DIY_EFI Digest Monday, October 25 1999 Volume 04 : Number 602 In this issue: Converting a Performer manifold and TBI to TPI... Re: DIY_EFI Digest V4 #601 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 25 Oct 1999 07:56:52 PDT From: "David Sagers" Subject: Converting a Performer manifold and TBI to TPI... Steve I was trying to do the same thing a while back, the injectors in the Edelbrock TBI to multiport conversion, according to an Edelbrock tech, use a very small voltage or (ohm? can't remember the difference right now) so that the TBI computer which is made to drive two injectors can drive eight injectors without frying the computer or the injectors. I seem to remember that the injectors are smaller in diameter than stock units so they won't fit in a factory GM EFI manifolds. Currently the injectors come in two sizes, about 20 lbs per hr and the larger 29 lbs per hour. Edelbrock says the they successfully run a 502 BBC with the big injectors. The conversion kit includes a card that requires you to give them a lot of info about your engine, cam exhaust, etc... so they can provide the right chip. That is if you engine is stock or pretty close, otherwise they will direct you to someone to make the chip for a bigger cam or what ever you have that is outside of what they will sell over the counter. Liability, emissions and all those other concerns prevent them from selling chips that work with modified engines. If you are really good at drilling you can make jig to hold your manifold and drill it for injectors, then either weld or epoxy in the bungs to hold the injectors. Force Fuel Injection http://force-efi.com/ sells these or you can pay to have Force make the conversion for you, about $600. One thing to consider is that if you are going to use a solid fuel rail all of you injectors must be at the same angle and at the same height. If you look at the runners on a Performer, or any other dual plane intake, intake you'll notice that runners next to the head are various heights. Consider a Edelbrock Torquer intake as all the runners next to the head are about the same height. Even though the Torquer is a mid range RPM intake, the EFI will really tame it down and you'll have some very strong low end power and throttle response. About a year ago I read an article in a 4 wheel magazine that described using a Torquer converted to EFI on a rock crawling jeep. The bottom end power was very strong as the EFI does not depend on air flow to draw the fuel out of the carb. If you use the Performer, consider making your ow fuel rails/lines out of some high pressure fuel line. Another option is something I saw in the PAW catalog. I think it was a Weiand intake that is made to be converted to EFI. It has the pads and the fuel rail towers cast in and would save you a bunch of time and money. You'd still need to drill and weld the injector bungs. Cost is about $250 from PAW. Date: Sat, 23 Oct 1999 00:03:51 -0400 From: "Stephen R. Cauffiel" Subject: Converting a Performer manifold and TBI to TPI... Hey guys, I think I remember a thread recently (here or on the Third gen list) about drilling an Edelbrock Performer manifold for TPI injectors and running a TBI with injectors removed as the throttle body... Am I smoking crack? I know that Edelbrock has their $2000 version of this, but if I could afford that... This would work with the TBI harness, wouldn't it? You would have to rewire it so that the left injector wiring fired the left bank of TPI injectors, and the right injector wiring the right bank... Has anyone done this? Would it work? If you could burn your own chips/reprogram the computer to compensate for changes... Would this work on a 383 SBC? Please, unless you are going to stroke me a check, don't say "Just buy the MiniRam/SuperRam/HighDollarRam and call it a day." If I could afford stuff like that I wouldn't even be asking this kind of question... Thanks for any help, Steve ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ------------------------------ Date: Mon, 25 Oct 1999 12:37:26 -0400 (EDT) From: William T Wilson Subject: Re: DIY_EFI Digest V4 #601 On Mon, 25 Oct 1999, DIY_EFI Digest wrote: > I have a friend who's trying to get a spec RX7 series running back > home, and would like to have a "spec" rev limiter in the interest of It is difficult to build an ignition based rev limiter for an RX-7 because of the dual ignition system. > reliability. I'm not fully up on the ignition system but there are > two distributors (with points), along with a set of leading and There should be only one distributor on an RX-7. Earlier Mazda cars had two, but the RX-7 should have one that has two sets of points in it. > trailing plugs. My thought is to kill spark to one set of plugs (vs > all of them) to prevent nasty back-fires, while hopefully cutting > power. Backfires (actually afterburn - fire in the exhaust) is okay. Especially in a racing series. Scare your opponents, amaze your friends. The bad news is that either ignition is enough on its own to ignite the fuel and allow you to overrev the engine. You have to cut both ignition systems. Anyway, why do you need a rev limiter? The redline on the RX-7 is only there to give some color to the tachometer. I have overrevved my 1st generation RX-7 all the way to 8500 RPM without damage. (don't make a habit of that. :} ) ------------------------------ End of DIY_EFI Digest V4 #602 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".