2nd Generation Specific 1986-1992 Discussion

720cc in stock tII?

Old 11-04-2006, 11:09 AM
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http://cgi.ebay.com/ebaymotors/Bosch-Type-...1QQcmdZViewItem



thats the ebay link.



are these worth buying for my TII? i want 10psi. i have a fuel cut defender. but the motor is completely stock otherwise.



(oh and homemade crappy small exhaust, kinda)



oh...and its a 91.
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Old 11-04-2006, 11:14 AM
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http://cgi.ebay.com/ebaymotors/2-Mazda-RX-...1QQcmdZViewItem



or maybe these....a little more though



what i really need to know. is, will i benefit from this upgrade?
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Old 11-04-2006, 11:19 AM
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those are rebuilt injectors, thats why they are so cheap.



the ones i got were like 230cc cores...



i did run 550x680 in my t2 and it ran great, its 10% more fuel so if you increase the power by 10% its not a bad idea
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Old 11-04-2006, 11:56 AM
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i was told that its not a good idea to use 720cc secondary injectors in the S5's because you cant adjust the MAF like you can the S4. can the stock ECU can handle this upgrade? i would think so...
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Old 11-04-2006, 01:05 PM
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well is that a good upgrade??





yes and no.... on the positive side you will run too rich and you will not lean out and blow up!



but the down side if u dont have an safc or somethign to tune them down, you will probably be running too rich and it will hesitate and bog down and not make that great of power and stuff above 3800 rpm





if i were you id buy 720 cc injectors then purchase a used SAFC1 or SAFC2 then have it tuned on a dyno for an hr. and it should be all set
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Old 11-04-2006, 01:10 PM
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if you have a 91 rx87 be sure to get oval conector and HIGH impedance injectors
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Old 11-05-2006, 04:33 PM
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Originally Posted by sen2two' post='843942' date='Nov 4 2006, 09:56 AM

i was told that its not a good idea to use 720cc secondary injectors in the S5's because you cant adjust the MAF like you can the S4. can the stock ECU can handle this upgrade? i would think so...


i didnt make any adjustments to mine, and it ran fine. part throttle, when the secondaries came on, wasnt perfect, but full throttle worked
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Old 11-06-2006, 09:47 AM
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FWIW

I had some 550/720s on my car when I got it. It ran pretty rich but it ran well enough to drive everyday. Shot flames alot
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Old 11-08-2006, 07:56 AM
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Originally Posted by sen2two' post='843931' date='Nov 4 2006, 09:09 AM

http://cgi.ebay.com/ebaymotors/Bosch-Type-...1QQcmdZViewItem



thats the ebay link.



are these worth buying for my TII? i want 10psi. i have a fuel cut defender. but the motor is completely stock otherwise.



(oh and homemade crappy small exhaust, kinda)



oh...and its a 91.


First let me start by saying that changing the secondary injectors isn't going to increase boost, if that's how I interpret your statement. In fact I wouldn't recommend the 720's in a stock engine, as an overly rich fuel mixture can actually decrease performance. As there doesn't seem to be any available ecu upgrades at the present for the S5 TII, and a stand alone is costly considering the tuning involved, I would open up, upgrade the exhaust, and then you would be able to utilize the 720's, as the boost would rise. As the boost increases, additional fuel is necessary to avoid a lean condition. Although I feel the stock pump would supply enough fuel, I would upgrade to another pump for safety. An FD pump is an easy installation using the FC in tank filter. Not the best way to proceed, but it will get the job done.
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Old 11-08-2006, 08:29 AM
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Originally Posted by Turbonut' post='844524' date='Nov 8 2006, 06:56 AM

First let me start by saying that changing the secondary injectors isn't going to increase boost, if that's how I interpret your statement. As there doesn't seem to be any available ecu upgrades at the present for the S5 TII, and a stand alone is costly considering the tuning involved, I would open up, upgrade the exhaust, and then you would be able to utilize the 720's, as the boost would rise. As the boost increases, additional fuel is necessary to avoid a lean condition. Although I feel the stock pump would supply enough fuel, I would upgrade to another pump for safety. An FD pump is an easy installation using the FC in tank filter. Not the best way to proceed, but it will get the job done.




i know changing the injectors does not raise the boost. but my (manual) boost controller does. wich leads me to another problem. the boost wount raise. i already have a...well....exhaust. kinda. lol. someone cut the stock downpipe half way through and put what looks like a 2 1/2 inch exhaust until the y pipe splits. it had the NA mufflers so i just put a matching pipe single exhaust. the car was bogging. i thought it was from crappy exhaust. but it hasnt cleared up. normal driving is ok. but of hard driving it boggs.



dirty injectors?



new fuel pump, fuel filter, and regulator. would the crappy down pipe make it unable to raise boost and cause bogging also??? also i have went through 3 bottles of injector cleaner, new oil, and always run 93 on the pump.



and yes, there are plenty of ECU upgrades for the S5..
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