jamesjedi

Hi,

I have been changing my mind on this too much. I am finalising my specs for Steve Wong to make my chip. I already have the 993 injectors, as a result, I am hoping to use them. Here is what I have chosen to use so far;

- M64-01 964 long block.
- 993 plastic intake, with 964 throttle body
- 964 ECU
- 993 injectors
- engine Group B Super Cup (964.246.071.2) cams installed w/0.57 overlap
- 993 headers w/flipped flange

Any issues that some may know of using the 993 injector? I believe that the 964 is a high impedance injector. Is the 993 injector high impedance? These are the values that I have found; 993 Injectors are rated at 233 cc/min (22.17 lb/hr) @ 43.5psi or 261 cc/min (24.9lb/hr) @ 55 psi.

Thanks for any help!!!

ALEX P

No problems using 993 injectors in a 964 engine AFAIK.

I changed my injectors earlier this year due to the 964 injectors maxxing out at around 310bhp. What you don't want to do is go too big and lose the accuracy so the 993s are an obvious choice.

I ended up using E36 M3 injectors as they are cheaper, readily available and deliver slightly more than the 964s so are good up to around 350bhp.

https://rennlist.com/forums/964-foru...l#post12100423

jamesjedi

Thanks for the reply. I read your engine rebuild thread with interest. Took an hour, very good stuff.

Steve Wong says that they will work (993 injectors), but will there be any benefit? He does not believe so. As my ECU will be a stock 964, I am concerned about issues that may arise. Were there any issues that came up with your injectors? Idle issues?

I already have the 993 injectors, but don't want a headache for zero gain.

Thanks again!

-nick

If you're not crossing 300hp at the flywheel, then there doesn't appear to be any reason to upgrade. You will get more fuel squirted while cranking/starting and before the o2 sensor control kicks in after startup. You'll also get more fuel at WOT, and our 964's are already tuned pretty rich at WOT from everything that I've seen. In other words, it would probably start a bit rough, and throw some black soot at WOT and give you worse mpg. That is, unless you have the chip injector constant tuned for the difference.

ALEX P

I've had no problems whatsoever using slightly larger injectors. At idle and low revs it feels exactly as it did with the stock 964 ones.

No disrespect to Steve Wong but for me you really can't beat a proper custom map on a rolling road by someone who really knows what they are doing.

Where abouts are you based James? UK or US - If in the UK then just take it straight to Wayne Schofield and if you're in the US then someone on here may be able to direct you to a local place who knows how to tune Motronic.

Just opinion of course

jamesjedi

Even with the Wong chip, it will still need a dyno. I am in Canada.

ALEX P

So if it's got to go on the dyno for mapping anyway what is the point of the Steve Wong chip? Just to use as a base map to hopefully get it running ok?

jamesjedi

He has been used by many to create chips. I would like to think I am using his knowledge/experience. He has done a lot of cars on the Peli site.

jamesjedi

I have been thinking and reading on this all day. Hard to decide. if Steve Wong said that I will not make any gains with the 993 injectors, I am inclined to go with the 964 injectors for the sake of simplicity. After all,I am not using motec, I am using the 964 ECU.

If anyone thinks differently, let me know.

ALEX P

Haha, I see that you've already made your mind up:

http://forums.pelicanparts.com/porsc...tors-sale.html

I've stuck my two penneth in already but for me, I'd have stuck with the 993 injectors. You're set up is far from standard with the 993 plastic intakes on 964 TB, 993 heat exchangers into presumably a custom silencer along with the hotter cams. It is entirely possible that you could be right up around the max duty cycle of the stock 964 injectors and if you already own the 993 injectors and not the 964 injectors then what reason is there for not using them?

Whichever way you decide to go please keep us updated when it's all finished & best of luck with it.

jamesjedi

I will update. Thanks to all who contributed.

jamesjedi

I have just received my Steve Wong chip for the 993 injectors.

I will update. It will take a long time. I still need an oil cooler plumbed and clutch and etc...

ePa

Thread bump.

How long it will take to get update?

I am just struggling with rebuild receipt...