You'll like the K16s. I went from K24/26 RUF turbos to K16/997GT2 Turbos w/ 3.8fpr/injectors. With proper tuning, based on data, the K16s put out slightly more power across the board. Ramp up on the K16s is a lot more progressive that the 24s.

Have you done or will you do anything to upgrade fueling?

 

Going to go ahead and do injectors. Need a few more ponies.

 

Still on stock fuel pump?

 

Yeah, do I need new ones?

 

I'm pretty sure the stock VDO fuel pump becomes marginal even at 3.8bar and around 550whp. I think I'm getting close on my set up at 1.3 bar and will need slightly more if I do a 3.8 rebuild this offseason. I'm looking at alternatives right now for a pump upgrade that would not add much heat to the fuel system especially since we are running without the fuel coolers in high heat track conditions at high power settings for extended periods of time. Different requirements than for those doing high power runs for a few seconds at a time.

 

Good info. I'll keep that in mind.

 

Injectors with oem fpr no need for bigger pumps will do 630rwhp all day long. Done it like 100 times.

 

That's like 700+ crank. That's good to know. I was always under the impression that 550whp was about the limit on 3.8fpr/injectors. I'm probably going to be rebuilding my engine this winter and doing the 3.8 conversion while at it but still running a max of 1.3 bar, road course set up. Do you think that stock fueling would still be adequate?

Marek, on the topic of fueling, do you know if a Bosch 040 flows more than the OEM VDO that is in the basket? The 040 is physically much larger than the VDO (and probably flows more?) but it is a fairly simple drop in to the factory basket. I was thinking about doing that as my OEM VDO pump is on the outs and I figured that the 040 would be a good low amperage alternative.

Thanks for chiming in...

 

THe problem is not the size of the pump but rather the lines and the fittings.

 

I understand the size of the lines and fittings is what it is, but it seems a number of people have upgraded the size of only the in tank pump leaving all else alone. Are you saying that won't offer an improvement and those that upgrade just their tank pump are wasting their time? I think Sambo said there is a company that will be offering precisely that in the near future using a Walbro.

Shouldn't the factory lines offer some extra flow capability? Not talking about double, but a 25-30% improvement maybe with a better pump. After all, the GT2 pumps maybe 10-15% more volume throught the stock lines by the nature of the lack of its jet pumps. You seem to favor / sell the extra 044 in line pump if I recall. Doesn't that use stock lines ? Unless I'm mistaken, even those people that upgrade the lines going to the motor don't upgrade the OEM return lines so that would still be your bottle neck ultimately, no? Wouldn't you have to upgrade all the lines to actually increase flow through the system?

Thx