How much performance gain from headers ??

[jondee86]

Quote:That's a full exhaust (obx header, cat, catback) setup vs a oem with back to back dyno testing.

Interesting contribution thanhngo. The OBX is a 4-1 design, so it
is to be expected that it will show some increase at maximum rpm's.

What is more interesting is that it shows some increase in torque from
3000 to 5000 rpm, an area where the 4-1 design is said to be weak.
Maybe some of the improvement can be attributed to the other changes
in the exhaust system ? Overall, I would have been happy with that

The "whyturbothat" page is one I have read several times. There is a lot
of good practical advice in there !!

Thanks Jango. Pulling one gear higher is a sure sign of improved
torque. My smallport is already strong out of corners with just mild cams.
The exhaust is only part of the improvements still to come. Also to be
done are ECU and quad throttle conversion

Cheers... jondee86

[jondee86]

Dimitri Wrote:..... maybe a shorter final gear, or a 7age?

A shorter final gear is a great thing for a race/rally car. Keeps the
engine revs up and effectively "closes up" the gears. Because top
speed has been reduced hitting the limiter in 5th is possible

But, for a road car, the AE86 is already short geared at 4.3:1. Going
to a shorter final gear makes it unsuitable for travelling any distance
at motorway speed. My nearest race track is >100 km from home

A 7AGE ? Hmmm... then why not a 1JZE... or a 1UZ ?? Interesting
as these projects may be, I prefer to stay close to the original concept.
For me the only true AE86 is a free revving 1600

On my first dyno run with nothing but an Apexi intake kit and a 50 dia
exhaust, I made 81 kw (108 hp). My target is 111 kW (150 hp) = 30 kW
to find. This is how I plan to get there...

1. Mild street cams, good for say 8 kW
2. 4-2-1 header, good for say 5 kW
3. Modified head with small increase in compression. Say 8 kW
4. Quad throttle conversion with trumpets. Say 5 kW
5. Programmeable ECU, GZE CAS and coils. Say 5 kW

That's 31 kW without counting any of the small mods like pulleys and
exhaust etc., that can give an extra kW or two. From the research I have
done, I don't think any of these gains are unrealistic. And if one mod
comes up short, another may give more than expected

Cheers... jondee86

[MartinS]

Think, that is realstic if not a 'tiny-bit' pessimistic.
How mild is mild for you?

Regards Martin

[robokill]

1. Mild street cams, good for say 8 kW
2. 4-2-1 header, good for say 5 kW
3. Modified head with small increase in compression. Say 8 kW
4. Quad throttle conversion with trumpets. Say 5 kW
5. Programmeable ECU, GZE CAS and coils. Say 5 kW


This doesn't work as simple as stated. It all depends on how the engine is. (also its diffrent per engine)

Lets say you have a stock head. Than cams will help less than when you have a worked head. This also counts for headers .

If you modify the head properly and chance the cams I was able to make 133.4 whp with a standard header but modifed exhaust (after the 2 piece)

Lets say good headers and some itb's will help alot more once you already achieved a better standard setup.

Also remember that you don't want to stress the engine. So while thinking of these setups keepthat in mind!

[jondee86]

MartinS Wrote:How mild is mild for you ?

Colt Cams C.709 I.S.
223 deg duration @ 0.050" lift; advertised duration 261 deg; lift 0.326"
Inlet and exhaust cams the same.

I bought them because they are a straight "drop-in" and run with the
factory ECU. They are in the car now, and I hope to get back on the
dyno in the next week or two. See if they make 8 kW :wink:

Robokill I understand that there are a lot of variables involved
in making this work. That's why I won't be too upset if any one mod
does not make as much power as I expected. However, I hope that by
taking a dyno reading after each mod, I can provide some hard data
that will be of benefit to others planning their own improvements.

Cheers... jondee86

[cavey]

I just thought of something, maybe it's redundant, but change of oil and some fresh sparkplugs help with freeing up some HP's (according to my buttdyno anyways).

[jondee86]

cavey Wrote:... a change of oil and some fresh sparkplugs help with freeing up
some HP's (according to my buttdyno anyways).

Sure... there are a whole heap of small mods that help to make an
extra kW or two...

- underdrive pulleys for waterpump and alternator
- low viscosity synthetic oil
- premium spark plugs
- thermal gasket for intake manifold
- remove the viscous fan
- low restriction exhaust
- blueprinted (port matched) manifolds
- cold air box etc...

I will probably do most of these when the major mods have been
completed. Better to make one mod at a time when you are trying
to measure the improvement.

Cheers... jondee86

[speed-inc]

Hi guys

I have a few things on my Ae86:
oversize pistons (about 1600cc)
custom header 4-1
Kakimoto Exhaust
lighter flywheel
lighter pulleys
HKS air filter

These are roughly the engine mods.

Compared to a bone stock Ae86 (which I was driving everyday) this setup revs up way better. There is more power and torque. I have no numbers on this though.

Tuning a 4age is just a costly experience and you will never have the same money/power ratio like with a turbo car.

What I can advise you on get a quality header. They will work.
Just remember how good all the japanese headers are tested and developed. R+D at all those facilities is extensive.
In comparison to OBX which are just copies of other brands.

My bet for best performance would be Toda. They have years and years of experience racing the 4ag in various racing series. It is expensive though.

I would advise people though on going after the handling first on our cars. This makes a much bigger improvement for money.

Cheers

[F0Bman]

Header is a great piece to have, but I think that the Electric Fan is a better thing to get.

[drako323]

Hi guys, I hope you don't mind me bringing up this subject again!

I've recently bought a JDM stainless steel header from e-bay. It is 4-2-1, 1.5'' at the engine gasket, 2.25'' at the other end. It was only 90 dollars so I thought I'd try it. It actually is very good looking, the curves are smooth and the welding is perfect. My custom exhaust maker wouldn't believe it costs so little! But, unfortunately...it doesn't fit!!! It actually gets into contact with the car floor (under the accelerator) just for half an inch or so.

Anyway, do you think that by cutting, re-curving and welding so as to pass clean under the car it would affect performance?

Also, I too have the 261degree camshafts you mentioned along with trd adjustable pulleys. I tried it on a dastek dyno and it made between 129-135bhp, depending on the pulley setting. The car otherwise had OEM header, custom exhaust, hks style air filter, trd oil filter and iridium spark plugs. It had at the time around 220000km without any kind of rebuild. So now I reinstalled the OEM intake camshaft, because it wasn't worth the power gain: too high fuel consumption (average 13l/100km) and too high emissions...need a programmable ecu to work correctly.