2fcknfst

As I understand it, the 996tt x50 has 44lb injectors. As my x50 is 15 years old, and I am taking the engine out during the off season, I was thinking about adding a 5 bar fpr as well as a set of these Bosch 0280158117 550cc/52lb/hr injectors; not that I want to make gobs of power, however, I do have a power target of 550/575hp. I am looking at this as a predictive maintenance measure as I will also swap out all the hoses, alternator, water pump, etc.

On other cars I have built in the past, a modest increase in injector volume and adjustable fpr, have done well in meeting the increased fuel demand, along with retaining drive-ability. I was able to trim them (I will do the same thing with the Cobb tuner) to be sure there was always enough fuel, especially under heavy-ish loading.

These Bosch units are quoted as direct replacement, and I am wondering if anyone has had experience with this type of combination.

Cheers,

993GT

keep the stock FPR and do injectors only... some tuners have preferences as to what injectors/size they want installed, worth asking your tuner first

2fcknfst

I will be talking with Sam about tuning the Cobb. So, the stock FPR will provide enough consistent pressure to support a (approx) 25% bigger injector?

32krazy!

leave the stock fpr in the rail and add a set of 1300 cc inj and have your tuner scale the inj. car will run like stock on fuel and handle up to 750 hp with no issues.

SamboTT@ByDesign

We should definitely have a chat before you order parts. make a solid plan and path. 1300's are the best and will cover you for good hp as well as factory drivability.

2fcknfst

Yes, I intend to - I am not ordering anything yet, I am learning...

A 1300cc/123lb injector is huge - I do not even have injectors that big on my diesels!!! How is it possible to ever not run rich? Especially under load... wow, that is more than double of what I was thinking would be a good, reliable update.

SamboTT@ByDesign

32krazy!

you can get 1000 cc inj from fid if thats what you want. injector dynamics 1300 cc in j are simply some of the best inj made. not cheap but worth every penny perfect flow match and they seem to pull more power than any other inj. prodigy made 1500 rwhp on id 1700 cc inj on race fuel. 1300 will idle like stock. if theres any oissue it will be the tuners fault not the inj. tony stands behind every inj made. this gives you plenty of headroom for the motor and you will run out of pump before inj. pump is 10x easier to swap than inj with the motor in the car.

2fcknfst

I'm just going for up to 575hp, but those numbers are impressive.

32krazy!

famous last words!!

nbressette

FWIW, I run the Siemens 60lb and they work perfectly for those numbers. If you can find a good set on ebay you can get them cleaned / balanced and save some $$ for other mods.

2fcknfst

I know, I know - I bought an F10M5CP a couple of years ago and swore, up and down, that I wouldn't do anything to it...

710hp and 660ft/lbs later, I have proven myself a liar.

2fcknfst

You know, I was thinking that with the 52lb Bosch units - PN 0280158117 - new updated design, higher resistance under $300USD for a set, direct drop in, and approximately 25% more fuel flow, so that is how a I am leaning. 1300cc monster injectors sound neat, but it is important for an injector to cycle or it gets bunged up. Plus I am pretty solid on my power gains to only go to 575hp.

2fcknfst

The Siemens website is a whole bunch easier to figure out than the Bosch one - with your 60lb units, are they short, mid or long?

Cheers,

nbressette

https://www.ebay.com/itm/Porsche-996...EAAOxyZw5RbhlY

Same as those, long enough that my fuel rails needed to have a spacer added. The advantage is they use the factory plug so no adapter or modification to the turbo support bracket is required.

edit: just realized thats Sam's auction lol