Building a 4AG Hammering out details.

[DeftAnesthetik]

hello again to all, just have a few q's to help me get this moving.

where I am at.

I have a ST block with oil squiters as well as ST crank. Have purchased a set of Spool rods and 8.9cr GZE pistons. Large port head, (port and polished) HKS 264 cams (in and ex) all new seals, gaskets and ARP where i can (of course) microtech ecu on its way. ST quad throttles. I still have to pick my turbo and manifold, I am on the fence to go for a t3 or a t28, I want something big enough to puff out over 200hp. (i am sure either will do)

EDIT: Actually Have 1x256 8.35mm cam and 1x 264 8.35mm Cam

what i need to know

My main question is about valves.... is it worth oversizing them? I have been using the net for research but on one site i here that the bigport valves are already too big and on another site i read that they are too small.... so much conflicting information.
I will be installing aftermarket valve springs and will also be doing the 1sz lifter/bucket conversion.

next q is about the oil pump..... why are there so many different drive gears for these???? I have 3 or 4 sitting in my pile of parts and every single one has different gears. Do any of the gear sets perform better than the other? is one more reliable then the other? does it make any difference at all?

lastly(for now) I have taken a c56 from a ST and modified it to work in my MR2. when should i start to worry about this not being able to handle power? I know its a different tranny and axles etc. for the factory supercharged aw11's but this transmission is newer than the S/C and the c50(2) that i removed.

thanks in advance. im sure i will start being annoying soon as the last of my parts(except turbo stuff and ecu) have shown up here. and now i get to start building.
I should start posting my progress on the car soon so for those interested keep an eye out on my MR2 thread.

EDIT: might need to ask about staggered cams as well... i will do my own research first.

[Ben Wilson]

The bigport ports are too big, the valves are OK. On a motor built to the specs yours is going to be, big valves should be a good thing.

[DeftAnesthetik]

The bigport ports are too big,

thats my reasoning for forced induction

On a motor built to the specs yours is going to be, big valves should be a good thing.

so should i fit oversize or just leave em and spend my money elsewhere (looking at ferrea@~$20 a piece)

[abently]

thats my reasoning for forced induction




so should i fit oversize or just leave em and spend my money elsewhere (looking at ferrea@~$20 a piece)

Which is correct, FI will negate the effects of the ports being too big, but this is with respect to density (ie Boost) so select a Turbo which still runs within its efficiency island @ 30psi, or just the higher of the two Turbo's your going to choose from.

Is the Bigport exhaust valve suitable for FI ? That's the only reason I would recommend going Ferrea etc. You won't see gains in FI unless your re-modeling the ports to suit.

Are the Factory Oil gears all straight cut, all helical or a some of both depending on the year ? Are they all machined or cast gears ? If they flow different rates, then their may have been revisions made the Block throughout production to adjust Oil pressure at various points. In which case I wouldn't recommend mixing them if you can avoid it ?

Transmissions are designed around Torque. If the C56 was designed to handle the same torque as the C50 from Factory, then it would be reasonable to expect similar max-power limitations.

[roadsailing]

leave them, you will get 200hp with standard cams turbo, valves arent going to be a problem.

what i think Ben means is that you will get better off boost ersponse from smallport heads, if that doesnt bother you then bigport heads will be fine.

i'd stick with t25 flange instead of T3, plenty of choice for turbos and worst case you can pick them up cheap if you need a replacement.

[Ben Wilson]

My access is blocked from work, but have a look on www.performanceforums.com there is a thread there covering the difference porting and valves make to a turbo motor.

[Ben Wilson]

Here is the thread I was talking about earlier.

So you don't have to join up to see the results, This is the dyno sheet showing before and after big valves/porting.



Check out how much earlier it comes on boost!

[30psi 4agte]

For the valves ...Its up to you..

200hp .at the wheels is a walk in the park for a turbo 4a. You will have no prob making this hp on std valves..

FWIW you can make 283rwkw with std valves and cams

I would be more inclined to go to the t3 style flange as it gives you more option for turbo choice down the track should you feel the need to up the ante........ but again it is up to you.

Just to contradict myself ... Those t28 style turbos like the hks 2530 etc are bloody great little things ! They can provide awesome response but provide the topend to go with it.

It sounds like you have the right bits here and a decent 4agte will come from it! 200hp is aiming a little low for the combo you are putting together ??

[oldcorollas]

Which is correct, FI will negate the effects of the ports being too big, but this is with respect to density (ie Boost) so select a Turbo which still runs within its efficiency island @ 30psi, or just the higher of the two Turbo's your going to choose from.

Is the Bigport exhaust valve suitable for FI ? That's the only reason I would recommend going Ferrea etc. You won't see gains in FI unless your re-modeling the ports to suit.

Are the Factory Oil gears all straight cut, all helical or a some of both depending on the year ? Are they all machined or cast gears ? If they flow different rates, then their may have been revisions made the Block throughout production to adjust Oil pressure at various points. In which case I wouldn't recommend mixing them if you can avoid it ?

FI may somewhat negate losses from having poor port velocity, but it will still be behind a port with better velocity ... ie, until you get to stupid power, a small port will be better almost everywhere...

how will you nto see gains going to forced induction if you leave the ports alone? or did you mean valves?

perhaps you should look at some oil pumps.. even seen a helical cut oil pump?
mixing parts of oil pumps? wtf? dude, seriously.. go and look at a 4A oil pump, you will quickly understand... i hope..

from the little research i did before , the pump to get was the 15100-19036 part number
i believe this is the late model AE92, and has been listed around for the 101 as well. it was also listed to supercede the earlier model pumps
edit: i have one here and can take pics of the gears if you want to compare..

there is a TRD pump ger set, but they fetch up to $1K on yahoo. the difference is the gears are machined from steel, and not from cast or sintered parts.

[Ben Wilson]

FWIW you can make 283rwkw with std valves and cams

The big valves and porting don't seem to make that much difference to top end, it's the midrange where they shine. By bringing the motor on boost that much earlier, you wind up with a much faster car in the real world.

[abently]

perhaps you should look at some oil pumps.. even seen a helical cut oil pump?
mixing parts of oil pumps? wtf? dude, seriously.. go and look at a 4A oil pump, you will quickly understand... i hope..

Just to clarify, many Engines allow to you swap over/interchange Oil pumps from various years of similar blocks. I'ld advise you to just use the one which was designed for your particular Block. That is all.

[abently]

The big valves and porting don't seem to make that much difference to top end, it's the midrange where they shine. By bringing the motor on boost that much earlier, you wind up with a much faster car in the real world.

Those graphs read like an Exhaust side which has been choked by too much flow.

Big valves are fine if you are going to overbore the Engine 1-1.5mm.

You can get similar results to what Porting & Valves achieve with harsher camshafts and a small Turbine Housing. Co-incidentally its cheaper as well.

[oldeskewltoy]

Remember.... to properly benefit from O/S valves you need to open up the ports immediately behind the valves to get the benefit. You also would need new valve seats to properly maximize the O/S valves. All that is added cost. And as 30psi 4agts stated he is making in excess of 280 kw at the wheels.

For oiling.... - http://www.billzilla.org/4agstock3.htm

[oldcorollas]

Just to clarify, many Engines allow to you swap over/interchange Oil pumps from various years of similar blocks. I'ld advise you to just use the one which was designed for your particular Block. That is all.

i can't use a 3T oil pump in a 4A? thanks for that, you've just saved me dacades of pain and heartache

ps, please send me a picture of an oil pump with helical teeth

pps, here are some oil pump pictures for you
http://www.billzilla.org/pumptroch.gif
http://www.billzilla.org/pumpcrs.gif
http://www.billzilla.org/pumpgear.gif

and here are the gears of a 4A pumpfor your future reference
http://opc.mr2oc.com/online_parts_ca...oil%20pump.GIF

http://blog32.fc2.com/m/muzanlevin/file/oil_pump_01.jpg (hot link broken )

[Mr Revhead]

whan talking about the 4age
small port and bigport are relative terms....
the smallport still has big ports!
you need to be fairly serious for them to be too small
even with a turbo.

200hp is easy on a 4age (FI that is!)
so i really wouldnt waste time and $$$ on bigger valves etc unless your after the last few percentages.

as for the oil pumps.....
oldcorollas is correct, the pump is the same for ae92 4age/ze and the ae101 4agze.
they supercede to the same one. i even have a sneaky suspicion the silvertop one is the same too....