hey guys I just wanted to discuss more the option of building a FE head for peformance as I think it has a superior port design to a 4age.

Edited November 7, 200817 yr by Sam_Q

why can't it be bored out to 81mm?

 

machq- That F head if what i think it is has a better port design than any 4age

Just waiting for someone to build one optimised for performance. How's yours going?

Just waiting for someone to build one optimised for performance. How's yours going?

 

well theres this one that I shamelessly nicked off billzillas page:

 

 

other than that there was one built for a custom by road and track that was reported to have produced 200hp, this was told to me by Terry-O when I called him.

 

 

as for my "build" its stuck, I don't want to pay $980 for a local weld and grind for a set of cams that might be the wrong profile. I am right now looking into getting 4age valves shortened and modified to suit the exhaust side so that it holds the bucket higher up and something custom for the inatke, this would then in theory let me grind off the base circle diameter and have some meat to grind off the cam. The base circle is a very large diamater on the 4/7afe cams so theres stacks of meat if I can get away with having a raised bucket.

 

As for the 6a bore, I think someone needs to shine a torch down the cooling channel and see how much meat is in there. I mean I don't know much about engine/block construction but I would of thought that this block would of come out of a simular mould to that of a 4a and hence would just have extra material in the bore walls. I know this is the case for 2 to 3T engines.

machq- That F head if what i think it is has a better port design than any 4age

 

A lot of people say that but has any one got flow figures to back it up? Would be interesting. :)

Edited November 6, 200817 yr by Jason

A lot of people say that but has any one got flow figures to back it up? Would be interesting. :)

 

A flowbench gives part of the story only, if it was just the CFM then a 20v would blow everything away, the race track is a different thing. Also although the port design is tottaly superior I have to admit it takes a lot of work to enlarge the ports to whats needed to compete. I don't know for sure but I think I removed about 4 cups of aluminium filings and spend about 40 hours die grinding maybe?

oh and I forgot to mention the 6A has a superior valve angle for top and bottom end power, there that should stir someone up!

I no flow benching is 'ideal' scenario but would still seem like start to comparative testing? I assume since you are porting you will be getting it flowed?

 

Not being a dick (well maybe i am i don't give a f) but until i see some hard evidence I'm staying totally neutral.

Edited November 7, 200817 yr by Jason

no I quite like your open minded untill proven otherwsie attitude. I will only be getting it flow benched to equalise the port flows and not much else. However I do know the choke points of each port so I could in theory work out how efficient the ports are to a point from that.

How you did you find the choke points? Best thing i ever did was shove a hose through the intake to see how it flows. Nothing ever flows the way i expect. :)

How you did you find the choke points? Best thing i ever did was shove a hose through the intake to see how it flows. Nothing ever flows the way i expect. :)

 

good question Jason, for my porting to tune the intake runners to have the right airspeed at the RPM at which I wanted I needed to significantly increase the inside diameter of the ports. Because they are a long tubular shape I was able to do this quite accurately with a set of inside dividers. So by me knowing the diameter of the ports just before the valve guide/bowl area which is the choke point I can just work out the area for one and double it (for the combined intake port area). From what I read knowing the measured air-speed on a flowbench for a given choke point is the best indication of the ports efficiency.

 

But hey don't mistake me for a professional I am just doing my best to piece together the info I need from all sources, I could of just made a total fool of myself by what i just said.

 

-Sam

The other thing you have to worry about if increasing bucket height is the lash area of the cam on the shim. Tighe cam's reckoned they'd be able to maximise lift and duration to not require a shim under bucket conversion when I asked a similar question, but the smaller the base circle, the steeper the cam profile. The force when opening the valve isn't applied as evenly on the top of the bucket, but more to the outer edge. This makes the motor more likely to spit a shim at high RPM and total your cams and possibly the whole head. Might be worth shim under bucket depending how big you're planning to go cam wise.

 

well theres this one that I shamelessly nicked off billzillas page:

 

other than that there was one built for a custom by road and track that was reported to have produced 200hp, this was told to me by Terry-O when I called him.

 

 

as for my "build" its stuck, I don't want to pay $980 for a local weld and grind for a set of cams that might be the wrong profile. I am right now looking into getting 4age valves shortened and modified to suit the exhaust side so that it holds the bucket higher up and something custom for the intake, this would then in theory let me grind off the base circle diameter and have some meat to grind off the cam. The base circle is a very large diamater on the 4/7afe cams so theres stacks of meat if I can get away with having a raised bucket.

 

As for the 6a bore, I think someone needs to shine a torch down the cooling channel and see how much meat is in there. I mean I don't know much about engine/block construction but I would of thought that this block would of come out of a simular mould to that of a 4a and hence would just have extra material in the bore walls. I know this is the case for 2 to 3T engines.

yeah I thought about this but because the buckets on these heads so big I am pretty sure even the shims are bigger than the total bucket size of a 4age. I just thought if the 4age engines can run 10mm lift with the same diameter then I should be able to.

Good discussion. :)

 

But it is rather off-topic from the original post, so if you guys want to give it a name, I'll split it.

 

Cheers :)

ok good idea, how about FE head for perfomance

Sweet, bigger buckets on the 4AFE ... sounds like it could be toyota's secret weapon after all. Yeah, I hope it works out Sam, I want to do the same thing to a 5SFE head. Untested waters are a little scary though, it can really bite you on the ass if you don't count for every possibility.

 

yeah I thought about this but because the buckets on these heads so big I am pretty sure even the shims are bigger than the total bucket size of a 4age. I just thought if the 4age engines can run 10mm lift with the same diameter then I should be able to.

 

Sorry dwarf, only just saw your post :)

Edited November 7, 200817 yr by beerhead