head modification

[88*mr2]

ok so as soon as i finish my rusty body i plan to to a cold air intake and a new exaust system...after that i want to do some head modification work (im working with a redtop)

so i would like to get bigger valves and have it ported and maybe have the chambers polished...?

ok so before i do all this i need to get my fuel system up to par. would it be eaiser to do a FPR or bigger injectors? depending on which route i go wat will i need to do with the ecu?

thanks for the advice and suggestions guys!

oh and plz dont mention NOS (it tends to make the convo stray lol)

[Papo J]

For an NA car leave the fuel system alone even with head work, it already runs richer than it needs to at anything past 1/2 throttle. But if you think you need some kind of control an adjustable FPR is a good starting point.

[Jackstand Queen]

Bigger valves probably requires a fuel upgrade (FPR rising rate job), or larger injectors. I have a set of 440cc Supra laying around somewhere.

I would think that if your mods keep the engine under 200 potential HP, that your oem ECU can handle it.

But if you added an oversized main pulley, or a larger SC, you'd probably need a stand-alone EMS.

You're in the forced induction forum, so I assume you have an SC. I'd steer away from a so called "cold air intake system". Having a an air intake inside the engine bay is actually a hot air intake system. And intake air temperature is a critical in boosted engines. Hot intake air = engine go boom boom.

[te51levin]

If you say "redtop", I assume that means smallport, with no TVIS. If that's the case, you will need the smallport ECU to run it properly. If your car has the stock '88 bigport, just say "bigport" instead; the term "redtop" is really worse than useless, because it confuses people about what you are working with.

If you're still on the bigport, look into a smallport swap. They are better in several ways and will give you more to start with, and higher potential for a modified street engine.

Your fuel system is just fine. Larger injectors are not necessary if a ported or tweaked cylinder head is your only modification.

Bigger valves are nice, but unless you've modified many other things, the stock valves are probably not a restriction, and not the best place to spend your money. If I was in your shoes, I'd have the head built by a reputable local machine shop. If you can find one that specializes in performance work AND has a strong reputation with the import crowd, you're golden. Have the shop do a good five-angle valve job. Three-angle comes stock, so don't let them tell you it's an upgrade. Have them tidy up the bowls and guides, and clean up the ports a little, smoothing off the sharp edges along the walls and floor of the ports. Do not enlarge the ports at the manifold face; that does no good whatsoever.

Mild cams are also very useful. Something like Web #294 (that's the grind number, not the number of degrees) or #577, which is what I use, will work with the stock ECU if you tune the cam gears appropriately. Adjustable cam gears and dyno tuning absolutely will be required to get the best out of any modified combination.

Do some reading, spend some time learning, before buying anything or making decisions. The Honda boys "catalog method" is useless, so avoid getting caught up in underdrive pulleys, oversized throttle bodies, goofball spark plug wires, etc.

You're posting in the "forced induction" forum - that means supercharged, turbocharged, etc. Are you planning on adding any of those?

[88*mr2]

its an n/a...and yea its a smallport with tvis. so if i do a 5 angle job will i need to change valves or would stock work? and so do u think i should just leave the ports alone and do the 5 angle valve job and leave valve sizes the same? have the head cleaned up a bit? if i put mild cams in it wat other modification would come alnog with doing that besides adjustable came gears? wat about polishing the chambers (i have heard good and bad about that so i dont really know) and i dont know if im going to turbo or not i havent planned on it but it could happen some day

[te51levin]

Originally Posted by 88*mr2

its an n/a...

Then you should be posting here: NA - 4A-GE/3A-LU - Toyota MR2 Message Board

Originally Posted by 88*mr2

and yea its a smallport with tvis.

No, it isn't. If you have TVIS, you have a bigport. If you have a smallport, you do not have TVIS.

Originally Posted by 88*mr2

so if i do a 5 angle job will i need to change valves or would stock work?

Stock valves will work fine for your application.

Originally Posted by 88*mr2

and so do u think i should just leave the ports alone and do the 5 angle valve job and leave valve sizes the same?

Yes, that's exactly what I said.

Originally Posted by 88*mr2

have the head cleaned up a bit?

Again, that is what I suggested.

Originally Posted by 88*mr2

if i put mild cams in it wat other modification would come alnog with doing that besides adjustable came gears?

If they are reasonably mild, the adjustable gears (and the proper cam timing using those gears) are the only mod you'll need to support them.

Originally Posted by 88*mr2

wat about polishing the chambers (i have heard good and bad about that so i dont really know)

Yes, that's fine, though on most engines it is not a terribly good use of time. if you're paying someone to do it, it's not a terribly effective way to spend your money.

Originally Posted by 88*mr2

and i dont know if im going to turbo or not i havent planned on it but it could happen some day

It sounds like you're just now getting involved with your car, so let's not plan on that stuff just yet. By the time you're ready to pull that off you'll be answering questions based on your own experience, not asking them.

Keep this in mind, too: The internet is full of information. Much of it is incorrect. People who offer you their advice don't always know what they're talking about. Use your head and read some books before making any decisions.

[88*mr2]

Originally Posted by te51levin

Then you should be posting here: NA - 4A-GE/3A-LU - Toyota MR2 Message Board


No, it isn't. If you have TVIS, you have a bigport. If you have a smallport, you do not have TVIS.


Stock valves will work fine for your application.


Yes, that's exactly what I said.


Again, that is what I suggested.


If they are reasonably mild, the adjustable gears (and the proper cam timing using those gears) are the only mod you'll need to support them.


Yes, that's fine, though on most engines it is not a terribly good use of time. if you're paying someone to do it, it's not a terribly effective way to spend your money.


It sounds like you're just now getting involved with your car, so let's not plan on that stuff just yet. By the time you're ready to pull that off you'll be answering questions based on your own experience, not asking them.

Keep this in mind, too: The internet is full of information. Much of it is incorrect. People who offer you their advice don't always know what they're talking about. Use your head and read some books before making any decisions.

thanks for the help advice and constructive critisim ...yea im just starting out with this mr2 thanks
and yea on that last part about ppl not knowing what there talking about i was told it was a small port when i gave them the information they asked for to help me ID my engin...thanks

[scottohno]

yeah dont feel bad though, when i bought mine the people said it had a "corolla engine" in it... like that means anything. it appears to be the stock engine, the very old old old version of the 4age, but i do suppose you could probably put redtop covers on my engine and make it a redtop, or you can put the stock covers on and make it look stock... or m i wrong?

[toyotaspeed90]

Originally Posted by scottohno

yeah dont feel bad though, when i bought mine the people said it had a "corolla engine" in it... like that means anything. it appears to be the stock engine, the very old old old version of the 4age, but i do suppose you could probably put redtop covers on my engine and make it a redtop, or you can put the stock covers on and make it look stock... or m i wrong?

they were probably just referring to parts availability....

valve cover colors really don't mean anything on these engines anymore....

first gen 4age's are 3 rib blocks... they have the smaller internals (18mm wrist pin and 40mm rod journal), they have t-vis (stock manifolds have 8 runners).

2nd gen 4age's are 7 rib blocks.... they have t-vis (same stock manifold... with the exception of the EGR location change in 88, but an early manifold will still work on it), but have the larger internals (20mm wrist pin and 42mm rod journal).

3rd gen 4age's are 7 rib blocks... they do NOT have t-vis (4 intake runners)... they also have an oil drain on the intake side of the head at the end of #4, their internals are the same size, but beefier than the 2nd gen 4age

Now the tricky part..... all heads will bolt onto all blocks.... you can swap internals as long as the sizes match.... this includes gze's