[rwicks10]

Hi there, I was just wondering what the general consensus was on running headers on a J20A? I will be upgrading my system to a 2 1/4 press bent system with a hi flow cat. Performance / economy wise are headers worth the extra money? It seems as though the standard manifolds are considered to be sufficient on the H20's. Any opinions would be appreciated. Cheers, Rwicks10

[Fatzook]

The J20 headers are very prone to cracking. So its only a matter of time before you will HAVE to fit extractors, so just do it now.

The H20 headers are considered sufficient because nobody makes aftermarket headers for the H20

[Taylor74]

Fatzook wrote:

The J20 headers are very prone to cracking. So its only a matter of time before you will HAVE to fit extractors, so just do it now.

The H20 headers are considered sufficient because nobody makes aftermarket headers for the H20

J20 extractors are the way to go.

If you want to improve the H20 fit the engine pipe from the H25 and build the exhaust further back, they flow heaps better as they dont bottle up at the cat and will bolt straight to the H20 manifolds

[30ONA]

Why do off the shelf headers blank off the EGR? I've had headers since I bought the car and only just noticed the header plate blocks the EGR pipe in the head.

Is there any reason not to retro fit a pipe from the headers to the EGR? Perhaps this is why I notice a loss of power on 91 RON fuel compared to 95RON. Cylinder temps to high.

[Gwagensteve]

Blanking EGR is normal with aftermarket extractors.
EGR raises cylinder temperature, it doesn’t lower it.
The reason your car has less power on 91 than 95 is because there’s 4 points more octane in 95.

[fordem]

Gwagensteve wrote:

EGR raises cylinder temperature, it doesn’t lower it.

As far as I know, it's the other way around - EGR introduces exhaust gases as an "inert" gas to reduce cylinder temperatures and so reduce Nox emissions.

[Gwagensteve]

Right you are. Just did some reading on the topic.

It still won’t have a noticeable effect on performance though.

[30ONA]

Still no answer to the questing though. I've seen headers with the egr pipe, but only a few. Why don't they put them on?

I was also thinking as my car should run on 91 but runs poorly on it, maybe that's because the cylinder temps are higher than stock because the egr is blanked and the 95 helps lower the temps. So maybe if i had the egr working i could run 91 with more success.

[fordem]

I'd be more focused on ignition timing - is it set correctly? Does your car have a knock sensor? If you have a knock sensor do you have an OBD2 scanner that can display the ignition advance - how does it differ when you run 91 as against 95?

[zook ute]

30ONA wrote:

Still no answer to the questing though. I've seen headers with the egr pipe, but only a few. Why don't they put them on?

I was also thinking as my car should run on 91 but runs poorly on it, maybe that's because the cylinder temps are higher than stock because the egr is blanked and the 95 helps lower the temps. So maybe if i had the egr working i could run 91 with more success.

Do yourself a favour and stop trying to run your car on 91 ron fuel, I won't even put 91 in my lawnmower.

[30ONA]

zook ute wrote:

30ONA wrote:

Still no answer to the questing though. I've seen headers with the egr pipe, but only a few. Why don't they put them on?

I was also thinking as my car should run on 91 but runs poorly on it, maybe that's because the cylinder temps are higher than stock because the egr is blanked and the 95 helps lower the temps. So maybe if i had the egr working i could run 91 with more success.

Do yourself a favour and stop trying to run your car on 91 ron fuel, I won't even put 91 in my lawnmower.

My goal isn't to run 91. It was an observation that I thought may have been contributed by a blocked egr system. I can't find any conclusive evidence that supports why you should delete the egr.

[fordem]

30ONA wrote:

My goal isn't to run 91.

That's not what you're saying here.

30ONA wrote:

I was also thinking as my car should run on 91 but runs poorly on it, maybe that's because the cylinder temps are higher than stock because the egr is blanked and the 95 helps lower the temps. So maybe if i had the egr working i could run 91 with more success.

[Gwagensteve]

You’re going to continue to be frustrated by the responses you’re getting in the thread, because you’re barking up the wrong tree. Do some more reading about how and when EGR works- it’s used to reduce NOX- it’s an emissions tool. Mostly it will be used at idle and under light throttle conditions and will be trimmed by the O2 sensor. NOX is a result of the very lean (and therefore very hot) combustion caused when manufacturers are chasing fuel economy. The amount of EGR introduced is small and when it operates will depend on the O2 sensor. Under acceleration EGR will be disabled because under acceleration the car runs around stoich, so isn’t producing NOX, so doesn’t need egr and conversely you don’t want an inert gas in the chamber you want air and fuel.

95 octane doesn’t “cool“ cylinders. Crudely, it burns slower and therefore liberates more energy as it does so. That’s the opposite of burning cooler. Conversely, it’s harder to ignite. I’m not even sure a J20 is mapped for 95 or has any idea what fuel is in it. If the car runs substantially better on 95 that’s an indication of another problem, probably ignition related. The difference in performance between 91 and 95 would be almost undetectable. And I can assure you if someone switched fuel in your car (assuming there was no problem) and you didn’t know you’d never detect it.

Your problem is not related to the deletion of EGR. If you don’t believe me put the stock manifold back on or find some extractors with the egr fitted and swap them in.

[fordem]

Gwagensteve wrote:

I’m not even sure a J20 is mapped for 95 or has any idea what fuel is in it. If the car runs substantially better on 95 that’s an indication of another problem, probably ignition related.

This is why I asked if there was a knock sensor - early J20s don't have it, later ones do - the ECU doesn't know what fuel is in the tank, but if it detects preignition caused by a lower octane fuel, it will reduce the amount of advance to eliminate the preignition.

Quote:

The difference in performance between 91 and 95 would be almost undetectable. And I can assure you if someone switched fuel in your car (assuming there was no problem) and you didn’t know you’d never detect it.

This may not be entirely accurate - I'm not certain what the actual octane numbers we get here are, but when I was a youngster, all filling stations here offered two grades for gasoline, regular & super, at some point we switched to unleaded gasoline with only one grade available, super - a year or two back, one of the three filling station chains started offering a lower octane fuel, and the ladies in my family learned through a moment of inattention, that the car (a JB420) does not run well on "fuel save".

Based on "seat-of-the-pants" experience gained over the years when we had only grade of gasoline, setting the ignition timing 5~10* ahead of the recommended settings made for a much more lively engine, because there was no alternative paying for the high octane fuel, it was essentially a "free" performance upgrade, and widely done. Because of that experience, if the ECU retards the ignition timing to suit the lower octane fuel, I would expect it to be noticeable.

It is theoretically possible that the car has an underlying condition, causing it to not run well on the lower octane fuel, but as it runs fine on the "V-Power", my solution is simple, don't put the fuel save in it.

[Fatzook]

Anecdotal contribution only, but I've owned a wide range of suzuki models over the years, cars and 4wd, and all of them have operated better on 95 or 98. Some experienced audible detonation on 91, and others just ran smoother on the higher octane fuels. My swift sport was 98 only though, so it doesn't count I guess.

[Gwagensteve]

Interesting. I wonder if that implies Suzuki’s calibration is a bit sloppy for Australian 91 octane. “Regular“ fuel in japan must exceed 89 octane and premium must exceed 96. Audible detonation on 91 might imply suzuki calibrate for “Premium” fuel for the AU market.

[30ONA]

I think I want to get a pipe fitted to have my egr working in any case.

[alien]

Fatzook wrote:

Anecdotal contribution only, but I've owned a wide range of suzuki models over the years, cars and 4wd, and all of them have operated better on 95 or 98. Some experienced audible detonation on 91, and others just ran smoother on the higher octane fuels. My swift sport was 98 only though, so it doesn't count I guess.

I've had several g16's now and ALL of them ping on 91 in summer especially. 95 usually solves it, but 98 always does.. I usually run a tank of 98 through every 3rd or 4th tank as well, in the hope that some of the marketing spin around the additives in 98 removing some carbon are true. lol

[Fatzook]

Gwagensteve wrote:

Interesting. I wonder if that implies Suzuki’s calibration is a bit sloppy for Australian 91 octane. “Regular“ fuel in japan must exceed 89 octane and premium must exceed 96. Audible detonation on 91 might imply suzuki calibrate for “Premium” fuel for the AU market.

Steve i believe the lowest grade of unleaded petrol in Japan is closer to our 98 octane.

[Fatzook]

alien wrote:

I usually run a tank of 98 through every 3rd or 4th tank as well, in the hope that some of the marketing spin around the additives in 98 removing some carbon are true. lol

[fordem]

alien wrote:

I usually run a tank of 98 through every 3rd or 4th tank as well, in the hope that some of the marketing spin around the additives in 98 removing some carbon are true. lol

If you have a concern about carbon build up look for an additive with high levels of PEA (Poly Ether Amines), Chevron Techron, Amsoil PI, or CRC's GDI-IVD - note - the CRC product is not a fuel system additive, it's an aerosol designed to be sprayed into the intake on GDI engines, to get the carbon off the back of the intake valves, which do not get washed by the incoming fuel as would occur with port fuel injection.

One of the three fuel distribution chains here does not sell "additivized" fuel, a lot of people use it because it is government owned and the price of fuel is lower than the others, and it is widely believed that vehicles using that fuel are more likely to have problems - anecdotal evidence has numerous reports of vehicles developing problems shortly after being refueled. I can't definitively say that the problems are caused by the lack of an additive package and I should mention that not everyone is aware that the fuel does not have an additive package, I'm aware of it because I have reasonably good contacts within the industry.

Going back to the pre-ignition side of things, the American Petroleum Institute (the people behind the API service classifications for motor oils) have just release a new API level (SP), one of the features of which is it is intended for turbo charged GDI engines where LSPI (Low Speed Pre Ignition) has started to become a problem. I don't know if it's on the shelves here yet, but I'll be looking for it to do my next round of oil changes.