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Discussion Starter · #1 ·
90 daytona es 2.5 turbo I
rebuilt engine with 2500 miles
giant front mount intercooler
hybrid T3/T4
stock fuel system (adjustable fuel pressure regulator sitting in box still)
stock exhaust system
grainger set to 10psi
no charge air temp sensor
stage 3 computer (fwdperformance)

i'd like to add more fuel to reduce my AFR from 11.4 to say 10.5 at 10 psi. how exactly do I go about doing this?

I would imagine i just install the AFPR and turn it up a little bit above stock pressure.

but then wouldnt the car run rich at idle, part throttle, etc..?

or does the closed loop O2 feedback have enough span to adjust the mixture to be correct even when fuel pressure goes up? (when not at WOT)

I also have +40 injectors sitting in a box, but the stage 3 computer isnt compatible with them so im waiting until I get the stage 5.
 

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Well, the stage 3 computer isn't programmed to run the +40's at the stock fule pressure...not necisarily that you can't run them period.

Yuo ask how to add more fuel...the best way that you have at your immediate disposal is to put the +40's in and install the AFPR. Then turn the pressure DOWN until you achieve your desired A/F ratio.

Personally I think you are fine at what the car is doing now.

If you go the route I suggest you will be ready for the stage 5 when you get it, plus you take strain off of the fuel pump allowing you a safety margin.

I HIGHLY suggest getting the 255 pump when you get the stage 5. You *may* encounter that the 255 pumps TOO much fuel and you might have to upgrade the return line to the tank. I had to do it, but two of my other friends did not...there's no real telling until you do it.
 

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Discussion Starter · #3 ·
thanks for your response. this begs a question:

how much modification to the injectors and/or fuel pressure can the computer compensate for WHILE IN CLOSED LOOP. NOTE: presumably the computer cannot "compensate" for injector and/or fuel pressure changes AT ALL while at WOT because it is then "open loop" and ignoring the O2 sensor.

THAT BEING SAID/ASKED:

let me think out loud here about what you said:

(lots of colons i know)

so lets say i put +40's and the AFPR in and adjust the fuel pressure according to the +40 flow rate to EXACTLY mimic stock injectors

NOW, when then computer sends a certain pulsewidth to the injectors and expects a certain amount of fuel to be sprayed, will it get it what it expects? yes. because the bigger hole in the injector flows the same amount of fuel as stock at the lower pressure when you pulse it for the same amount of time.

so everything seems great. lets all just throw in +40's and an AFPR and give the fuel pump a break.

PROBLEM: turning down the fuel pressure too low probably affects the spray pattern of the injector (got this from thedodgegarage.com). i dont know if in my particular situation i would have to turn the pressure down so low that this would happen.

QUESTION: if i can get my stage 3 (or theoretically a stock computer even) to work with +40's, then why do I need a "special" computer that is "calibrated" for +40's?

ANSWER: (my guess) if you wanted to add ALOT more fuel, and you just turned up the pressure on +40's with your stock computer so they flowed more than stock injectors, the computer would no longer get what it expected out of the injectors and would run RICH whenever it was in closed-loop.

a "SPECIAL" computer knows you are planning to do this so it has shorter pulsewidths in its big closed-loop lookup tables and elsewhere so that it doesnt run rich

hows all this sound?
 

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I will say this: Gus ran something like 27# of static fuel pressure in his cars. He ran +40's, 255 pump, an AFPR, and a RRR(for his REALLY high boost). I don't beleive he ever ran in to a problem with the spray pattern. Could it happen? Sure. Is it something you need to worry about with brand new injectors and an up-to-snuff fuel system? I don't honestly think so.

Your thinking on the adjusted pressure working with the +40's and the AFPR is somewhat correct. During normal driving the comuter will have enough leway to adjust for optimal A/F by adjusting the pulse width. Under WOT the computer is set to open the injectors a certain amount of time(this is usually on the VERY safe side, hence the reason this works) and for that given time the +40's will STILL outflow the stock injectors even at a reduced pressure. The other thing you have to remember is that the pressure in the rail is also going up in direct proportion to the boost. So as the boost rises, the fuel pressure does the same..the more pressure, the more the injectors will flow(there are losses due to the resistance of the pressure in the intake, but they can be neglected for our purposes).

You thoughts on how a custom calibration works with the larger injectors is dead on. One other thing to consider, especially with the stage 5, is that it is programmed to work with a 3-bar MAP. That means it is capable of reading higher boost levels and can be run at those levels without any sort of "tricking". It is also calibrated for those levels of boost and therefor is *safer* to run up there. You still run the risk of blowing an engine due to other stupid stuff, but the cal should not really be the cause. There are also timing table differences to help with spool-up, part throttle response, and off-boost performance.

A custom cal is probably one of THE best ways of gaining better performance from a computer controlled car becuase of all of this.
 

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Discussion Starter · #6 ·
reaper1: thanks for the great info!

here is the reason I am even worried to begin with, and I think I need to re-examine this because it may be FALSE

I have an OTC MOINTOR 2000 and under full boost it says there its lots of knock retard, and therefore I assume I am having DETONATION. The knock retard bounces around and isnt the same on each cylinder, so it doesnt seem to be some kind of automatic look-up table kind of thing, it seems to be a response to the knock sensor.

this worries me greatly.

the plugs all look the same, very light tan.

but maybe, somehow, this all means nothing and im not getting any detonation?

SO, I think the IMPORTANT QUESTION, IS:

without the OTC monitor 2000, how would I go about determining if I had detonation or not?

i posted asking what plugs would look like with detonation but nobody replied.

so how the heck am i supposed to do it?
 

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without the OTC monitor 2000, how would I go about determining if I had detonation or not?
Some Cals flash the check engine light, but this is the same as reading from the scanner. You HAVE detonation as being reported by your sensor(but it could be false), so either way you have to make the computer see 0 knock because its pulling timing. If its false then using teflon tape on the sensor threads will buffer it a little. BUT YOU BETTER BE 100% CERTAIN IT'S PICKING UP FALSE KNOCK!!!

So like I already told you(couple times) the easiest way for you to see if its real or false is to add some better gas and watch again.

If your like me and dont have a knock sensor you can make a device similar to this and listen for it.
www.neons.org :: View topic - $29 "det can" how-to - *56K no*
 

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Man...that article is cool! I might have to give it a shot myself! LOL
You can do the same thing using a hearing aid type microphone from radioshack so you dont have to route the thick hose into the passenger compartment.

Basically just use normal headphones that plug into the device, take the device apart and extract the mic's and glue them to a clamp(which goes on a bolt near the knocksensor, or possibly the knock sensor itself, prob have to extend the wires for the mic(s)

looks like this
 

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The 3 bar maps scale down the +40s doe that they open a lot less during normal operation. Then they can open farther into high boost. Anything below 11 AF and your killing power and not helping things, I always aim for 12:1 with a turbo. 13:1 is best for power but risky with a turbo, all my V8 Mopars I aim for 13.2:1.

Hooked up right a good cal will pull timing and boost if the engine trys to detonate. Once you get higher in boost the engine makes a lot of noise, without detonating the 2 bar cals pull timing. Other than fuel scale and bar scale the knock sensor is turned down to allow more noise, noise caused by power. Just get a AFPR, stage 5 cal, MSD 3 bar map and +40s and aim for 12:1 AF. Running super rich will wash the oil off the cylinder walls, hurting compression and contaminating your oil with fuel. So running super rich like that you can shread your engine instead of melt it.

Drowning your engine with fuel and running low trap speeds like Gus did and waring a beer bong on your head and trying to find knock is the wrong direction folks lol. Not to mention either that a high boost 2.2 without knock is going to make you deaf if the thing works right. I know a good 3 bar setup is expensive, but it is cheaper than over doing a 2 bar. The reason is the engine will just last longer and give you the power you want. I took the engine out of my GLHS 8 times trying to find the cheapest way through, cost a lot more in the end..... 02$
 

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Your tan plugs say that the mixture is ok. To answer your question about reading the plugs for detonation, the plugs will have little black specs on the porcelin if it is indeed detonating. There are many factors that can contribute to detonation. The number one contributor is heat! You did all this wonderfull stuff to make more horsepower which also makes more heat. Did you beef up your cooling system? Do you have a 180 t-stat? Is your radiator flowing up to par and is it still the same stock radiator rated for 185hp? I would look at these areas and the type of fuel you are running first before I adjusted anthing with your a/f ratio.
 

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Discussion Starter · #14 ·
OKAY, to get everyone up to date:

wideband O2 has been relocated downstream (more than a foot from beginning of downpipe)

+40's have been installed

AFPR has been installed

after i installed the +40's and AFPR i began the trial and error process of adjusting the fuel pressure so this setup would work with my non +40 computer

heres how:

i set boost to about 4 psi

at WOT AFR was 12.4!

turned up fuel pressure

repeated

(etc..etc..etc..)

to sum it up I eventually had boost turned up to 10 psi and the AFR was about 10.3 at WOT

EVEN SO

OTC 2000 reports double-digit (I saw 10 degrees) of knock retard on multiple cylinders

SO

I suppose the next step is to get the 104 octane booster and see if it fixes it.

HOW EXACTLY DO I DO THAT?

pour in the bottle, then go for a drive, and see if there is zero knock retard?

what if there is? what if there isnt?

what do I do then?

i dont want to get a water/alcohol injection setup. i have a GIANT front mount intercooler and I want to do this without that.

i dont have access to better gas, im in san diego and the best they got round here is 91.

i dont want to pour in octane booster to run 25 psi (eventually)

SO, what are my options?

MORE IMPORTANT INFO!

I **DONT** have a 180F thermostat. I have a stock thermostat, stock radiator, and probably a very high coolant/water ratio (long story). I will change the thermostat and make the coolant mostly water ASAP.

Do I really need a new radiator? I have the wide one for the 2.5 T1. And its NEW, less than 2500 miles.

****REALIZATION****

I asked you all how to tell if your engine was detonating WITHOUT an OTC 2000. You gave me two ways:

Hook up the hearing aid/can thing and listen for it

OR

Check the plugs for black specks

I may try the hearing aid thing. But at the moment:

MY PLUGS HAVE NO BLACK SPECKS

So If I didnt have the [email protected](#*@ing OTC 2000 I wouldnt think I had any detonation!

Like you are all saying, the engine gets LOUD at high boost so maybe thats all this is?

ALSO: my plans DEFINITELY include the stage 5 computer and 3 bar map. in fact i already have the 3 bar sensor. but I want to get all this settled before I move up to any higher boost.
 

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at 4psi 12.4 A/F is acceptable, you should prob try that fuel pressure and see what the A/F is like with 10psi. With out a standalone to adjust fuel at different points, its a compromise so having good drivability and safe A/F's at the intended PSI @WOT that you run(meaning if you set it for 10psi you may have to ajdust it again for running 15psi and so on)

Another thing to consider is that the knock sensor DOES have a torque spec!(so check this 1st!)

I would get a couple bottles of octane booster and add it to a 1/2 tank of 93 octane gas, poor it in and drive around a little so it mixes in good(maybe do some turns and braking to slosh it around). If it still reads knock and you have torqued the knock sensor properly, then it is false knock. So you need to take the knock sensor off and put some teflon tape on the threads to desensatise it, or try another knock sensor, or move it to a different location. If the knock goes away then look into the timing (cam and ignition) to make sure it is set properly.

Another question have you tried lessening the timing a couple degrees to see if the knock goes away?
 

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Discussion Starter · #16 ·
yes i realized after a bit that 12.4 at 4psi was okay..but at first it was alarming. i eventually got the fuel pressure worked out, although some will think low 10's is too rich at 10psi.


i am fairly positive that I torqued the knock sensor correctly since i bought a socket specifically for it and i always look everything up in the factory service manual, but i'll recheck it. im also fairly positive its a new sensor i got from fwdperformance.

remember ive only got 91 octane here. does that seem hopeless?

i know the cam timing and ignition timing are to stock spec unless a tooth was skipped, but i'll check

i have NOT tried adjusting the timing. what is the idea behind this? what are the drawbacks?
 

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Discussion Starter · #17 ·
OKAY I ADDED THE OCTANE BOOSTER :)

tank was 3/4 full
added +104 MAXIMUM (thats the brand name), it says it can treat up to 25 gallons, and it can increase octane up to 6 numbers. So my 91 octane pump gas can get boosted to 97.

After pouring in the bottle, I filled the tank up with 91.

Drove about 10 miles.

Boost set to about 10 psi.

At WOT in various gears and rpms on the freeway, I still saw up to 8 degrees of knock on multiple cylinders, and even 14 on cylinder #4.

AFR was in the low to mid 10's.

Its like nothing has changed.

EGT's seemed to stay under 1500F, (highest I saw was about 1450F?), but its hard to do this while driving, plus my EGT gauge has a very slow response rate so I'd have to keep it at WOT for about 10 seconds for it to fully settle, which is hard in traffic. :)

SO.

What does this all mean? No knock? Should I put together the hearing aid thing?

How do I know that 97 octane is enough to guarantee no detonation? Is that the logic to this test?

Heres the problem folks. My goal is 25 psi. The only upgrades left are an exhaust cutout, 3 bar map, stage 5 computer, and probably the fuel pump. THATS IT. I could have all those parts installed NEXT WEEK. There is nothing keeping me from going to 25 psi except not knowing if I am detonating or not. THIS IS IT. Except for the hearing aid thing, there arent any other tools I can really get to help me figure this out. So either I know its detonating by now or not.
 

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Octane booster is kind of missleading. When it says it will raise the octane by a certain number of points, they are not talking about whole numbers! They are talking 10ths of a whole number(this is considered a point). So...you took 91 and raised it to a maximum of 91.8...possibly 92. They don't tell you that, and it's not common knowledge for the average Joe. It's not to say the stuff doesn't work, and it's not to say it's a bad product, but it IS the truth.

I know you said you don't want to run water/meth injection, but I think your case is the PERFECT situation where it will be useful! Especially if you use meth in the mix!

Knowing you don't want to run that though, I would try the colder plug thing. That is inexpensive(comparitivley) and easily changed. If it works...GREAT. If not, you're not out a lot of money or time.
 

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Discussion Starter · #20 ·
The +104 stuff I bought says it boosts up to 60 "points" which it explains is 6 whole "numbers". Not that that really matters though anyways since who knows is 97 is enough to do anything. So is the bottom line here this test was meaningless?

Okay I'll go find race gas sheesh. :)
 
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