5zigen exhaust and headers

[Apu]

Dann, what about issues with brake vacuum? Probably less of a noticeable issue here but we have a lot of multistorey carparks in Singapore and one of the things I realized with higher lift cams was that I'd "run out of brake"when coasting down several floors and have to blip the throttle every now and then.

[NitroDann]

Never heard of that issue.
Id have to guess it wasnt the cams....

With stock cams you might idle at 25kpa, big lumpy ones might idle at 35kpa... Either way its still constantly pulling vacuum, it shouldnt 'run out'?

Dann

[Apu]

I had the problem in my Alfa (cammed, ECU, lightened flywheel, intake, exhaust, etc etc) - same problems in the other Alfas and a bunch other cammed Civics as well.

Only came across the problem when rolling downhill - usually down a spiral multi-storey carpark, engine idling, tapping brakes on the way down. After a few jabs, the brakes would feel wooden, and get progressively worse.

My guess was that at idle, I wasn't getting enough vacuum after a while, so we fitted a vacuum booster/canister on the line and that gave us a bit more bite.

I suppose we're less likely to experience that problem here...haven't come across a situation where you're just idling along and jabbing the brakes repeatedly. Don't really get gridlocked here too!

[Pokmx5]

Buy Graham Bells 'Four stroke performance tuning'.
It has a whole chapter on it. And for 30 bucks being able to make even 5hp more its great value. There are many other books also but this one I would recommend.

Dann

I got given this book today for FREE by an old man @ work who knows im tuning/playing around with my MX5...

[Pokmx5]

Between cams and headers?
LOL cams.

Well it dwpends really. Cams come in all sizes.
Unlike most mods, if you want more power you can just add bigger and bigger cams. This is at the expennse of low end power and a nice idle.

Having said that, some 440 dollar camtech regrinds will still get ,uch more of an increase on an otherwise stock engine than a full exhaust.

And they will run on a stock ecu.
And it will sound like a real car. Something a fart can and extractors cannot do.

Dann

DO you have an example of this sound by any chance ?

[plohl]

i bought bell's book for my thesis - amazon US ftw. End up using G.P Blair's design and simulation of 4 stroke engines a bit more though - bell's book is much much easier to read! definatly recommend it.

[pcmx5]

Hamster, have a look at my post and dyno sheets in that section of this forum.Pretty much what you are talking about,great drivability.

Peter.