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720 secondays with nothing to control them???

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Old May 19, 2005 | 01:18 PM
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Question 720 secondays with nothing to control them???

Im taking my car into get the OMP lines fixed next week, so I was thinking of having 720 secondarys put on since he will already have the UIM off, I have a FD fuel pump and a Bosch FPR. My question is the guy Im taking it to is 3 hours away, Im planing on getting a Rtek 1.7 but not for a couple weeks, what would happen if I got 720's and had nothing to control them???
Thanks
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Old May 19, 2005 | 01:28 PM
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really really really really rich, aka, your likely to kill a moose, or a Godzilla. You might end up flooding your car too, he. You wont want to drive it much at all. As long as you keep them off line (below when they turn on, hahahaha) then you'll be okay.
edit*the FPR will help a bunch
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Old May 19, 2005 | 01:35 PM
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It will run rich but it wont flood im running 720P and 720S on a stock ecu and my car runs fine no BS. The engine is stock turbo is not. Im also runing MSDs
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Old May 19, 2005 | 02:28 PM
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Also will I want high Imp. or low Imp.??? whats the differance???



Originally Posted by BUMBLEBEE7
It will run rich but it wont flood im running 720P and 720S on a stock ecu and my car runs fine no BS. The engine is stock turbo is not. Im also runing MSDs

What turbo are you running???

Last edited by josh greene; May 19, 2005 at 02:53 PM.
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Old May 19, 2005 | 03:20 PM
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high = S5
low = S4
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Old May 19, 2005 | 04:22 PM
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I ran 720s without fuel control for a while. Wasnt as bad as everyone makes it out to be.
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Old May 19, 2005 | 05:50 PM
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Well, if you do get it to run then you'll need to buy something to tune those *****! I don't see how it would hurt but you'll get horrible gas mileage probably.
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Old May 19, 2005 | 05:58 PM
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well Im planing on getting a Rteck chip in a couple weeks but I just figured if the UIM is off It would be easyer to stick them on rather then taking it off again.
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Old May 19, 2005 | 06:20 PM
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Originally Posted by Kingsfan
high = S5
low = S4
That is not correct. Cars made in June of '87 that have the last 4 digits of the VIN as 7601 or higher are HIGH impedence injectors. So all the '86 cars, and half of the '87 cars have low impedence injectors, the rest of the '87 through '92 cars have high impedence injectors.
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Old May 19, 2005 | 06:21 PM
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From: el monte, spanish for...the monte
ok, so not entirely accurate
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Old May 19, 2005 | 06:31 PM
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Ok well I was looking at some gready ones on the forum and the guy says theres a way to change it from low to high???
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Old May 19, 2005 | 07:47 PM
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You will drive fine with 720 secondaries and no fuel control. Almost all injectors 720cc and larger are low impedence. Find out what impedence your car has stock and with that information you will know whether or not you need resistors. Do a search everything you want to know about resistors has been posted already.
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Old May 19, 2005 | 08:31 PM
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you shouldn't suffer bad fuel economy, flooding, or any other major nasties at all. The secondary's only function under high load and revs, so you'll just run rich at high load and revs, which isn't particularly bad...
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Old May 19, 2005 | 11:57 PM
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Do it. I did it for a while, and it's not as bad as everybody says it is. It is super rich, though...super rich. Say HEeeeelllLLoooo to fireballs!
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Old May 20, 2005 | 11:32 AM
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Originally Posted by josh greene
Ok well I was looking at some gready ones on the forum and the guy says theres a way to change it from low to high???

http://www.rceng.com/Default.htm

RC Engineering makes 750cc high impedance injectors, anybody have experience with these?
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Old May 20, 2005 | 11:50 AM
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I have the RC Engineering 750cc secondaries, it does run rich, with awful mileage, and I have had flooding - I'm getting an Rtek 1.7 to solve the problems.

No problems with the injectors themselves though.
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Old May 20, 2005 | 01:23 PM
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Originally Posted by vhold
I have the RC Engineering 750cc secondaries, it does run rich, with awful mileage, and I have had flooding - I'm getting an Rtek 1.7 to solve the problems.

No problems with the injectors themselves though.

When are you getting the Rtek Chip???
Let me know how it works???
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Old May 20, 2005 | 02:26 PM
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The Rtec is awesome. The ANTIflooding function is awesome, especially if you are trying to break in a new motor like myself. It is deffinetly worth the money. Somebody was telling me that they are going to come out with another version for bigger injectors and datalog capabilities. That will really be sweet...
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Old May 20, 2005 | 02:36 PM
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there comming out with Version 2.0 that is for bigger injectors data loging and other stuff but from what I have heard its gonna be a bit more money, someone said that there trying to keep it under $500.00. but yes it will be sweet!
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Old May 20, 2005 | 08:48 PM
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i want the 2.0!!! That would be sweet, maybe i can hold off without getting a standalone for a while til then!
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Old May 20, 2005 | 09:25 PM
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Originally Posted by C-Murder
You might end up flooding your car too, he.
The secondaries are not used at starting, so increasing their size cannot cause flooding.

You wont want to drive it much at all.
The engine will run richer than normal above 3800rpm, but will still be perfectly driveable.

the FPR will help a bunch
The FPR will not help at all. Reducing fuel pressure to compensate for larger secondaries will cause the engine to run lean below 3800rpm when the aren't used. Don't post bogus info that could kill an engine!

Originally Posted by Blowtus
...you'll just run rich at high load and revs, which isn't particularly bad...
It's pointless in the short term and bad in the long run. Overly rich mixtures simply reduce power and increase fuel consumption. They also increase engine wear due to oil thinning. A couple of weeks is fine but as a permanent thing it's pretty dumb.

Originally Posted by vhold
I have the RC Engineering 750cc secondaries, it does run rich, with awful mileage, and I have had flooding...
Your flooding has nothing to do with those injectors unless they're leaking. Flooding is caused by low compression and/or leaking injectors, not larger secondaries.
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Old May 21, 2005 | 03:02 PM
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NZ I got a question for you. If I have 720cc injectors in primary spot could that be the problem of my flooding with a moderately tuned s-afc.
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Old May 21, 2005 | 03:37 PM
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I'm not hailers but yes that could be causing your flooding problems. The SAFC cannot control the injectors during cranking.
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Old May 21, 2005 | 06:06 PM
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I only really have problems getting it started when its already been warmed up and I shut it off. Then if I go to start it, it floods. It never used to do this until I replaced the starter (my old starter would need the persuasion of a mallet to get it to crank). Sometimes I can crank it and step on the gas right before it fires and it will fire right up.
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Old May 21, 2005 | 08:13 PM
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Originally Posted by SpeedyRotary
If I have 720cc injectors in primary spot could that be the problem of my flooding with a moderately tuned s-afc.
Yes. The ECU doesn't use the AFM for cranking mixtures, it uses a seperate map. So the S-AFC (which intercepts the AFM) can't compensate for cranking mixtures.
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