Lexus IS Forum banner

1 - 20 of 68 Posts

·
Registered
Joined
·
4,925 Posts
Discussion Starter #1
So I have realized that no matter what, as an untuned ECU, there are no competitors with the SRT intake. Their blackboxes do the job, putting out the best gains for our cars.

Now, I am wondering without the race ECU, has anyone dynoed or felt what gains the SRT pipe and filter itself feels like? Or does it only do good with the pretuned blackbox?

As some of you guys know, SRT utilizes the AFE gold filter, the one with 7 pleats.
AFE= Advanced Flow Engineering, located in Corona, CA.

Apparently they did now know about the amazing SRT intake gains, they thought it was just another company using AFE filters, like Injen used to. Their applications are usually for Euro or DOmestic cars, so they didnt make one for IS300. However other companies like Injen found out how better flowing their filters were, and decided to use it under their name.

So I have spoken with one of the main guys there, and they are willing to request a fabrication for our cars, so that would include the pipe and heatshield, or box, blah blah blah.

They will try to test the gains of their design of the "SRT Intake", without the SRT ECU, so when we tune we emanage or SAFC, we can still get just as good gains, but we tune it out driving conditions of where we live, and how we drive, since SRT was made in east coast.

I will keep you guys updated, and I hope to see an intake just as strong, but doesnt require race ECU and costs $400-$500.

-Aaron :p
 

·
Registered
Joined
·
3,005 Posts
i remember reading something about you cannot run the srt intake without the blackbox because of the diameter of the piping is bigger and because of that the air flow is a lot different than what the ECU normally reads, thus it will run sluggish because the ECU thinks that the amount of air takened in is not right...
 

·
Registered
Joined
·
8,142 Posts
To run a wider intake pipe your MAF sensor must be recalibrated.
I have not the slightest clue how that is done.

I have a 3in intake sitting at home, however I cant use it since my car rejects it and acts up.
 

·
Registered
Joined
·
989 Posts
well i have the AEM intake which is a 3in and i didnt notice any sluggish power.
 

·
Registered
Joined
·
8,219 Posts
why on earth go through all this trouble just for an intake? THe SRT is proven to work reliably and is readily availiable as well as many other intakes with an SAFC.

All this work is going to take R&D from AFE and thier intakes are going to cost a butload in the beginning to make up for the cost, then after that the price will slightly come down GIVEN that there is a high demand for thier intakes. Using the SRT pipe without electronics simply wont work, the car stalls because of the piping size. So lets say AFE fabricates a pipe just like SRT but a little bit cheaper and sells it with no box, you will STILL need electronics to get it working properly.

Again, i dont see the purpose.
 

·
Premium Member
Joined
·
4,704 Posts
onyxaltezza said:
So I have realized that no matter what, as an untuned ECU, there are no competitors with the SRT intake. Their blackboxes do the job, putting out the best gains for our cars.

Now, I am wondering without the race ECU, has anyone dynoed or felt what gains the SRT pipe and filter itself feels like? Or does it only do good with the pretuned blackbox?

As some of you guys know, SRT utilizes the AFE gold filter, the one with 7 pleats.
AFE= Advanced Flow Engineering, located in Corona, CA.

Apparently they did now know about the amazing SRT intake gains, they thought it was just another company using AFE filters, like Injen used to. Their applications are usually for Euro or DOmestic cars, so they didnt make one for IS300. However other companies like Injen found out how better flowing their filters were, and decided to use it under their name.

So I have spoken with one of the main guys there, and they are willing to request a fabrication for our cars, so that would include the pipe and heatshield, or box, blah blah blah.

They will try to test the gains of their design of the "SRT Intake", without the SRT ECU, so when we tune we emanage or SAFC, we can still get just as good gains, but we tune it out driving conditions of where we live, and how we drive, since SRT was made in east coast.

I will keep you guys updated, and I hope to see an intake just as strong, but doesnt require race ECU and costs $400-$500.

-Aaron :p
+ Rep for taking the NA thing another step forward!!!

now here is my take on it.

The reason why the SRT has a blackbox is not to just tune the car for a better AF ratio though you do get that too as a side result. All cars with a Mass Air sensor measure airflow by using a fixed diameter (that little open circle on the MAF sensor). A thermistor measures the temp of incoming air and a hot wire is kept at a constant temperature in relation to the thermistor. So if you increase the airflow, the hot wire will require more current to mentain its constant temperature (so will it when the air is colder). That change in current is what is used by the computer to measure how much fuel is needed. Now of course the computer determines that by using a conversion where it determines the airflow thru that little circle and multiplies it by a factor to make up for area of the whole tube. If you change the diameter of the tube (ala SRT intake), the area the conputer is claculating for is going to be less than the actual area that the tube has. Think about this; the area of a circle is pi*radius^2, so by changing the diameter by say 4 inchs, you have changed the airflow capabilities of that tube by 2^2. So if you do not conpensate by telling the computer that it should allow for 4 more inches of airflow space, the car will run extremely lean. now if you can tell the computer via modified volt reading from the maf that there is 4 more inches or airspace being used, the computer will put the right amount of fuel to mix with the air. That is what the R-ECU/SAFC does. but the r-ecu goes a step further by telling the computer that actually it isnt 4 more inches of airspace being utilised, its only 3.5 inches. computer uses that info and puts the right amount of fuel but in this case it is less fuel than it would have originally done if it had the right info. So you end up with a leaner situation (which is good for the car's performance this time). So really it is tricking the computer to think all is well and you just have more air moving in (thermistor is reading more air) when in reality it is just more space.

Ok back to what you are doing, if AFE filters flow that much better than what is on the market today, then just swapping to an injen, FIPK etc etc on and tube filter should net you more power. but no "new tube" can actually do that. Oh just add the Apexi SAFC II to it to get similar results as the SRT.

I really dont think the AFE filter flows any better than the K&N filters at all. In fact I am sure that if I can find the K&N cone filter that has the top portion with a filter as well instead of the plastic where the AFE has it, we can get even more airflow on the SRT.

But good luck with that and let us know what you find out. As I said earlier +rep.

EDIT: must show others love before giving to onyxaltezza again, owe you one!

Edit for better clarification on how MAF works you can look at this site with pics. The IS uses the MAF (not vane-vw i think, or vortex sensors).
http://www.autoshop101.com/forms/h34.pdf
 

·
Premium Member
Joined
·
4,704 Posts
van48 said:
well i have the AEM intake which is a 3in and i didnt notice any sluggish power.
just so you know:

Stock pipe is 2.75"
SRT pipe is 3.5"

if AEM is 3 inches, then it is trying to do what SRT has done w/o the electronics (ie get a leaner mixture w/o going over board). I think .25 inch is a little much w/o electronic, no wonder people get cel with the intake. You are right at the edge of what the stock MAF+ecu can compensate for and the slightes difference tube to tube will cause a cel. They should have gone with something a little smaller.
 

·
Banned
Joined
·
12,375 Posts
theres really no point. srt has gotten pretty all you can from an intake setup thru trial and error and years of testing. if it isnt broke, why fix it. if you want more speed or poer, bite the bullet and add some boost.
 

·
Registered
Joined
·
8,219 Posts
what is all this talk about the SRT ecu modifying the MAF signal??? The maf wire on the ECU is not even touched. THe wires that are used are, RPM, power, ground, AF and ignition. The MAF remains untouched. It doesnt screw around with the maf signal. It alters the AF signal based on RPM input into the RACE ECU and makes adjustments accordingly. Its target AFR is 13.5:1

THe AEM intake does not throw CEL's because of its piping diameter what so ever. It throws CEL's because of Air Turbulence caused by piping design. Early Injen intakes were 2.75 inch in diameter and they threw CEL's as well.
 

·
Premium Member
Joined
·
4,704 Posts
mikefate said:
theres really no point. srt has gotten pretty all you can from an intake setup ......
And you know this how?

I ask cos i cannot help but wonder why they went with an intake pipe that is substantially bigger than the throttle body. Since a system is as good as its weakest link, the extra diameter in the piping seems more like a marketing thing???

PS: I have and love the SRT, but sometimes I think the loss of lowend from the much bigger pipe makes intakes like the Joe Z/K&N/etc etc +SAFC II tune a better choice.
 

·
Premium Member
Joined
·
4,704 Posts
Malekreza11 said:
what is all this talk about the SRT ecu modifying the MAF signal??? The maf wire on the ECU is not even touched. THe wires that are used are, RPM, power, ground, AFR and ignition. The MAF remains untouched. It doesnt screw around with the maf signal. It alters the AF signal based on RPM input into the RACE ECU and makes adjustments accordingly. Its target AFR is 13.5:1

THe AEM intake does not throw CEL's because of its piping diameter what so ever. It throws CEL's because of Air Turbulence caused by piping design. Early Injen intakes were 2.75 inch in diameter and they threw CEL's as well.
And how do you think it makes that AF adjustment? Cos I cant really tell from your explanation.

Also on my statement about the AEM, I went off someone who said the AEM were 3 inches in diameter.

the SRT also has quite a bit of turbulence (when you step down so sharply from 3.5-2.75), but by placing the MAF in the position it is in, the turbulence factor is eliminated.
 

·
Registered
Joined
·
3,005 Posts
wow this reminds me of my fluid mechanics class :lol:
 

·
Registered
Joined
·
8,219 Posts
you are greatly mistaken on alot of things.

How does the SRT make AF adjustments?? pretty simple dude. It takes the AF wire on the stock ECU, you cut it, send one end to one wire on the RECU, the other end to the other wire. The RECU modifies the voltage across based on the RPM input and sends it back to the stock ECU for a target AFR of 13.5:1

Piping diameter is not the cause for air turbulence. Piping design and the bends are the cuase for turbulence. If you notice on the SRT, the airscoop is pointed RIGHT at the filter, that SUCKS for turbulence, but if you also notice, its got a deflector infront of the scoop to deflect the air and randomize it so it doesnt cause turbulence and allows the vacuum through the filter to pick up the availiable air.

The AEM is 3 inches in diameter.
 

·
Premium Member
Joined
·
4,704 Posts
isnt the Af wire the Air flow wire? Ie the voltage from the MAF? Also please chime in if you have a SAFC II, is that not the same wire that you cut if you wanted to install the SAFC by the ecu vs by the MAF? I think DAS wil know this ;) (SAFC advocate lol)

But you are right, diameter does not cause turbulence. But note: I did not say that either. I said the sharp drop from 3.5-2.75" will caused turbulence. When you change the diameter on a continues pipe, it will cause some turbulence.
 

·
Premium Member
Joined
·
4,704 Posts
One more thing, the computer in a car CANNOT target a 13.5:1 AF ratio. why? cos our stock O2 sensors cannot do that. It can only read rich or lean! Now if we had a wideband O2 sensor then what you are saying could be right!

thats why under WOT, the car ignores all readings from the O2 sensor (closed loop)

Hmmm or is it open loop? lol forgot which one, but it does ignore the O2 sensor and goes with MAF sensor only.

Also if the AF wire can target 13.5:1 air fuel ratio, then you can use the blackbox from SRT on ANY intake out there and get the target 13.5 air fuel ratio.
 

·
Registered
Joined
·
8,219 Posts
SRT ECU tags these wires..

--Throttle (taps into it)
--RPM Signal (taps into it)
--Ignition Power (taps into it)
--AF Signal (ONE of a few MAF wires)
--Ground

This is the same as a Super AFC.

Keep in mind, the AF is the Airflow wire, but there are other wires pertaining to the Mass air flow sensor that remain completely untouched. Sorry i jumped to conlusions on a couple of things.
 

·
Premium Member
Joined
·
4,704 Posts
Malekreza11 said:
SRT ECU tags these wires..

--Throttle (taps into it)
--RPM Signal (taps into it)
--Ignition Power (taps into it)
--AF Signal (ONE of a few MAF wires)
--Ground

This is the same as a Super AFC.

Keep in mind, the AF is the Airflow wire, but there are other wires pertaining to the Mass air flow sensor. Sorry i jumped to conlusions on a couple of things.
No problem so far as the right info is out there for us to all learn I am cool with it :approve:
 

·
Registered
Joined
·
8,219 Posts
kponti said:
One more thing, the computer in a car CANNOT target a 13.5:1 AF ratio. why? cos our stock O2 sensors cannot do that. It can only read rich or lean! Now if we had a wideband O2 sensor then what you are saying could be right!

thats why under WOT, the car ignores all readings from the O2 sensor (closed loop)

Hmmm or is it open loop? lol forgot which one, but it does ignore the O2 sensor and goes with MAF sensor only.

Also if the AF wire can target 13.5:1 air fuel ratio, then you can use the blackbox from SRT on ANY intake out there and get the target 13.5 air fuel ratio.

i didnt say the car's ECU targets a 13.5 ratio, the result of the modified AF signal is a 13.5:1 ratio, and i am sure that this was SRT's intention when all this was tested on the Dyno.

You are right about altering the AF for sure. Sorry i posted quite blindly on the AF thing earlier.
 
1 - 20 of 68 Posts
Top