benifets of 20v head over 16v head turbo'd

[Poggy]

It's a GT28.

Same thing.

[30psi 4agte]

Same thing.

Same thing as what ?

[skiddz]

as a t28 i would assume. GT28=T28=T28G depending on which school you come from, i know all the p00sar people call them T28G's, in the end its all just a sizing code

while the 20v head may only flow 2hp more than a 7afe head, there are other benefits, like independant cams (not scissor driven) and vvt

[Poggy]

as a t28 i would assume. GT28=T28=T28G depending on which school you come from, i know all the p00sar people call them T28G's, in the end its all just a sizing code

while the 20v head may only flow 2hp more than a 7afe head, there are other benefits, like independant cams (not scissor driven) and vvt

Yeh i wrote about the VVT very good for a nice power curve

[oldcorollas]

as a t28 i would assume. GT28=T28=T28G depending on which school you come from, i know all the p00sar people call them T28G's, in the end its all just a sizing code

while the 20v head may only flow 2hp more than a 7afe head, there are other benefits, like independant cams (not scissor driven) and vvt

"GT" is new generation of turbo with different aerodynamics for the impellers.
so T28 and GT28 are quite different beasts.

isn't a GT25 similar in potential to a T28? and GT28 bigger again? (the sizing code still works for the flanges no?)

[30psi 4agte]

"GT" is new generation of turbo with different aerodynamics for the impellers.
so T28 and GT28 are quite different beasts.

isn't a GT25 similar in potential to a T28? and GT28 bigger again? (the sizing code still works for the flanges no?)

I was leading to this !!


I sent pro16t a pm a couple days ago to explain this to him. Prob should have put it on here They are quite different indeed.

Alot of the younger blokes of today call them the t28 cos they basicly know them as that ....and were still sucklin mama's teet when the OG T28's were kickn.. They are led to believe that the t28 is off of the sr 20 etc etc. But infact the the real T28 (not the GT28) turbos have been around for many years and are unused in todays hi-tech turbo world....and have been sort of superseeded by the now imfamous GT versions.

Back in the day people would pull off their T28 to fit a larger T3 frame turbo with a better flow potential.

The T28 has a flow potential of around 280-300 Lb per min which = around 300 hp at the fly. A GT28 will flow anywhere from 330 - 400 Lb per min = 350-400 hp at the fly.
Depending on its configuration / wheels / AR etc

As far as the flange fit goes... as far as im aware they are still the same. Although there are various models getting around now with the t3 flange.

[gixer]

I think this debate will be never ending 20v vs 16v, just use what you can get hold of and be happy.

[oldcorollas]

I think this speculation will be never ending 20v vs 16v,

until someone takes the same setup, and only changes the head... just flowbenching is not enough, just peak power figures is not enough....

but really, who would bother to do that?

[30psi 4agte]

Ill do it when i win xlotto and have all day to play like a school boy

[Talasas]

While there's no bottom line to this one point people need to see is that all the heads work. Use what you have and quit whinging about what's better

[fixeruperer]

no 2 of a kind engines are ever the same.
20v is good for n/a due to higher air velocity and with that extra valve accepting it, 16v is better for boosted application due to bigger ports allowing for a shit load of air to pass threw it.

[Mr Revhead]

ok, havnt read the entire thread in detail as i dont have time....
but i want to point out....
GZE rods are the same as NA rods of the same year.... the only difference is the pistons.


as for the heads.... i reckon the 20v head is better, and the silvertop one the best of the 2 to start with. it has a better combustion chamber and as the ports are smaller on the exhaust side you have more to work with.

however i dont think any of that really matters with most applications
300hp can be done no problem with any 4age head, so if you have one. use that.

[Sam_Q]

with the combustion chamber change I still dont understand why they did it, surely they must of had a reason? I would like to see a power run on a silvertop that has been fully ported then have the head swapped over to a black and a thinner gasket run (to keep the compression ratio the same) and then given another power run. Combustion chamber or not I think the black would come out in front, I beleive you cant make the ports on a silver as good no matter how much you port i, if you add some material somehow then maybe.

also I agree with revhead, any 4age engine can handle good power when boosted so it doesnt matter much for a normal person

[Mr Revhead]

we recently sent both heads off to a respected race engine builder
he flowed both, and sent the blacktop one back an dis working on the silvertop one
hes reasons, the combustion chamber is better, and he can make the ports as good or beter than the stock blacktop ones.
its not the first head expert iv had say that

[roadsailing]

just remember that flow does nto equal power! it comes down to combustion chamber design (squish areas etc) leading to detonation resistance and lots of other things.

remeber, toyota only made 2 variants (of one engine) with 5 valves per cylinder, that must tell you something