RedX7

Since I'm not the one who took the engine apart, I can't say for sure if that's all that failed. I just know what they told me. I know mr. rx-7tt isn't a fan of KDR, but at least they're owning up to it. I do, however, like the 850/850 idea. I'll give them a call, and see what they can do. I'm leaving on my deployment to the gulf in a week, so I won't even get to drive my car until September. I'll let you all know what happens though. Later.

donny

I wish I had the resources to build or have built, brand new 1300 injectors, not bored out. They seem like they are a very popular size.

Hamza734

That sucks about the motor. It just goes to show, never use modified injectors.

RedX7

Yep, I've learned my lesson. I'm either gonna go 4-850's, or get the the fuel rail and get some 1600's. I'm leaning towards the 1600's because I'll need them for when I go single.

Jodeny

iTrader: (3)

I disagree. If the injector is stuck closed the car will fall flat on it's face. Besides, many people run 1300's with-out ANY problems. The reason given why his motor blew makes no sense to me. Hmmm.
John

SPOautos

I agree, just like discussed on page 3 I dont think an injector totally locking up would cause your motor to blow cause there wouldnt be sufficient fuel for any combustion.

Now if there was a severe prob with spray pattern or something then that might cause a problem.

You guys need to remember when your having your injectors modified they are still your stock injectors with x amount of miles on them. Just cause a injector goes bad doesnt mean its due to it being modified, especially if you bought them used. They could have well over 100K miles on them.

STEPHEN

Hamza734

From the Marren Fuel Injection Website:
http://www.injector.com/faq.php#faq7


Does Marren Fuel Injection alter injectors to increase their static flow rates?
Absolutely not. It is sometimes possible to increase an injector’s static flow rate at a given pressure by machining or enlarging the pintle or internal passages of the injector. However, this procedure is usually not a good idea! A fuel injector cycles on and off thousands of times per minute to feed an engine the proper amount of fuel. Because of this, the electromagnetic coil and pintle of an injector are very carefully matched to one another. Modifying the pintle or other portions of the injector may cause it to flow more fuel at its limits (wide open or statically), but at lower engine speeds the injector will be extremely inconsistent. This creates drivability problems, idle fluctuations, higher emissions, rich/lean conditions, etc. We have performed extensive laboratory tests on many modified injectors and have yet to find one that performs as well as an unmodified injector of the same capacity.

SPOautos

So basically they are saying it would cause a problem at light throttle......thats not a problem with us cause you dont use your seconday inj at light throttle. It would be a prob for most cars as they run on injector per cyl but for us there is not really a "driveablity" issue with secondary injectors.

In addition your reading remarks from one vendor about another vendor. I'm sure you can go online or call RC and get all kind of glowing reviews, tests, ect, ect, ect. I wouldnt make my decision based on what thier competitors say.

Hamza734

Maybe so, but considering your engine's at stake, I prefer not to take chances. Besides, for a slightly more (~$120) you can get 1600 secondaries with all new injectors and a new FPR.

SPOautos

Yea, except then you need the injectors, resistors (if you have a PFC), harness adapters, fuel rail, fuel pressure reg, all new lines and fittings, ect. It adds up real quick.

Like I said though, I dont think them being modded are the problem, I think some peoples injectors just ran out of life. Even the 1600's only have a life span of about 100K miles. Wouldnt suprise me if people having inj prob have over 100K on thiers. Everyone needs to remember eventhough they are bored out they still have x miles on them.

STEPHEN

SPOautos

Yea, except then you need the injectors, resistors (if you have a PFC), harness adapters, fuel rail, fuel pressure reg, all new lines and fittings, ect. It adds up real quick. I spent $160 on line and fittings and thats just for lines inside the engine bay.

Like I said though, I dont think them being modded are the problem, I think some peoples injectors just ran out of life. Even the 1600's only have a life span of about 100K miles. Wouldnt suprise me if people having inj prob have over 100K on thiers. Everyone needs to remember eventhough they are bored out they still have x miles on them.

STEPHEN

Hamza734

Actually, that price WAS with everything included (well, maybe not EVERYTHING ). I still stand by my reliability comments. More then one person has lost an engine with the 1300cc/min injectors...that alone would cause me to stay away.

7racer

If that were true, how come we haven't heard of other failures with bored out injectors? Say 1200's?

Shouldn't this be happening regardless if you are modifying injectors?

SPOautos

I know THOUSANDS of people that blew engines with bone stock injectors. Maybe we should all switch over to carbs LOL

Just cause someone blew a engine and they happend to have a modified injector doesnt mean that was the reason they blew the engine.

STEPHEN

Trout2

iTrader: (5)

What do other professionals in the field such as Kinsler Fuel Injection have to say about them? I'd like to hear more opinions. Sounds to me like some engine builders are using this as a scapegoat.

Jack

Hamza734

Stephen,

90% of these faliure are due to poor tuning. With the bored-out injectors, MANY people have had problems with injectors sticking open (i.e. its directly related the injector, not a tuning mistake). I also agree the opinions of other experts would be valuable.

RedX7

KDR did try 1200's in my car after I took it back to them, and they've since removed them because of a few problems. I don't know what the problems were, but I'm glad they found them before I got it back.

Jodeny

iTrader: (3)

Once again. I would be very, very , very surprised if there was a problem with bored out injectors in Mazdas only after all of these years. It is very easy for any shop to blame failure on a mechanical part than themselves. How do they know the injectors were the cause of anything? Some people are told they were stuck wide open(over rich condition) /some were stuck closed (lean)...it doesn't make sense. There are too many factors in this car that can blow a rotary.

John
PS_ If anyone has an injector that is broke send it to me, I would like to see proof.

matty

yup!

My 3rd set finally didnt stick open.

edit: oh yeah and i was in kd's shop when the injectors were gettign stuck open..dave showed me and everything. I think there is a reliability issue with these all of a sudden. I dont think KD used the injectors as any sort of an excuse...thats not dave's style.

Jodeny

iTrader: (3)

How did he show you? It's very hard to see a pintle stuck open unless....
John

matty

had uim off....looked down inthere with flashlight. saw tons of fuel.

Jodeny

iTrader: (3)

The fuel would have flowed down the LIM. Are you saying that it actually filled it up with at least 6 ounces of gas?? That would be the only way to see tons. I guess the rotor was in the right spot to seal off the exhuast port. Is dave sure it wasn't a bad o-ring?
John

books

iTrader: (8)

a couple of comments:

would rather see some actual test results form the injector people, than some marketing blurbs

for those with failed injectors; are they being sent back to whoever bored them out for any failure analysis

rotorbrain

and a rather worthy set of comments if you ask me.

paul

rx7tt95

REDX7, not sure if you were referring to me with the "not a KD fan" but that simply isn't true. I've never had ANY dealings with them positive or negative. I've heard more positive about the shop than negative and if I lived in the area, I might consider going there (not sure on that now however). All I know is that I've run my 1300's for about 65K miles now, daily driven, daily raced, with various setups over the years. Not once have they given me a problem and I have one of the first sets of 1300's made. If we start seeing numerous shops across the country having issues with these injectors, hey, I'll be the first to swap mine out. I just think it's a little fishy. But hey, it's your money, right?