Bigger Headers on 2.5

• Stock: 140 RWHP (baseline)
• With just a tune: 170 RWHP - 21% increase over stock,
• With header & tune: 182 RWHP - 30% increase over stock, 7% increase over tune alone

sunny said:

do you still have stock air filter and is o2 sensor still on that exhaust?

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Taz said:

Absolute numbers are good if you can equally compare them. Personally what I like to see are what the gains were relative to baseline.

For example (made up numbers).

• Stock: 140 RWHP (baseline)
• With just a tune: 170 RWHP - 21% increase over stock,
• With header & tune: 182 RWHP - 30% increase over stock, 7% increase over tune alone

So, while I love the headers, incrementally, it doesn't potentially make a lot more than just a tune alone. At the same time, it would likely be the cornerstone to build upon and another ~7% is nothing to sneeze at. So the low-hanging fruit is going with a tune. At the same time, if I go with the headers, I'll need to spend some $$$ on dyno time to get it right or I am leaving HP on the table.

I priced dyno tuning in my area, and I got quotes of a minimum of $500 USD to $1000, depending on the shop I went to. So I'd have to add that into the overall cost. Now if there is a map already that would work with the header for TuneECU then I could save on that expense.

Despite the economics not being as good as I would like, to hit my goal of 200 RWHP, it will likely be necessary. So there is a header about to go in my cart. I am just debating between the stainless or Ti version. I wouldn't mind the few extra pounds weight savings. I am assuming there is no difference in output.

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Paul Bryant said:

US$500-1000 seams excessive !
The dyno tune done here by BRM was around NZ$500, that's US$306

When you say a tune only, that would be a "canned" tune, so not nessarily 100% correct for your individual bike, fuel, ambiant conditions, right ?
In the past people would ask me for a tune to go with my headers, this often caused grief as the tune that I had here for NZ conditions, fuel etc didn't work so well with the different fuels etc Globally.
I no longer do this.

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dougl said:

Richard Albans posted a video here in which he said the stock headers were the biggest restriction.

How did you dyno tune it? Power Commander or directly with Tuneecu? Not everyone has access to dyno tuners. Can you offer your tune as an accessory to your hardware.

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Paul Bryant said:

I'm not sure what programs Brett uses to access the ECU.

No I don't supply tune, as mentioned in another thread, a tune I would supply is for NZ conditions, fuel etc.
This has caused grief in other parts of the world with the different fuels etc.
A canned tune is never 100% correct for your particular bike, fuel, climate etc.

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Paul Bryant said:

Using the figure of 25% loss that makes the real world RWHP of 182.5, 250 HP at the crank. Do ya think ?
A 20% loss would mean that RWHP of 182.5 would be 230 HP at the crank.

Choose your own numbers.
What ever the crank HP is, the RWHP as done at BRM Tuning in Paeroa, NZ was 182.5

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dfresh said:

Besides performance benefits, does the larger headers and difference in design significantly reduce the heat output or is the difference in that regard negligible? Just curious.

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Paul Bryant said:

There's a lot of "interesting" opinions stated here.
We built a header for the 2.5, had it tuned properly, 215 crank HP. That's a 35% increase over stock.


No other mods.
So for those who say "just a header won't make much difference" you're way off base.

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dfresh said:

Besides performance benefits, does the larger headers and difference in design significantly reduce the heat output or is the difference in that regard negligible? Just curious.

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