I was jus wondering how much boost the stock fuel system can handle all by itself? If anyone knows this I would greatly appreciate it so I can move forward with my turbo project. In my setup right now I have a walbro 255 pump, Malapassi rrfpr and some unknown size injectors owned.gif But Im only going for 8-10psi of boost and was wondering if the walbro and the rrfpr would be over kill. I dont really plan on going any higher than that either.

May be a lil off topic but still pertaining to boost, but Ive doing my research and have read two different stories bout retarding ignition timing. So is it needed for 8-10psi of boost or is it not? Boost heads, your wisdom is needed. Some of my Honda buddies say for every pound of boost I add I need to retard igntion timing by .5 degrees. Sound right?

 

I'm no pro but I think I can help answer these.

For fueling, yes, the 255 is overkill. You can get away with a 190lph walbro, and no fpr for your boost goals.

For the timing, I'm not 100% sure and someone will have to chime in on this, but I believe that you shouldn't have to retard ignition timing for your boost levels as long as you have a good tune and are running premium fuel. Another way around this would be to lower the compression.

What are you using for fuel tuning?

 

A few things:

First, all fuel pumps flow less with higher fuel pressure. A general rule: for every 50% increase in pressure, expect your pump to flow 50% less. That's not really applicable to lots of aftermarket pumps, but your stocker will very certainly dwindle in output capacity as you increase pressure. So, the best thing to do with your RRFPR? Sell it.

Second, if you bought those injectors second hand, send them to RC Engineering. For a nominal fee, they'll clean and flowbench each one. That way you will A: know they don't drip, leak, or otherwise are effed up in a way that will kill your motor when boosting, and B: you'll know exactly how big they are.

Third, ignition timing depends on LOTS of things. Intake air temperature is one, which can be directly impacted by the efficiency of your turbo, whether you're intercooling or not, where the intake for your turbo is placed, and how designed your intake plumbing is. Another is fueling -- both quantity, and quality. You can put off a bit of ignition timing by overfueling to a certain point; you can also put off a bit of ignition timing by using 93 octane, although many areas on the country only sell 91. Use colder plugs, gap them smaller, and stay away from more than about 15 seconds of hard acceleration at a time (which, if you're turbocharged, should be ALL that you'd need to do anyway.)

Finally, get a remote fuel electric pressure gauge -- even if you have an aftermarket pump. If you EVER see your fuel pressure drop below that at which you set it, then you immediately know you have a problem and can get off the gas before you turn your motor into a shrapnel weapon.

 

Thanks for the answers. That actually helped out alot. As for tuning, I havent decided exactly what I wanna do quite yet cuz of money issues. Ive thought bout the smt-6 because everyone has great results with it. Ive also thought bout using an AEM fi/c too. Alot of this depending on my finances in what not.

Ive read of some members here who have ran like 3-4psi of boost bone stock with no tuning what so ever and have decent results. I have thought bout this for awhile too but not real sure if I wanna take that chance of messing something up. Thats slightly part of the reason why I started this thread. I mean I planned on doing that until I could get a decent fuel tuner. I would get an safc2 but I have heard they are crap too.

So most of my turbo grocery list is complete cept for a wideband and a tuner. Im goin with an AEM UEGO wideband as of now. Any suggestions to a cheap fuel tuner thats actually reliable? Im guessing FMU's are crap too? Cuz hamhead ran like 11psi o'boost stock like that and he didnt have problems at all. Jus trying to clear up some confusion on my end so I can go boost soon. Who know this could cause so much frustration?

 

well as far as tuning goes and seeing your funds are i would go with AEM FIC/UEGO combo...has great results so far and you can make your on plug and play harness with the FIC wired between male and female connectors to the ecu...

SMT 6 will require Turbo box (force ecu into open loop) and Dual Rail kit from AtheilerHP...you achieve good results with the ability to maintain stock fuel maps when not on Boost, but the dual rail kit is expensive but worth it IMO, gave us tiburon owners reliable method of tuning w/o going full stanalone...

another would be MS Standalone but 2 people have them installed, 1 is trying to sell his...so the jury is still out on that one IMO...but an option

If you going to do it, do it right the first time...learn from past members threads fing02.gif

 

I recommend the FIC/UEGO combo also. If you are going to get an FIC at some point, just get it already and don't spend money on any FMU, RRFPR, or whatever.. the FIC will be all you need

 

Another good option from Perfect Power is the TF-10. I run it on my Turbo'd Beta2 Tiburon and LOVE IT! Plus you won't have to choose between running subinjectors or Timing. The TF10 can do both as well as one of the two Analog input/outputs can be used to modify your TPS signal so no need for a 'Turbo Box'. smile.gif

The TF10 has a MUCH greater tuning resolution compared to the SMT6 so I bet with 440cc primary injectors you could reach your goal of 10-12psi with no problem.

 

Ok I havent update this for awhile now. But my turbo project is slowly come to a finish now! Yay. But Im gonna run a TO4E t3/t4 turbo and roughly 10-12psi. Now how much fuel can the stock fuel pump supply if Im running 440cc injectors? Will it suffice or should I use the 190 dsm fuel pump? I have a walbro 255 I could use, but I dont wanna replace the stock fpr like ive been told you will have to do if you use the 255. This sound right to anyone, help plz?

 

you want to run 10-12 on stock fpr and stock pump?
get yourself a fpr and use the 255 walbro, damn

 

Now I didnt say I wanted to run 10-12psi on the stock fuel pump. I was jus asking if you could run it. Outta curiousity. I mean cuz I have the 255 but have heard that on lots of cars that they start to suck air close to round like a half or quarter of tank of gas. Now when you're poor like me, your gas guage is always under that! But unless thats not a problem with the tibby then I may jus go that route radu. Or should I use the 190 dsm one and call it a day with the stock fpr? Ive heard with the 190 you're able to retain the stock fpr. Ive read that alot of ppl use the aeromotive fpr or something like that, is that a direct bolt on or does it require modding? Thanks.