Bluetop Bigport or Redtop Smallport?

[Hachiroku]

I'm looking at building a 4age for a ke70 and would like some opinions on which option would be best for me. It will mainly be a street car but I'd be keen to have a go on the track at some stage. I have done some sums and these both add up to be similar in terms of overall cost:

1. Standard rebuilt smallport, extractors, modded intake etc
2. Rebuilt bluetop, .040" (1mm) oversize high comp. pistons, Kelford 'street fighter' cams (maybe), extractors, intake...

Also, will the standard bigport ecu have any worries with the slightly modded engine? And would I need a custom head gasket to suit the bored out block?

[slighty_sykotic]

I'd go for a rebuilt retop... Hands down.


And why couldn't you get cams for the redtop? (just asking as its not in your post...)

Surly a redtop is not THAT more expensive than a bluetop (maybe $150? instead of $100?)

[Hachiroku]

I've been looking for a while and have found smallport motors tend to be harder to come by, as well as being dearer, especially complete ones with loom, ecu etc. The bits to rebuild them are dearer aswell. May not bother with cams at all until later on. I thought the bigport was also easier to set up for rwd?

If anyone in or near Christchurch has a smallport for sale I'd be keen to hear from you.

[crnkin]

smallport. smallport.

[sk1dlet]

smallport

[solitaire]

I love my smallport!

Kelford will regrind smallport cams for you...

[pc]

smallport

[Mr Revhead]

bluetop!!!


oh oops...... your after an engine not an anchor!
my bad

[gordon77]

bluetop!!!


oh oops...... your after an engine not an anchor!
my bad

hahaha mate that made my day a whole lot better but yeah - small ports are the shiz i wouldnt have thought bearings/rods/pistons are that much more than a bluetop

[Mr Revhead]

as far as parts prices go there is bugger all difference.

as far as finding a small port however...... they are out there, but blues would out number them 10-1!

[Santa'sBoostinSleigh]

buy my smallport!!!

[Hachiroku]

PM sent.

Are the smallport heads really that much better? How would the two motors compare if they both had the same compression ratio?

[gordon77]

the blue tops have a bit more 'pep' down low in the rev range due to tvis (which restricts it a little in the higher revs) where the small port doesnt have as much down low but when they get past 4-5k itl go like stink

[AE85coupe]

PM sent.

Are the smallport heads really that much better? How would the two motors compare if they both had the same compression ratio?

the bigport head just simply has overly big ports, a smallport head flows far better than a bigport.. (at least in NA applications and up to about 200hp) i can't remember the physics behind it, but i'm sure someone here will know

if your interested read this http://mototuneusa.com/think_fast_intake_porting.htm

[Dell'Orto]

the blue tops have a bit more 'pep' down low in the rev range due to tvis (which restricts it a little in the higher revs) where the small port doesnt have as much down low but when they get past 4-5k itl go like stink

Dunno, my old man's AE92 is a torquey little thing, as well as liking being revved.
I'd go with the smallport too if you're staying NA.

[gordon77]

the blue tops have a bit more 'pep' down low in the rev range due to tvis (which restricts it a little in the higher revs) where the small port doesnt have as much down low but when they get past 4-5k itl go like stink

Dunno, my old man's AE92 is a torquey little thing, as well as liking being revved.
I'd go with the smallport too if you're staying NA.

AE92's come out with tvis to dont they?

[crnkin]

the blue tops have a bit more 'pep' down low in the rev range due to tvis (which restricts it a little in the higher revs) where the small port doesnt have as much down low but when they get past 4-5k itl go like stink

bullshit

[pc]

the blue tops have a bit more 'pep' down low in the rev range due to tvis (which restricts it a little in the higher revs) where the small port doesnt have as much down low but when they get past 4-5k itl go like stink

I'm reasonably sure that's incorrect.

[malc]

Is there any advantages that the bigport has over the smallport?
or which is better for a mid to highly tuned 4age?
not sure if its right, but I did see somewhere that the bigport could be better in a highly tuned state because it can flow more air (no idea if its true or not).

[Truenotch]

AE92's come out with tvis to dont they?

Ae92's came out with both, They were smallport from 1990 - 1991 and were Largeport redtop after that (TVIS red/black top or whatever you want to call it).

Smallport heads are a better flowing head so they are better all the time, whether it be in a mild tune or a High tuned state. Most people choosing to make a fast 16v use smallports they are better all round engines...