GEEZUS... This was a post about the SL55 Y pipe and why it wasn't producing the expected HP... How much more clear do I have to make my posts ?

UNLESS THE ECU IS TUNED TO THE ADDED AIR, OR ADDED GAS, IT WILL NOT PRODUCE THE EXPECTED HP GAINS !!!

 

Can you explain the LOSS? More air without the added fuel will not hurt power, will it? Wouldn't it actually cause a lean condition and help power? Neither of which was shown in the graph.

If in fact the car does 'fatten up' automatically due to more air, it doesn't show that either.

No need to get bent out of shape.

SQ

 

Shawn,

Get some miles on that intake and let us know if you feel an improvement. Talking numbers is always pointless. Let the facts and 1/4 mile times do all the talking. I guarantee you should run a high 12 and gain a few mph with a decent intake on these cars. Several board members have done it including myself. This ECU can and will adapt to mods it just takes time.

 

Can anyone confirm if the Air/Fuel mixture remained in "safe" parameters with the SL55 Y pipe ?

I was looking at the "Stock" set up again today and the Standard pipes to the air boxes look very restrictive as they narrow between the openings. Maybe moding the SL55 pipes and fitting to the stock Y pipe could return some inprovement ???

I would be very keen to hear if it does improve after a few 100 miles and is re-run on the rolling road asECU's take far longer to "advance" timing etc than they do to knock it back.

Shawn, are you going to refit and test again after a few 100 miles ?
Also, will you be getting the SL55 pipes too next time ?

Cheers,
Si

 

I will likely order the SL55 pipes, or try to make my own out of silicon couplers that are less restrictive.

I put almost 200 miles on it before I dyno'd it, so it should've been somewhat 'ready' for it, IMHO.

I will try it at the track the next time out (maybe this wednesday). We'll see what happens.

SQ

 

Hi Shawn,

Thanks for the reply. Very strange results though. Maybe being able to get full throttle will show if this mod is able to really help the breathing. To reduce power, just doesn't make sense.

Please post when you have tried larger pipes on it and the track test results with it fitted either way.

Did the A/F mixture stay in safe linilts as you had it ?

Cheers,

Si

 

The A/F looks great both ways.

SQ

 

I don't wanna derail this thread, but I have a couple of "for dummies" questions:

Someone above mentioned that the ECU will always adjust the air to fuel ratio to 14.7. And someone else said that the ideal A/F is in the ~12.5 range. And someone else said 14.7 was safer. I don't get it.

If 12.5 is ideal, why wouldn't the ECU adjust to 12.5?

Why is 14.7 safer?


Also, someone said that the HP gains of intake mods won't produce the expected gains without an ECU remap.

How is it that the people that initially tested the Need Wings intake got about 25 HP out of it without an ECU remap?

Does this mean there are more HP to gain with a Needs Wings intake AND an ECU remap?

Please don't take my questions as doubting anyone's word or knowledge on the subject. I know very little about dynos, intakes, A/F ratios, and ECU maps. So I'm just trying to figure it all out.

 

Shawn
loss in power with the wider SL55Y pipe will only occur if odd air turbulance/flow starts to happen. The pipe might be wider but there is a lip or angle somewhere in the piping that is effecting the flow of air that the engine actually sees. The computer will more then compensate for more air CHI- towns car with needswings was rich at 11.1 Besides if the car ran lean you would develope more HP before the engine went south, which won't happen on ECM cars. Too many safety features.

 

14.7:1 is ideal for emissions... NOT power. That is the primary target for all modern engine control units.

If you want power, you will have to retune the ECU to put more fuel (Closer to 12:1) into the engine at almost any given RPM. I would say change the graph that kicks in under load and not the cruising or neutral power graph.

I can see what HDDP is saying though. The fuel curves programmed into that ECU that work under WOT are not calibrated for that extra air coming in and will suffer (leaner than 12:1) during long WOT times. Also, if the mixture becomes lean enough to cause detonation, the ECU will retard the timing, which will result in further power loss.

Cheers!

 

Wouldn't this 'change' from the ECU show up on the A/F reading from the dyno?

 

Were you monitoring the timing ? The ECU will adjust the timing advance / retard based on certain factors of AFR to kee the engine running as close to stoiciometric as possible...

It sounds like many of you don't understand how integrated all of the sensors are with this engine and how all of them will manipulate timing and AFR...

If you take a look at one of my posts somewhere on this forum, you'll find data sheets that were done under track conditions... We kept scratching our heads as to why the timing kept retarding itself and the AFR kept hovering around that 14 range... Even though I was stuffing huge amounts of air into the TB and running a crazy mixture of fuel that should have sent the engine into a choked-up rich state... The ECU tried so hard to reduce the CARB emissions, that it retarded the timing at some points on the track, to -40 degrees...

This is when I started talking to the Bosch guys and they gave me the answers that I have been trying to share with you people, but everybody seems to have some sort of other opinion...

So, in the future... I'll make sure that I don't share any of the information with this forum... Because it seems that these NEWBIES know more...

 

??? Where did you read that it was safer ??? Without being rude, read this http://en.wikipedia.org/wiki/Stoichiometry After you get done... you'll understand that the engine tries to maintain perfect combustion to prevent pollutants... And this engine does a really good job of it... That perfect combustion is 14.7:1 But that's not perfect for maximum HP...

 

Seems a bit harsh...

 

I'm not always right, but I don't get bent out of shape if someone corrects me .
I was just trying to keep others from learning incorrect info about internal cumbustion engines which would make them look bad if they relayed it to others who are properly informed.
If you queation my credentails here is my web site to my side business: www.ap-engines.com . In my day job I am the engine builder for a championship Nextel Cup team. I sure wouldn't get upset if you corrected me about film making

 

HDDP,

No, I did not monitor the timing. However, I did monitor the A/F ratio and the only time it was anywhere near the 14.7 area was when the car was at idle or very light throttle.

I believe you said this was because there was not a long enough WOT run and the ECU did not have time to bring the AFR back up.

Unfortunately, not everyone has the money to throw at electronics, custom tuning, etc...so they hope to learn from others who have come to their conclusions through expensive trial and error, research, and good ol' experience.

It is obviously your decision if you choose to stop helping. Some people are proud to share, some are not. It is free information and no one is obligated.

There are some very intelligent and knowledgeable people who make pitiful teachers. Sadly, because of all of the other useless BS involved in all of these posts...I feel like I've done more sifting than learning.

SQ

 

Cheers Shawn, The last thing I would want is to hole a piston etc.

 

Sorry, folks. I should have quoted the part I didn't understand. Here where Jeremy is talking about lean vs. rich and WOT, I don't really understand his last statement about running rich being safe.

Does he just mean safe for the atmosphere, as in low polutants? Or safe for the engine, as in no damaged parts?

 

Thanks HDDP!

 

Safe for the engine.