i run 18-19psi on 93 octane

 

what kinda setup do you have?

 

I 12.1 on my 18's at 124.
now i have T88,e6k,4 1600's with a BP.

 

Barry is that you?

 

So, if I live in Florida, I can run the same boost as my friend who has exactly the same car but lives in Colorado, right?

BTW, since none of the experts here have mentioned it so far in this thread, what does "absolute pressure" mean?

You don't say? :p

 

Evil Aviator: Don't make me "thwap" you

 

The pain would pale in comparison to that inflicted by your avatar.

Besides, I'm just asking a question.

 

lol no problem about your post, just felt you could use a random thwapping.

 

If you reread my post, I was not talking about absolute pressure. I was simply referring to the available octane. Hence why I said that it all depends on where you live. Look at Chuck in Suel... He has 89 on tap as his best gas. So, you are telling me that you would recomend running 18 psi on 89?


Mike

 

what does my avatar causing deadly seizures have to do with him talking about pressure?
lol i think ya grabbed the wrong quote

 

Your Confused Pal...
You don't need such large injectors as primaries to run high boost... The primaries are not used with boost, the secondaries are responable for that. You should use an injector that will have a good spray pattern and will optimize. This is why many people run 550/1600 or 850/1600.

 

Yeah, and he didn't get my hint about absolute pressure, either. Man, just when I thought that he was getting on the right track with the venue thing. Maybe you should thwap Red-Rx7, too.

Meanwhile, back at the ranch, old Evil STILL hasn't gotten an explanation for "absolute pressure".

 

Then I guess I'm confused, too. Do the primary injectors on your car shut off under boost or something?

 

absolute pressure is 14.5 or 14.7...i forget witch one,and its a pressure thats everywhere and on everyone.

 

It's easy guys, Absolute is Gauge + atmospheric.

Atmospheric varies from day to day (cloudy or clear) and with altitude as well, All Manifold pressure sensors on good EFI systems operate of Absolute pressure.


Most engineers talk in Absolute as well.

 

[QUOTE]Originally posted by enzo250



Your Confused Pal...
You don't need such large injectors as primaries to run high boost... The primaries are not used with boost, the secondaries are responable for that. You should use an injector that will have a good spray pattern and will optimize. This is why many people run 550/1600 or 850/1600. [/QUOTE

If he's running a Haltech in staged mode then the primaries can operate anyway he choosed too. Most of the peolpe I know running 1600's in the primaries are running them to 15 to 20 psi before the secondaries turn on. Also most of the people that I know of that is doing that are also running with 6 to 8 1600's and running on alcohol fuel at 40psi of boost.
I can't understand why would someone need such a large primary injector to run on gasolene unless they are making well over 700RWHP.Depending on A/F ratio you can make anywhere between 600 to 650+RWHP with a 720/1600 cc injector combo!

crispeed

 

Oh, now I get it. So what you are saying is that depending on where I live, my gauge pressure may be a whole lot different than someone else's, even though the absolute pressure would be the same. So this would explain why my friend who lives at 5,000 ft above sea level in Colorado can run a higher max boost (gauge pressure) than I can down at 300 ft sea level in Florida, even though our engines are exactly the same! I guess that would explain why we get about the same HP, too, even though he is running more boost (gauge pressure). Hmm, I guess it would even depend on the temperature the day we tested the engines, too.

OK, now for my next question...

I just bought a nice, new, shiny turbo and intercooler kit. I was wondering if I can run as much boost as the guy next door to me. He has exactly the same car, but he has a turbo and intercooler that is supposed to be good with efficiency and pressure drop, or something like that, as if his is better than mine, but I don't think that this has anything to do with running more boost. I think that mine is better because it came in a kit which is advertised in all the rice magazines. So, I can run just as much boost as him, right?

 

Hey Crispeed:

Alcohol is another story... I saw that he said he had an E6K so i assumed he's using staged injection... So the reason why he's using 1600cc injectors as primaries is bothering me especially in a street car. He would be better off with 550/720/850cc injectors as primaries.

 

I realy appreciate the responce guys, evan though your getting off the subject a little, someone tell me with my set up, what i should do, what size injectors i should run, and how much boost I should limit myself to, high and low. I want 450 to 480 at the wheels if its possible, and for it to be reasonably safe. I know anytime you run that much HP your never going to be 100% safe, but what would i need to run to make that HP at high boost, I know my turbo can make that HP.

 

The power you want to make is twice the amount of the stock system. The stock system flows 2800cc/min. So figure if you want to make more than twice the amount of power, you're looking at 5600cc/min (staying within stock fuel pressure and duty cycle.) If you do the math you will see why guys use 4x1600's.

Sure you can make 500rwhp small primaries and 1600cc injectors, but don't expect your duty cycle or fuel pressure to be within the stock limits (which is very safe).

To be safe I would recommend 850's in the primaries and run 1600's as secondaries.

As far as 20 psi boost on pump gas I've done it for over a year on a six port with 8.7 to 1 compression rotrs, but would not recommend it. All you need is the gas station puting 87 octane in the 93 octane tank and then it's rebuild time (personal experience).

 

Have you even seen a Greddy turbo kit?it comes with every thing mid and down pipe and a pulley kit you don't have to go out and anything . Why put in a 20b to make 500 whp? I have 4 1600s because i do not want my duty cycle to be more than 85%. my 2nd stage comes on around 16-17lbs. Turbonetics stuff sucks. anybody can make a manifold, jaytec flanges=$40 u-bends $50. if you want your car to look and run good i would think you would buy nice parts. If you have something to ask me spit it out and stop beating around the bush.

 

You tell 'em Wayne. I have 4 1600's, and I've run as high as 75%(maybe even higher at times) duty cycle on a 1-2-3-4 redline shift run topping out at 18-19 PSI, which works out to 4800 cc worth of fuel. It would take 2 850's and 2 1600's running at 98% to equal that.

 

you can argue all you want but 4 1600cc injectors is way too much for a gasoline engine making 500hp. Your forgeting you need volume not pressure. 13BAce are you still using factory fuel lines. You should be using -10 fuel line, external pump, etc...

 

"The primaries are not used with boost, the secondaries are responable for that."

Alll systems I know of use all injectors under high load. large primaries don't mean that you are making 15 psi at 2,000 rpm or anything of that nature. Big primaries are used for racing purposes. As far as spray patten If you drip gas into an airstream it will atomise. Keep in mind, Those guys running carb's don't have any sort of "sprayer". The gas gets sucked out of a hole due to the vacuum effects of the venturi and is atomised by the air. Spray pattern will affect mainly idle and low airflow situations.

Just my two cents, Share the knowledge so we can all go faster.

:1party:

 

With staged injection you run your primaries till a certain point and then your secordaries kick in... SO with small primaries you can take advantage of a good spray pattern for your idle and low airflow situations. REMEMBER WERE TALKING ABOUT STREET CARS... Why would you run such big injectors(primaries) on a street car. This is what im trying to tell you. By the time you kick in the secordaries spray pattern doesn't become a factor so you can have as big an injector you want.

As for carbs, you try to get one to run as smoothly as a fuel injected car. Especially when it's cold..