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Maxed out 550's?

Ok, I got a set of RC550cc right now, i posted an article earlier about me dynoing my car. and getting HP:336 at 21-22 psi at the wheels, up to 7500rpms but then past that i just get crazy knock like 12-19 counts and my timing retards. Everything above 4k is +50% on the AFC. it goes fine before 7k but as soon as it hits it i get knock, That was on 110leaded, now on 91 oct. anything past 15psi and i get knock like 9-13 counts. I realize that +50% is sh*t load of fuel. but if i go lower i get knock, I got the 255 Fuel pump, 2G MAS, 43psi base idle with the "B&M" FPR.
What trips me out is that anything past 15 psi, i get knock. I keep 15psi up to 7+k without any knock, but not any higher psi.
ThanksJohn
795/1000[This message has been edited by khadiyev (edited 08-19-2002).]
 

anybody?
I guess all we talk about is white face guages, bodykits and shift boots.
 

What turbo are you running?
Are you sure your base timing is close (5-8 BTDC)? And I don't mean according to the datalogger. I mean with the connector on the firewall grounded, and using a timing light.
I have a similar setup, but had NO knock on 100 octane fuel at 20psi. Of course, I don't take mine to 7K very often though.What cams are you running that pull to 7500 rpm?
Have the injectors been cleaned lately?
 

it's a 20G, 06 housing,
I checked the timing with the light it's exactly at 5deg btdc, with the plug grounded,
2 week old knock sensor, got the HK$ 264s cams, cleaned my injectors 2 weeks ago. Knock sensor screwed in to about 12-14lbs. John
 

Are you sure you're using the correct ECU, one thats intended for a 5-speed Turbo?
How about fuel restrictions, like a clogged filter, kinked hoses, etc?
I just can't see how you'd have ANY knock at only 21 psi with 110 octane!
Jeff O.
#1886/2000
 

Nate

Well-known member
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Feb 23, 2001
Messages
944
Location
Worcester, Pa
Too much fuel can make the car knock, bad knock sensor can cause the car to knock. Change the fuel filter lately? Change the sock on the bottom of the pump lately?
 

number3

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Joined
Jun 26, 2001
Messages
7,623
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BTW you really don't need to "run" past 7K. The peak power with stock intake manifold is 6500 ish.
 

Even with that big turbo you got? hehehe
What do you shift at Harry? When does your t4 bb come on? rpm wise.
Thanks,
Rob
 

The ECU is a Stage 3 from TMO, 3k on the fuel filter, cleaned the sock on the the bottom of the fuel filter about 4k ago. I have my pocketlogger log, also the dyno sheets, i don't know if i can upload them here or make a link, i don't have a webpage to store it on. But with the wide band 02, everything before 5k shows really rich,9:1, 10:1 area, but as soon as it reaches 12:1, 12.5:1 it gives me knock,and that's the leanes (ratio) though out th whole dyno chart. Oh yeah and the Intake manifold has been "extude honed" I bring it up that high so my boost stays up, i got petty bad lag on this turbo with 2.5inch exhoust full boost only by 4200-4500.
John
 

Dan D

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Joined
Feb 27, 2001
Messages
1,161
Location
Brownsburg, IN
What are your injector duty cycles? List them in ~1000 rpm steps for us. My thinking is that maybe your maxing really bad by jacking up the safc so much. Your spray pattern has probably gone all to hell with that much fuel added and the injectors are forced into 100% dty cycle earlier the rpm band. If at 100% duty in your midrange, your spray pattern will be gone and may be creating hotspots inside the cylinder which rear there ugly head as pre-ignition/knock as pressure builds and rpms rise and timing advances.Just a guess, of course if your dty cycles look fine then nevermind.
 

number3

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Joined
Jun 26, 2001
Messages
7,623
Location
KoP, PA
quote:Originally posted by Team Ducktape:
Even with that big turbo you got? hehehe
What do you shift at Harry? When does your t4 bb come on? rpm wise.
Thanks,
Rob
The turbo is a sore subject right now.It hit about 3600. Yeah the intake seems to bild power at 6500. I haven't proven this with tons of dyno runs of many cars but so far that looks to be true.
 

1st 23-26psi
6968rpm--26 counts of knock--11 deg,--0.78 O2,--17.436mS, (boost just goes up on me so i had to keep it part thorttle on ALL the runs, my TPS volts were average of 2.5, that's why the INJ mS is so low at that rpm. 2nd run.18-22psi
6k--24deg--0knock--0.76--22.821mS
65k-18deg--20knock-0.73--24.103mS3rd run(21 psi blew IC pipe, no beed
smile.gif
0-6343rpm--0 knock 25deg of adv at 6300r's02-- 5k -- .81 19deg inj-20.769mS
02-- 5.5k- .80 22deg inj-21.026mS
the last run i had no knock the whole time untill i blew IC pipe at 6300rpm
 

Nate

Well-known member
Joined
Feb 23, 2001
Messages
944
Location
Worcester, Pa
So just to be sure, you have changed the fuel filters to ensure that the leaning out isn't a delivery problem, right? That is pretty high ms numbers for the stock ECU, I don't usually see them go over 17ms anymore, no matter how much boost I'm running. If the pump isn't rewired, rewire it and hopefully gain a little additional pressure and some delivery, but I'd try to add fuel however you can at the rpm range where you're running so lean and getting knock.
 

pump is rewired!
and the AFC is MAXED OUT from 4k on it's +50%
he-he
smile.gif
that's what trips me out. that's why i plannin on getting some 660, next week, and wanted to know if i need them.John
 

quote:Originally posted by khadiyev:
Ok, I got a set of RC550cc right now, i posted an article earlier about me dynoing my car. and getting HP:336 at 21-22 psi at the wheels, up to 7500rpms but then past that i just get crazy knock like 12-19 counts and my timing retards. Everything above 4k is +50% on the AFC. it goes fine before 7k but as soon as it hits it i get knock, That was on 110leaded, now on 91 oct. anything past 15psi and i get knock like 9-13 counts. I realize that +50% is sh*t load of fuel. but if i go lower i get knock, I got the 255 Fuel pump, 2G MAS, 43psi base idle with the "B&M" FPR.
What trips me out is that anything past 15 psi, i get knock. I keep 15psi up to 7+k without any knock, but not any higher psi.
ThanksJohn
795/1000[This message has been edited by khadiyev (edited 08-19-2002).]
 

Why do you have your fuel pressure so high? My car didnt run well until I lowered the pressure with a AFPR. And then I still had to lean the AFC to make power. I'm using the 550's, big 16g and 2nd Gen MAS. Are you sure you have to run +50%? When do your EGT's get too hot?
 

My EGT guage is not working right now, my needle keeps bouncing around,when roll the window up,or turn on a turn signal.
Keydiver! that's a VERY good guess.
I'll try to fix my boost creep and turn down the fuel pressure. I'll see what happens then.Thank a lot for everybody's help!John
 
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