Bliggity

Thanks to Kevs98GS4, we did a swap of my stock headers with his ss headers. What a diff!!! Very mild change in exhaust note but the power is def there, I will be doing a dyno run after christmas when I get my neo tuned. Before I tune it I will see what numbers I produced with the headers. I dynoyed my car a couple weeks ago so I will know how much the headers gave me. Getting these bad boys isnt like installing a catback exhaust or intake, you know how you have to kind of guess when you install some things, "I think I feel a diff"? There is no doubt with the ss headers!

Rock-a-Lex

iTrader: (4)

NICE! Can't wait to install mine too! Now get that dyno! I estimate that you should see anywhere from 285-290whp.

Bliggity

That would be sweet! I'm also installing torque master plugs before the dyno run.

JBrady

Excellent

I seem to recall you bought these second hand. My ONLY concern is that you acquired a set that was made before the changes in tube thickness and welding. If not you will probably have cracking problems after 5000 - 10000 miles. There has been no reports of any cracking after the upgrades.

Now, to the POWER!!!

These work very well on the 400s but are IMO mandatory on the 430s. The 430 is a bigger engine with more restrictive factory manifolds. You should feel the power and torque as well as the throttle response at virtually any and all RPMs.

As far as dyno numbers... unless you run back to back identical runs INCLUDING checking for temperature of intake air and coolant, ignition timing and ECU mapping getting accurate true data is really hard. 10-20rwhp is reasonable but if you could measure the responsiveness and the dynamic condition known to high end engine builders as "transient response" (the rate at which each combustion cycle begins and completes based on the rate of RPM acceleration... BTW is different in each gear) IF you could accurately measure this you would see much more interesting data. In fact the WAY the car feels is definitely a better indication than peak power gains.

A good example is the dyno of a supercharged GS430. Before and after gains were 26rwhp and 15rwtq. Let me explain why that is NOT EVEN CLOSE to the whole picture.

https://www.clublexus.com/forums/per...headers-3.html

First of all the car dropped half a pound of boost from 6.5 to 6.0 psi. This is due the engine flowing better vs. the same compressor setting. If you adjust the boost back to 6.5 psi the peak gains would be substantially higher.

But the REAL story is in the mid range.

The Mustang dyno used (typically reads lower than dynojet) did not get engine RPM so it was listed only in MPH.

At the lowest speed recorded, 66mph, the car had already gained 9rwhp and 7rwtq. Remember this a centrifugal supercharged car that will make very little to no boost at low RPM so this is would be fairly similar to a stock cars gain.

The following supercharged header gains were recorded:

66mph = 9rwhp 7 rwtq
77mph = 10rwhp 15rwtq
81mph = 13rwhp 15rwtq
83mph = 14rwhp 22rwtq
94mph = 19rwhp 20rwtq
100mph = 20rwhp 25rwtq
108mph = 34rwhp 32rwtq
111mph = 43rwhp 37rwtq
117mph = 28rwhp 24rwtq

So, IMO the biggest gain recorded was 43rwhp and 37rwtq

One further note of interest... these numbers were recorded with the STOCK Y pipe with 1.97" primaries and 2.36" single center pipe AND 3rd catalyst.

For those interested a Y pipe upgrade is being looked at but for now on stock engines I recommend the STOCK Y pipe. The upgrade will be SLIGHTLY larger tubing to allow for more flow but without compromising the excellent low and mid range power that the stock pipe gets with these headers.

So, the gains you are feeling are MUCH more important the peak numbers recorded on a dynojet.

Having fun yet?

Rock-a-Lex

iTrader: (4)

Great post J!

Bliggity

I was told the headers are from the second batch, and the shop that installed them knew of the cracking welds and the mechanic said the welds looked great and no need to be re-welded. And you are spot on about the power gain in virtually the whole rpm range.

FinLIFE

iTrader: (8)

did you do the install yourself? how long did it take?

evil00017

Hey bliggity do you and rock a lex have similar mods?