it once.

medisyn 03-16-2008 11:48 PM

OK thanks guys for the advice. I never really used the begi becuase when I got it, it looked really ghetto. I only payed 50 bucks. Here take a look at it.

http://img182.imageshack.us/img182/372/img0566qw1.jpg . As you can see the top bolt is larger. The top was retapped at some point. One of the nozzles on the side looks like it was jbwelded into place. You think its worth taking apart and getting a look at the insides?

EDIT: this thing looks nothing like the AFPR's on begi's website. Maybe its a real old one or a fake?

medisyn 03-17-2008 01:31 AM

Ok I took the thing apart here are the pictures.

http://img150.imageshack.us/img150/510/img0567bm9.jpg

http://img147.imageshack.us/img147/7318/img0568uc2.jpg

http://img167.imageshack.us/img167/7294/img0572og3.jpg

It seems to be in ok shape, maybe with some new diaphragms it would work fine? What else is needed to get it to work? A needle valve?

medisyn 03-18-2008 04:14 PM


Originally Posted by medisyn (Post 228950)
Ok I took the thing apart here are the pictures.

http://img150.imageshack.us/img150/510/img0567bm9.jpg

http://img147.imageshack.us/img147/7318/img0568uc2.jpg

http://img167.imageshack.us/img167/7294/img0572og3.jpg

It seems to be in ok shape, maybe with some new diaphragms it would work fine? What else is needed to get it to work? A needle valve?

Well since nobody posted I just asked BEGi. They did tell me that it was indeed an old begi apfr and that they would fix it up for 30 dollars+ shipping. I got it from andy for 50 bucks so for around 80 thats a fine deal. Screw the vortech then ha ha.

kevin02 03-18-2008 05:50 PM

Let me know how the install of the 305's goes.

I have a similiar setup to you and also have 305's and rx7 afm to install.

Just gotta do my clutch first.

Oh I'm local too, Sunnyvale.

medisyn 03-18-2008 08:03 PM


Originally Posted by kevin02 (Post 229767)
Let me know how the install of the 305's goes.

I have a similiar setup to you and also have 305's and rx7 afm to install.

Just gotta do my clutch first.

Oh I'm local too, Sunnyvale.

Cool, I will do but I am so damn broke right now I will even have to wait to spend the 30 bucks. Ha ha. IM me if you want to talk on AIM or something.

kevin02 03-19-2008 01:19 PM

No worries, I'm in no rush, I prolly won't put my clutch in till Memorial Day, hopefully I can install my wideband by then as well.

I've actually had the 305's and rx7 afm over a year.


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