Port / Polish
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i was about to start before i sold my EGT..
port the exhaust side of the head as big as i could go then port match the exhaust manifold to it.. it boggles my mind how much the 1.8's love the free-flowing exhaust. most engines like a little backpressure, my 1.8 ran it's best when it was a straight header with no exhaust at all.
does anyone sell larger butterflies for the secondaries on the intake? Porting the primaries is pointless since it will give you a loss in torque, and add nothing top-end.
and no - no kit i could reccomend - everything i've ported on my tbird was with a regular carbide grinding bit from lowes.
port the exhaust side of the head as big as i could go then port match the exhaust manifold to it.. it boggles my mind how much the 1.8's love the free-flowing exhaust. most engines like a little backpressure, my 1.8 ran it's best when it was a straight header with no exhaust at all.
does anyone sell larger butterflies for the secondaries on the intake? Porting the primaries is pointless since it will give you a loss in torque, and add nothing top-end.
and no - no kit i could reccomend - everything i've ported on my tbird was with a regular carbide grinding bit from lowes.
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a Dremal (?spelling?) works magik. Just take it slow.
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so you recomend not to port and polish a 1.9?????????? :?:
Why ?
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Why ?
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Seriously...how many people build 1.9s for power? it's almost pointless to start with 88hp and port and polish to gain 2-3 hp. combine it with sohc and 8 valves, and all you have is a car that breathes a little better with 92 hp.onelatin8ball said:so you recomend not to port and polish a 1.9?????????? :?:
Why ?
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I'm sure there's someone out there that makes butterflies in any size you want...just port and polish, measure and get the right size b/f valve. You could probably do the same thing with the TB as well...TitoElSpicco said:
You're making me wanna call around to shops/manufacturers and find some so I can try it on Primer Guru's GT (my legendary(???) Escort).
Uhhh.... well?egtdude said:well I say to the right person you can find a way to do it with a 1.9. Its designed isn't as well suited but I like a challange
I have a little secret quick 40 HP trick I've been wanting to trying out... wish I had access to a 1.9
You're so mean, teasing us like this...
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Dremel will be a PAIN IN THE ASS and take years... You're going to need an air die grinder if you plan on doing anything serious.
As far as the throttle body, i forget what engine it was, but i THINK it was mazda's popular 2.5 v6 that looked larger but very similar. Would probably work.. if not an RX-7 tb?
Check around mang. I'd love to know. The little butterflies are probably the biggest bottleneck to a 200hp n/a 1.8.James92Scort said:I'm sure there's someone out there that makes butterflies in any size you want...just port and polish, measure and get the right size b/f valve. You could probably do the same thing with the TB as well...
You're making me wanna call around to shops/manufacturers and find some so I can try it on Primer Guru's GT (my legendary(???) Escort).
As far as the throttle body, i forget what engine it was, but i THINK it was mazda's popular 2.5 v6 that looked larger but very similar. Would probably work.. if not an RX-7 tb?
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i'd recommend going to a junkyard and ripping off and intake.egtdude said:
::begins search for picture::
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LMAO Dreamland...hahahahha
Anyway.....I found the pictures. They're crappy cause I didn't have my digi cam when I took them. but they show the butterfly valves.
http://www.cardomain.com/id/james92scort
scroll down to the bottom of the page. :wink:
Anyway.....I found the pictures. They're crappy cause I didn't have my digi cam when I took them. but they show the butterfly valves.
http://www.cardomain.com/id/james92scort
scroll down to the bottom of the page. :wink:
The exhaust side can be done as smooth and shiny as you like. Its the intake side you need to be careful with. You can port match the intake runners, but dont get them smooth; you'll want them finely pitted. Also, dont match the bottom of the runner with the intake port on the head. There should be a small lip present if its done right. Also, a small lip on the bottom, trailing edge of the exhaust port can help get gasses out of the chamber faster, but only flow testing will show what needs to be done. Velocities are as important as volume. At any rate, just cleaning it up with a tool yourself wont do much good unless you flow test the whole oufit. Thats really the only way to tell where and how much metal needs to come off. A good shop can flow test the head for you and determine the best scenario to clean up the intake and exhaust restrictions for best performance, but it isnt cheap. Doing it yourself, most likely, will either give you minimal to no gain at all or even cause a decrease in performance because just blindly removing restrictions severely alters the rate of flow into and out of the head. It isnt about getting as much into or out of the head as possible, the key is keeping the correct ratio of intake to exhaust flow through the head.
Ask an automotive machine shop what they charge and make a decision based on that.
My car was done professionally and the only gains I obtained were in the top end. WAYYYYYY up in the top end, mind you. Now, with some more engine mods and forced induction those gains would increase exponentially, but on a basically stock engine the gains were minimal, barely noticeable and quite expensive for what I got out of it. I did the head and intake work based on future plans for turbocharging, but that jusut hasnt happened yet. Maybe soon. Good luck!
Ask an automotive machine shop what they charge and make a decision based on that.
My car was done professionally and the only gains I obtained were in the top end. WAYYYYYY up in the top end, mind you. Now, with some more engine mods and forced induction those gains would increase exponentially, but on a basically stock engine the gains were minimal, barely noticeable and quite expensive for what I got out of it. I did the head and intake work based on future plans for turbocharging, but that jusut hasnt happened yet. Maybe soon. Good luck!
The exhaust side can be done as smooth and shiny as you like. Its the intake side you need to be careful with. You can port match the intake runners, but dont get them smooth; you'll want them finely pitted. Also, dont match the bottom of the runner with the intake port on the head. There should be a small lip present if its done right. Also, a small lip on the bottom, trailing edge of the exhaust port can help get gasses out of the chamber faster, but only flow testing will show what needs to be done. Velocities are as important as volume. At any rate, just cleaning it up with a tool yourself wont do much good unless you flow test the whole oufit. Thats really the only way to tell where and how much metal needs to come off. A good shop can flow test the head for you and determine the best scenario to clean up the intake and exhaust restrictions for best performance, but it isnt cheap. Doing it yourself, most likely, will either give you minimal to no gain at all or even cause a decrease in performance because just blindly removing restrictions severely alters the rate of flow into and out of the head. It isnt about getting as much into or out of the head as possible, the key is keeping the correct ratio of intake to exhaust flow through the head.
Ask an automotive machine shop what they charge and make a decision based on that.
My car was done professionally and the only gains I obtained were in the top end. WAYYYYYY up in the top end, mind you. Now, with some more engine mods and forced induction those gains would increase exponentially, but on a basically stock engine the gains were minimal, barely noticeable and quite expensive for what I got out of it. I did the head and intake work based on future plans for turbocharging, but that jusut hasnt happened yet. Maybe soon. Good luck!
Ask an automotive machine shop what they charge and make a decision based on that.
My car was done professionally and the only gains I obtained were in the top end. WAYYYYYY up in the top end, mind you. Now, with some more engine mods and forced induction those gains would increase exponentially, but on a basically stock engine the gains were minimal, barely noticeable and quite expensive for what I got out of it. I did the head and intake work based on future plans for turbocharging, but that jusut hasnt happened yet. Maybe soon. Good luck!
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that's intake tubing. theoretically, there shouldn't be any gas or oxygen left in the air before it reaches the exhaust side.
The theory on not polishing your primary (longer) intake runners is due to fuel condensation on the walls on the intake plenum. With a smooth surface, fuel is more likely to come out of atomization (from the air/gas charge) and stick to the walls. On the secondary runners (the butterfly jobs), it's a more direct shot at the valves so polishing here isn't likely to cause any harm. This is a concern on the SVT Contour/Taurus SHO engines.
However, if you look at the 1.8 intake, you'll see that the fuel injectors squirt their load directly before the entering the head. So polishing either primary or secondary intakes on a GT engine isn't going to alter the charge mixture.
However, if you look at the 1.8 intake, you'll see that the fuel injectors squirt their load directly before the entering the head. So polishing either primary or secondary intakes on a GT engine isn't going to alter the charge mixture.
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