Lexiss_sc430

iTrader: (2)

I am kinda left confused.....

I hope someone here will be able to shine some light on how my pre and post header numbers are pretty much the same.

Once again thank you to Steve from SR Motor Cars in Gardena, it is always a pleasure dealing with him.

With an airbox mod and K & N filter, muffler delete, and a SAFC Tune here are my numbers;

Type of dyno: Dynojet
Run conditions:
Temp 76.3
Bars 1024.6
Humid 18%


MAX POWER = 262.5
MAX TQ = 279.1

Now with S & S Headers installed

Type of dyno: Dynojet
Run conditions:
Temp 91.7
Bars 1026.95
Humid 9%


MAX RW POWER = 265
MAX RW TQ = 284




With a 21% Drive train loss factor I should be making

318 HP and 343 TQ at the engine



Now the question I have is how the hell did the headers only give me 3 hp and 5 tq, that can’t be right.... cant it?




edit: Attached Dyno Runs


1st graph is before the headers





2nd is the most recent one





After looking at the graphs more carefully I can see that the mid range TQ #'s have actually improved and that is where I am noticing the gains.




DYNO SHEETS WITH RPM
BEFORE AND AFTER

PHXSC

Ambient temp.?
Your first run was at 76.3, second was 91.7, if I interpret the results correctly.
15 degrees = how much HP?
thanks for posting your results - I've been waiting....and like you, I was hoping for better

CAMAracer

iTrader: (1)

The real question is, "Was all the 'power' you felt right after you finished the install actually there?"

Hehe, I'm joking. I'll post my dyno results in two weeks when I finally have time to take my car to the shop... *crossing fingers* that it isn't disappointing too....

Lexiss_sc430

iTrader: (2)

I know there was a performance gain because I have ran against a few different cars and I am about 1 car length faster than I was before.

stevechumo

iTrader: (5)

For some reason I calculated your bhp to 335.44 from 265 / .79 because you deduct 21% out of the total bhp. 335 bhp is actually very nice for the bolt-on mods. It's just a calculation, but I'm sure you feel a big difference when you floor the gas pedal. Headers only don't usually give a lot of power, unless you go with a complete exhaust system. The catalyters and the small stock pipe diameter on each side really restrict the flow, cause backpressure, and thus don't give the maximum power, although you already deleted the mufflers.

JMSxChris

iTrader: (1)

If you still have both dyno graphs, compare the two or have the shop print you an overlayed version if they still have both run files. The a differences throughout the rpm range would tell you more than just looking at your peak figure, and will probably explain the performance gain you feel you're seeing when running other cars. Also, post the graphs if you can, I'm sure many here would love to see them. Thanks!

Lexiss_sc430

iTrader: (2)

posted dyno runs

stevechumo

iTrader: (5)

I'd love to see the dyno graph that has the X axis showing the RPM and the Y axis showing the hp/tq. That'll tell much more about the power curve when how soon the power kicks in and how efficient it is. It's hard to know with the mph graph because you may have full power at 60 mph or just some power at 130 mph. It's because the power corresponds to the RPM of how fast the engine turns to make power.

p-bateman

you are running a high flow header setup INTO a serious BOTTLENECK of a stock exhaust! have you seen how tiny the stock exhaust gets when it's crimped under the rear diff? you'd have to get a full catback and hi-flow cats to truly see what those headers do. a true cold air would help as well. S-AFC's are not very good programmers either. i've read that the Lexus ECU eventually starts compensating for the changes sent from the S-AFC. regardless, with a 4.3L V8, it's like a muscle car, if you want more power, you gotta open her up, and she'll be LOUD but more powerful.

p-bateman

the stock cats are so stuffed you can't even see light through the ends if you hold one up into the sun!

also forgot to mention, i've seen the insides of the resonators as well, VERY restrictive.

Lexiss_sc430

iTrader: (2)

POSTED DYNO RUNS WITH RPM's




I spoke to my exhaust guy and he said if I were to replace just the pipes under the axle there might not be any noticeable change. I don't want to deal with deleting the cats but as far as the resonators and piping under the axle goes I am up for suggestions. What do you guys think I should do?

stevechumo

iTrader: (5)

Thanks for posting them up. The power curve looks good, but a little more fine tuning with the SAFC between 2800 - 4800 RPM may yield a more flat power curve. But you may not feel the quick sluggish power because the power keeps climbing up. Or it could be the stock ECU that was trying to readjust the fuel. You can completely eliminate the stock ECU to readjust the parameter by using the O2 sensor simulators, 1 on each side before the cats. They'll trick the ECU into thinking the car runs normally.

You shouldn't eliminate the cats completely. Big ticket right there. Using larger & high flow cats with a complete custom pipes will help a lot. But don't use straight pipes. You'll lose low end with straight pipes. The stock curve has its advantage to keep the power at low end, while still managing to make power at high end. I'd say a dual 2.5" pipes would be perfect. Headers + high flow cats + high flow resonators + high flow muffers + good curves = maximum performance.

The exhaust shop should know each exhaust side shouldn't run independently when the car is a V8 and with no forced induction. They should cross over each other with a X or a H.

JMSxChris

iTrader: (1)

Thank you very much for posting the dyno charts! Its really nice to see the whole story. I was on the fence about purchasing the headers, but the low end hp/torque are really improved under 4000rpm. Overall how do you like how the car drives now? I'm sure it feels alot better with the nice gain that carries though 3000-4000rpm...

Before headers 3000rpm:
131 hp
230 ft/lbs

After headers 3000rpm:
140 hp
245 ft/lbs

Thanks again for posting.

Lexiss_sc430

iTrader: (2)

Honestly the headers are awesome, they gave great consistent power throughout my usual driving range. I am mostly on the streets and I can feel the power on accelerations from light to light.

redliner8

iTrader: (1)

I know this is old, but Lexiss_sc430 (or anyone else) did the SAFC II (which I now believe is the AFC-Neo) make much of a difference with your power? I was considering buying the AFC-Neo but I'm not sure how much of a difference it will make. Any info would be helpful.