7age options

totta crolla
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7age options

Postby totta crolla » Sun Jan 29, 2017 4:34 am

I'm considering putting together a 7age engine for a rally car, the increase in torque is welcome on 'blind' events when my navigator is reading from a map.
My cylinder head options are smallport, bigport or 20v the only stipulation is that I must use a single throttle body on a plenum. 20v blacktop head appears to flow better than anything else but I wonder if it is possible to modify a smallport inlet to fit ? Another reason I would like to use the 20v head is the vvt. So to summarise: 7age, smallport inlet, 20v head and vvt. Is it possible ? Would it likely be worth doing over a 7age smallport ?

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sirdeuce
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Re: 7age options

Postby sirdeuce » Sun Jan 29, 2017 9:53 am

OK, warning on using the 'T' word, you're gonna get a flogging. But from one that actually understands what you're saying.... Use the small port head and manifold. Keep the stock valve size, and do a good port clean up. If your budget can allow, Extrudehone the manifold. Keep the cam duration on the conservative side on duration and consider a cam with as much lift as the stock followers will allow, like a WEB camshaft 577 or 101. Anything bigger will move the torque peak too high in the RPMs. Watch out for naysayers on that, somehow peeps don't like anything less than the biggest cam they can cram under the covers. I have a set of cams that are really too big for what I want, not sure why I agreed to go with them. As far as the 20v head and adapting a manifold to it? There are manifolds out there for the 20v that have a single TB. Adapting the small port mani would more likely hurt the performance of the 20v head. Link with an example, this is for a turbo.

http://www.jspfab.com/catalog/i70.html

There are some out there for NA as well. BUT, not many consider building for low end torque peaks that carry flat through the RPMs. You might be able to talk to a fabber to have one built to your specs, but that would cost A LOT!
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sirdeuce
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Re: 7age options

Postby sirdeuce » Sun Jan 29, 2017 9:56 am

And if you're looking for a good bottom end I have a block and internals that would be awesome for what you're looking for here.
One shot, one kill.

totta crolla
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Re: 7age options

Postby totta crolla » Sun Jan 29, 2017 10:33 am

Thank you for a comprehensive reply. Keeping it smallport makes life so much easier for me and going from what you have said the short duration but high lift CatCams I already have may still be of some use.
I'm in the U.K so in the interest of shipping costs I would source the engine block here, can you tell me which rods and pistons you have and if you would consider splitting them ?

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sirdeuce
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Re: 7age options

Postby sirdeuce » Sun Jan 29, 2017 12:19 pm

Rods are Crower I-beam and the pistons are CP 81.5 flat top. rotating assy has been balanced with the flywheel. Really don't want to split the set though, it would be quite a waste.
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oldeskewltoy
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Re: 7age options

Postby oldeskewltoy » Sun Jan 29, 2017 3:28 pm

totta crolla wrote:Thank you for a comprehensive reply. Keeping it smallport makes life so much easier for me and going from what you have said the short duration but high lift CatCams I already have may still be of some use.
I'm in the U.K so in the interest of shipping costs I would source the engine block here, can you tell me which rods and pistons you have and if you would consider splitting them ?


interested...... Which Cat cams do you have??

transverse, or longitudinal application??

as to the head/intake combo... I would recommend a smallport with the smallport intake... but I'd add the O/S valves, and port it accordingly.... In fact I'm currently doing a O/S valve smallport head... this one for a 1.6. In your case... why I "argue" for an O/S valve... is it helps when you have the extra volume of 1.8 liters... Check on other 1.8 liter 4 valve heads and the valves they utilize.......
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

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totta crolla
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Re: 7age options

Postby totta crolla » Mon Jan 30, 2017 3:07 am

The engine is inline, AE86
I previously have run a smallport engine in 1600 configuration in this car.
These are the camshafts used and if I were completely honest I would say in 1600 form the bigport camshafts were better:
http://www.catcams.co.uk/acatalog/7105138.pdf

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Rogue-AE95
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Re: 7age options

Postby Rogue-AE95 » Wed Feb 01, 2017 8:31 pm

oldeskewltoy wrote:as to the head/intake combo... I would recommend a smallport with the smallport intake... but I'd add the O/S valves, and port it accordingly.... In fact I'm currently doing a O/S valve smallport head... this one for a 1.6. In your case... why I "argue" for an O/S valve... is it helps when you have the extra volume of 1.8 liters... Check on other 1.8 liter 4 valve heads and the valves they utilize.......


Thanks for posting this OST. I know it adds to the cost, but O/S valves are one more thing I will likely do with my 7A-G(T)E build that I've been delaying forever.

4A-GE intake (31mm?):
Image


Honda VTEC B series intake (33mm?):
Image


Honda left, 4A-GE right:
Image


4A-GE left, Honda right:
Image


I'm not sure which head the Honda valve came out of. Could be B16 or B18C1. It's not from a B18C5 (Type R), as its intake valves' "shafts" narrow down before reaching the "bases" of the valves.

Also I didn't check with calipers (yet), but the Honda valve "shaft" is slightly thinner than the 4A-GE valve.
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