The stock FPR is fine, the only reason I'd get an AFPR is if I want to see what the fuel pressure is with a gauge (easily), or set the base fuel pressure.
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SideWinderGX;2040958 said:
Hmm....and would a 400lph in put too much fuel (for 400Hp crank) rather than a 255lph without an aftermarket AFPR??
*Actually, nevermind that question; I'm guessing the stock AFPR would regulate/set the fuel pressure.* Hehe
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you're gonna want an afpr if going with the lex/550's. the stock regulator is just a "fpr" as its not adjustable. its still rising rate though which is nice.
The stock FPR sets the base fuel pressure and isn't adjustable. Usually people get an AFPR when going with the lexus afm/550cc injectors but that's only because when you step up in power its wise to make sure everything is set correctly...there really isn't a mechanical need to get one. The fuel pressure will be the same before and after, assuming the stock one is working right.
Whatever fuel the injectors don't use will go right back into the tank via the return line, so no worry of it running richer or anything like that.
Whatever fuel the injectors don't use will go right back into the tank via the return line, so no worry of it running richer or anything like that.
550cc/min injectors are rated at 43.5psi fuel pressure. Stock FPR should be somewhere between 33-40psi at idle vacuum disconnected according to TSRM. If your stock FPR is dead set at 35psi then those same 550cc's will now flow at 493cc/min. You'd need that AFPR to set your fuel pressure to 43.5psi to maintain that 550cc/min flow to compensate for the 25% airflow increase the LEX AFM provides.
I'm no expert, but I've done some homework in the past when trying to tune my car. I even talked to some gentleman at ID injectors tech support to get further info. I still have alot to learn. http://www.witchhunter.com/injectorcalc1.php
RCEngineering has the same fuel injector calculators on their website as well.
I'm no expert, but I've done some homework in the past when trying to tune my car. I even talked to some gentleman at ID injectors tech support to get further info. I still have alot to learn. http://www.witchhunter.com/injectorcalc1.php
RCEngineering has the same fuel injector calculators on their website as well.
Suprapowaz!(2);2040992 said:
You're assuming that the stock 440cc injectors don't flow 440cc at 43.5 psi...which they do. Everything scales up 25% and the ECU is none the wiser. If you set your base fuel pressure at 43.5 psi on the stock ECU you'll run even richer than stock, which is saying something.
have you personally ran the lex/550s on a stock fuel regulator? cause really you need the afpr and a safc2 or something alone those lines or its gonna run like shit......lol
SideWinderGX;2041000 said:
Not assuming 440's don't flow what they're rated at. Just assuming most stock FPR's run at about 35-38psi which is why most people install AFPRs to bump up the fuel pressure. I never tested what my stock fuel pressure was, but I assume it was somewhere in the mid 30's. I do know when I was tuning with the MAP ECU on a stock fpr with 526cc/min I had to amp up the afm signal to get more fuel flow to run a good map. When I installed the AFPR and set the base fuel pressure to 43.5psi my map ran richer, and I had to lean out the map.
black89t;2041001 said:
Yes I have, and no, it won't. The whole point of the mod is that everything runs exactly the same as before but you have a 25% increase in airflow (and therefore power). It'll run the same as it did before the mod, because again, the ECU doesn't know the difference. What's not to get?
Suprapowaz!(2);2041012 said:
The flow chart of 550s vs 440s should look exactly the same except the 550 chart is scaled up 25% (barring the very ends of the chart where no one will run the injectors). If the ECU is looking for a 35 psi base pressure with 440s, a 35 psi base pressure on 550s will be 25% more fuel.
Is it good to eventually get an AFPR so you know where the fuel pressure is set? Yes. For this mod is it necessary? No.
SideWinderGX;2040958 said:
The aftermarket ones also have a little more dampening ability, compared to the stocker, I think. That would mean if you swapped in some monster injectors, the aftermarket AFPR would be able to keep the pressure in the rail more stable as the opening and closing of the injectors creates fluctuations.
In practice I don't think the difference in dampening really matters that much.
SideWinderGX;2041032 said:
i mean it will work but not ideal. if you like it running rich as a diesel truck then yeah. with just a stock ct26, intake, and exhaust you will get noticeable gains from the afpr and wideband leaning it to 11.5:1. stock it runs like 9:1 which kills the power. so with the lex/550's its exaggerated. i mean the afpr and afc is crude but just throwing the lex/550 on and rolling with it is even more crude like midevil lol and gonna be low on power.....i can say to make 476whp on the lex/550 you gonna need to play with fp.
I see what you're saying. No, I wouldn't get an AFPR at this point. As mentioned before my next mod would be to install a wideband. I'm sure idle and cruise areas would be fine, but I want to see what it's doing at WOT. I'm sure it would be too rich. At that point you could install an AFPR and lean out the open loop as much as you could without affecting closed loop too much. Of course you'd have to tap into and monitor Vf to see if TCCS is happy. The more you lean it out, Vf will move closer to 5v while trying to maintain stoich in closed loop. Of course that's not what you want.
You could skip the AFPR, and go straight to a piggyback. Just scale your air flow signal up or down to your liking. That way you can have TCCS control closed loop, and you just fiddle around with full throttle open loop via piggyback.
I'm not sure how other piggybacks work, but with MAPECU you have to enter in values all across the board from -20.4inHg @ 200rpm to 30psi @ 8000rpm. Of course you only tune up to your boost and rpm limit. That's a pain in the ass. I wish there was some way to to allow TCCS to take full control of closed loop, and the user to modify airflow signal only in full throttle open loop with the MAPECU. Maybe I can but don't know it just yet.
I've been running speed density and really don't like it. You have to have a few maps, and choose between those depending what kind of weather pattern you're having. People may say that's because I don't know what the hell I'm doing, and that may be true. But I do know that the stock TCCS with KVF system makes thousands of calculations/second to get that perfect air fuel ratio. It even makes corrections for weather patterns such as temperature, altitude, humidity, barometric pressure, as well as engine parameters such as timing, water temp, O2 readings, etc. Much better than any human can do. Even the top tuners in the business will load multiple maps on a standalone to compensate for all of those changes. I wish there was a way to tell the stock TCCS which injectors you're running, and to tell it to run a specific AFR at full throttle open loop. Mine's, Blitz, Techtom ecu maybe? Do those ECU's run pretty good?
You could skip the AFPR, and go straight to a piggyback. Just scale your air flow signal up or down to your liking. That way you can have TCCS control closed loop, and you just fiddle around with full throttle open loop via piggyback.
I'm not sure how other piggybacks work, but with MAPECU you have to enter in values all across the board from -20.4inHg @ 200rpm to 30psi @ 8000rpm. Of course you only tune up to your boost and rpm limit. That's a pain in the ass. I wish there was some way to to allow TCCS to take full control of closed loop, and the user to modify airflow signal only in full throttle open loop with the MAPECU. Maybe I can but don't know it just yet.
I've been running speed density and really don't like it. You have to have a few maps, and choose between those depending what kind of weather pattern you're having. People may say that's because I don't know what the hell I'm doing, and that may be true. But I do know that the stock TCCS with KVF system makes thousands of calculations/second to get that perfect air fuel ratio. It even makes corrections for weather patterns such as temperature, altitude, humidity, barometric pressure, as well as engine parameters such as timing, water temp, O2 readings, etc. Much better than any human can do. Even the top tuners in the business will load multiple maps on a standalone to compensate for all of those changes. I wish there was a way to tell the stock TCCS which injectors you're running, and to tell it to run a specific AFR at full throttle open loop. Mine's, Blitz, Techtom ecu maybe? Do those ECU's run pretty good?
black89t;2041090 said:
I found this to be true when I was running my lex/526cc's with only an AFPR. I tinkered with the fp and screw to where closed loop was spot on at 2.75v showing on the Vf readings. WOT though was piggy fat somewhere in the high 9's afr's iirc. I started to pull back fuel pressure to lean out WOT performance, but closed loop was suffering. The best I could've done at that time was 10.7 afr WOT while maintaining upper 15's afr in closed loop at a constant 5v Vf reading. I didn't like that TCCS was begging for more fuel in closed loop like that, so it was time to install my MAPECU. Then the headaches began. Just when I would get the tune down just right, it would change slightly from one day to the next. No, TCCS wasn't kicking out my tune because I always minded the Vf trim. Constantly running it at 3.5v. I preferred 3.5v because throttle response seemed more crisp there than the 2.75v range. I've tuned it to both and liked 3.5v better.
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Suprapowaz!(2);2041091 said:
Agreed on pretty much everything! After you start modding there's always one more thing you need to get to fix an issue that cropped up because of said mods, it's just a never ending snowball until you end up at a standalone with all new sensors.
I think those ECUs (Mine's and the lot) raise the rpm and boost limit and lean it out a bit in the upper rpms, but there still isn't any customization available. The ECU works good but its locked down pretty tight, unfortunately.