trbopooh

John, I am unfamiliar with the SRT intake and ecu. Is the SRT ecu calibrated to only the intake? If you had exhaust and headers, the ecu wouldn't compensate for this would it? Can someone familiar with the SRT chime in?

DaveGS4

iTrader: (2)

It definitely *IS* tuneable, but only by Mo at the SRT facility. You're certainly going to be correct about the standard settings not being optimal for headers unless it's just blind luck.

morris

iTrader: (2)

Yes I guess you are right Dave, but in my book if you have to take the whole shootin match back to the manufacturer, that doesnt count. I guess when I think of tuneable, I think of it as tuneable by the enduser or by your average local shop.

Sort of along the lilnes of a SAFC or AEM unit.

trbopooh

Dave and Morris,

I suppose it's kind of redundant for the people with FI getting these because they would have to retune, but do you think that people will see better numbers if they used something like SAFC along with intake, exhaust, and headers.

Thanks,

Mike

GILLEXUS

iTrader: (14)

So did your header ,cats and Y- pipe all line up? Did you have to make an minor mods to bolt your Y-pipe to you cat or exhaust?

jp430

Just got mine last week, having them installed this weekend. Should help with my SC setup. I am going to dyno the car before and after headers are installed.

DaveGS4

iTrader: (2)

Yes, definitely. IMO you'd still need to dyno tune to make it most effective


Well, we'll just have to disagree . You also have the option to dyno at your local shop and mail it back with your dyno results (incl air fuel) and just clip the ECU back in. LOTs of tuners do that for German cars, etc. I grant that its more of a pain and having the adjust in-car is somewhat more flexible, but it is certainly tuneable just like an SAFC or AEM unit at the end of the day.

trbopooh

Nope, I didn't do the y pipe. Is that what you are asking? Everything fits fine except you might have to make some adjustments. I had to grind off part of the ring on my cat to make it fit right. John said gawd didn't have that issue. Read his post after my install to see how gawd's install went. BTW, are the instructions to hook up the SAFC the same as the SRT ecu?

Thanks,

Mike

trbopooh

I definitely think so. I'm going FI soon and didn't want to spend money just to dyno results and dyno again after SC install.

Mike

DASHOCKER

iTrader: (2)

Can't wait for the dyno numbers. I've been waiting for this mod for our cars for an eternity

GILLEXUS

iTrader: (14)

The SRT's ECU hook up is the same for the SAFC, except for the rpm signal. Which do you have S-AFC II or I? Check out GURU's diagram for the GS400 S-AFC II. I'll see if I can find it.

What did you hook up to the cats after the header if you did not use the stock Y-pipe?

Pearlpower

iTrader: (2)

Hmmm, interesting the progress that has been made. Great job jBrady and thank you for your efforts. I would certainly be interested in a set for my SC if space allows. I will have to go out and compare the two cars in the garage and looking forward to those dynos.
Lee

GILLEXUS

iTrader: (14)

trbopooh, here is that post for your S-AFC

https://www.clublexus.com/forums/sho...95&postcount=5

GILLEXUS

iTrader: (14)

That will be really great.
Glad that you will have the opportunity to do this. This will help a lot of us to see exactly how much and where in the power band the header affects the car. And as soon as someone w/ a non FI car dynos it w/ pre and post header #'s. This will give us a great deal of info.
I'm guessing that there will be quite a bit difference w/ the headers on the a FI car w/ exhaust sytem than non-FI. Just my $.02

JBrady

I do not have an SRT but here is my understanding of it and the stock MAF:

Stock A/F ratios are tuned "safe" as to tolerate a wide range of owners potential use and abuse such as running 87 octane and pulling a trailer. Most performance people understand that more power will be generated the LEANER the A/F ratio is up to the point of detonation. Hence the tuning term "lean is mean" I.E. makes more power but is a dangerous tune.

So, if you take an SAFC or other end user adjustable device and lean out the factory fuel ratio you will gain power. The same generally applies to advancing the ignition timing. So, even without more air flow capacity the modified tune can increase power.

The SRT intake is a larger diameter than stock tube into which the stock MAFsensor is placed. Since the tube is larger in diameter this would create a VERY lean running condition with no other changes. The MAF element creates a signal assuming the stock diameter tubing. Bigger tubing, more flow for any given signal.

Now, the SRT ECU piggyback does two things, it corrects the signal to account for the increased flow past the MAF element AND it leans the mixture somewhat. These are actually competing tuning directions. The bigger tube leaned it already so the ECU actually must richen the mixture to bring it back to factory ratios. So, they just do not richen quite as much and end up with a slightly leaner and more powerful tune. The larger pipe diameter reduces restriction around the MAF so air flow potential is increased.

Now, once your MAF is reading correctly it will AUTOMATICALLY adjust the A/F ratio as the mass air flow changes. The installation of headers and the subsequent increase in total flow mearly will be compensated by the MAFs preset ratio. In theory the MAF will maintain (up to its flow capacity) the correct fuel flow.

In the case with gawd's engine and SRT for some reason his is running WAY too rich. For whatever reason his MAF is signalling is incorrect. Installing the headers in theory should not significantly alter the A/F ratio as any flow increase will be met with fuel increase. It is always nice to optimize your tuning but I would have no concerns whatsoever running the headers on either a stock MAF or SRT set up without tuning. Of course that statement assumes either setup is in fact tuned correctly before the header install. This is the SAME reason that adding the K&N system does not require tuning.