Trimming back fuel on SAFC/DTEC, cause PCM to boost more? - SRT Forums

westrock · 04-01-2006, 01:37 AM

I'm getting a 50 Trim with DTEC and 650cc.

I remember back when the SAFC trick first surfaced in the Honda world the reason it worked so good was because by matching the injectors to the turbo you could trim back enough of the MAP signal that the ECU (PCM) never saw a positive source, because the MAP signal was so trimmed back that it stayed in vacuum.

For now I just plan on using the PCM and only boosting 17-19 PSI. So my question is if I trim back the MAP signal to use the 650cc injectors, and say the PCM has a target of 19 PSI, but the PCM only sees the MAP equivalent of 17 PSI, will it let the turbo go up to 21 PSI to get the MAP signal at 19?

Vector · 04-01-2006, 01:56 AM

only if your on the black line and stock turbo

TNT · 04-01-2006, 02:29 AM

This is what I was wondering. Can I run a stage 2 with a ported & clipped turbo/manifold and use a detc to adjust the map and set it for about 22psi on #3 and be able to hold 20psi to 6000rpm due to the turbo mods. It think it would still run rich so a big TB and a ported intake should help. I am also planning a return line fuel system to finish fine tuning it. I have a mopar cai and a borla catback(which is getting a 3" down pipe) and some other mods. I was hoping to get about 310hp or so like this if not a little more

. Some headwork and cams will come later. I like the power curve of my car now I just want to hold more boost to 6000rpm and keep a useable flat high torque curve. As a driver/toy this is about the max power that is usable IMO on stock ACR sized tires. I'll probably get about 12k to a set of 4 how I drive.

possible or not?

westrock · 04-01-2006, 03:22 AM

Quote: Originally Posted by Vector

only if your on the black line and stock turbo

Are you saying the PCM <solenoid> cannot control the Turbnetics Evolution wastegate supplied in the AGP kit? I would assume that if you put a lower spring rate in that the PCM would still be able to control just like an internal wastegate.

dansrt4 · 04-01-2006, 03:36 AM

Quote: Originally Posted by westrock

Are you saying the PCM <solenoid> cannot control the Turbnetics Evolution wastegate supplied in the AGP kit? I would assume that if you put a lower spring rate in that the PCM would still be able to control just like an internal wastegate.

Just curious but if your running big turbo why would you waste your time running stock vac lines. Just curious not trying to be a dick

westrock · 04-01-2006, 06:13 AM

Because I don't want to spend money for a fancy boost controller and or map clamp at the moment, but also because I don't want the PCM to get unhappy an throw CEL's. Besides a 50 Trim at 19-20 PSI is right around the power levels I am looking for right now, so it works out.

I guess depending on what springs come with the AGP kit I could just directly run the wastegate off the turbo.

I know most poeple wouldn't take that route, but I don't see why I wouldn't be happy with it. Unless of course the stock solenoid is too crappy and will fluctuate alot. But the turbo spools slower, so it may be more controllable compared to the quick stocker that spikes real bad.

getnpsi · 04-01-2006, 06:59 AM

most people i see have nothing connected at all. I have a 1 bar spring on the external wg and then have a "fancy" boost controller from there. Old numbers i put down running off the wg only was 265. no cels no slowness at all that route.

mario03srt · 04-01-2006, 11:53 AM

Quote: Originally Posted by TNT

This is what I was wondering. Can I run a stage 2 with a ported & clipped turbo/manifold and use a detc to adjust the map and set it for about 22psi on #3 and be able to hold 20psi to 6000rpm due to the turbo mods. It think it would still run rich so a big TB and a ported intake should help. I am also planning a return line fuel system to finish fine tuning it. I have a mopar cai and a borla catback(which is getting a 3" down pipe) and some other mods. I was hoping to get about 310hp or so like this if not a little more

. Some headwork and cams will come later. I like the power curve of my car now I just want to hold more boost to 6000rpm and keep a useable flat high torque curve. As a driver/toy this is about the max power that is usable IMO on stock ACR sized tires. I'll probably get about 12k to a set of 4 how I drive.

possible or not?

You need to talk the Guy that made the frankenstein stock turbo. I don't see it holding 20 psi to redline @ 6000 myself.

Good Luck.

Marion

westrock · 05-26-2006, 11:38 PM

I just wanted to comment some after installing everything.

I am using the DTEC and manual boost controller. I have the turbo set to 17.5 PSI right now (using the Stage 1 MAP voltages seen on the DTEC). The DTEC "trims" the signal by a certain percentage and outputs the new signal to the PCM. So when you boost 17 PSI thats 4.67 volts. The DTEC trims 20% off that so its 4.67 x 0.80 = 3.74 volts. So the PCM now sees that the car is only running 11 PSI...still well within the limits of an "overboost" CEL.

The problem I am having now though, is that I have a Stage 0 2005, so my TIP still sees the 4.67 volts and it knows something is up. Car runs fine, but it throws a CEL.

So now I'm thinking that I'm going to get a Stage 2 MAP and TIP and plug them in. It will basically do the exact same thing as the DTEC. 20 PSI on a Stage 2/3 MAP is 3.89 volts...to a Stage 0/1 PCM thats 12 PSI. Then with the DTEC I could still go in and add or remove fuel (probably would have to add "signal"). The TIP will also see lower boost levels, because the Stage 2 TIP will read lower to the Stage 0 PCM.