Not at all, which is why I wont even think about going over 11psi (and even at 11 its not what you would call fail safe) until I upgrade the fueling system. I believe that with a good fueling system on a stock block there would be no reason you could go even higher.

I personally think you could see much higher numbers on a stock block with a larger fuel system. I think that many tuners are using timing to extract as much tq out of the car that the fuel allows (as tuned by listening for knock). But on the other end I believe these cars still have more to give up top provided you can supply enough fuel.

Again this is just my opinion and I will be testing this fact later on. Right now I am happy with the way the car is performing.


What would really be awesome is if a company was to come out with a ECU for us. I would like to see a fuel pressure vs boost (or fuel flow vs boost) table that would take all this into account to ensure you never run lean. But its appearing that for this market that just is not going to happen. I really wish it would. I would love a ECU controlled boost controller.

500tq on the stock rods is just asking for trouble, I don't care how good your tune is or what fuel you use.

Right. but what I am saying is that at 500tq at 7000rpm your up into the 660+hp range.

All I am saying is that I believe our cars are limited on the top end because of the fueling system on them, not because of the fuel quality persay. You can only run as much air as you have fuel.

For example most of these cars sit at about 500-530hp at what? around 6500-7000 rpm? This is only ~400ft lbs. So if your saying 500 is asking for trouble, your leaving 100ft lbs on the table.

Again this is for guys looking to run the stock block for all its worth knowing full well the implications that it may cause. I like to consider myself one of those people. haha.

Well guys, if I may throw in my opinion here. A RFS is by far superior. However, I think that the stock fuel system is actually built pretty well all things considered.

I am running E85 and as we all know I require 25-30% more fuel than pump gas. I hit 533whp DJ #'s on 9.1lbs of boost and my injectors are only at 65% duty cycle. This means they still have some left in them if I needed more spray.

I do have 1000cc ID's so this does throw in a ton of differences compared to the bosch 750's. But I feel comfortable taking these to 11.5lbs. Also, my AFR's can lean a little more and Ill still have a bit more safety with ethanol.

Talk to Tony @ FI or CJM about their return fuel options. I have the Fast 500 fuel system on my car and fuel pressure issues are no more.

I need to call Tony about that fuel system.

I talked to Tony a couple weeks ago and he told me his system is basically identical to Phunks so you can't go wrong with either

See I dont know why the discrepancy vs what I am seeing then. I know on my particular car when Specialty Z was tuning it they had to stop because it was leaning out up top. Now that issue seems to have went away with a fuel pump relay, but still the loss I see in the fuel system is significant.

Are you watching your fuel pressure at all during this? I would have to go dig through my text books or google on the relationship between flow, size, and pressure but I would say just off the top that your 1000's at 65% would probably equate to somewhere around 90-100% with the 750s. I believe the relationship between injector size and flow is exponential. Again id have to do some digging to confirm.

Maybe this information is just becoming available through testing we have seen in the recent weeks. But I cant see why most of you didn't opt for the larger injectors for $150 (or so) more. You would have all the fuel you would need on stock numbers for the easiest way possible. This eliminates the need for a RFS which costs 3X more with the same simplicity as what you had already done.

If I were looking to get another 2psi out of my edged out pump gas setup, I would just sell those 750's on the market, buy 1000's, and you will have all you need. I am shooting for 11psi in the near future and from the data Iv'e collected I wouldn't need to upgrade a thing. All while consuming 30% more fuel.

I most likely will get a RFS and go for more power but I wont leave E85. The smell alone is worth it. :yum:

I upped my boost pressure just a bit more to 11.5 psi for the scamble boost setting only, but I watched the AFR closely, with how it is tune it is running 11.6 AFR at wot in 5th gear at peak boost, it only sees just over 10 in 4th and 5th gear, about 9 in 3rd. Remember its only going to hit max boost for a second before it starts to taper off. Just fyi my car runs at 11.3-11.4 AFR on wastegate pressure 7.2 psi, 11.5 almost on the nail at 10 psi and then 11.6 at 11.5 psi. Using the fuel parts supplied by sasha, bosch 750s, the 340lph pump and the wiring harness. At some point I will get my ecu reflashed so I can data log, a local shop is getting their dynojet installed now, then I will do some power pulls and see where I am at psi on the fuel pressure. Vince told me if I wanted to go e85 I would need 1k injectors, but there is only one e85 station in my area, and it is still a 30 minute drive, just not worth the hastle for me.

Based on what? I've heard this number thrown around all over the place, but have we seen any instances of bent/broken rods?

So lead the way and shoot for the moon!

My car runs a bit richer than yours but otherwise the same. Mine will run right around 10 under load actually, however knowing that your getting close to the limit of the fueling system is a bit concerning.

I also try and watch the AFR closely but you know sometimes when your spirited driving its impossible to keep as close an eye on it as you would like.


I also agree with the 1000cc injectors, unless someone else knows something I don't there should not be any issues with running larger sticks as long as the tune is calibrated accordingly.

Joepro, are you running a HKS boost controller?

Gfb gforce 2. Also I forgot the oil filter number almost ready for my first change.