TVIS+cams+Itb

[Rice86]

car - AE86
engine - 16v 4age bigport

im going with the T3+20v itb setup on my 16v bigport

have toda 264 7.9 and 272 7.9 cams and toda adj cam gears to suit

Questions.

Is it possible to keep TVIS with T3+20v itb setup?
is it worth keeping if possible?
are these cams direct bolt in without any other modifications needed?


EDIT, added question

What is best for this setup i am going with, Silver top ITB or Blacktop ITB?

[sundee]

Ditch the TVIS
Cams, 264 are a bolt in , 272 are not considered a bolt in, I would do valve springs if it were my engine

[timbo]

How are you going to run them, i.e. 272in 264out? 7.9 isn't much lift to do springs.

[meadan]

My cams have 7.9mm lift and Im running stock valve springs. Thats in a smallport though.

Im pretty sure the stock bigport cams have 7.9mm lift anyway? I think I read somewhere anything over 8mm lift is where you might want to worry about spitting out shims, Ill look for the link again.

[sundee]

So if you had 8.1mm lift you would do valve springs but not for 7.9mm
For the sake of a few hundred bux, you have 100% reliability .
In the end it's your engine, but for the cost of valve springs it's really a no brainer

[timbo]

Well I don't agree with that, it is like replacing something that doesn't need to and purely for the sake of it. Yeah, 8.1mm may need new springs and buckets, but if anyone was going for some serious cams I'm sure they would have AT LEAST 9mm of lift and a much bigger duration. You do what you need to, to make it work. I didn't replace my oil and water pumps during a rebuild because I pulled them apart and they were fine. I just think something like that is doing it for the sake of it, just because it is easy to do when the cams go in.

[sundee]

We seem to think very differently, I don't like to do things twice.

[meadan]

According to billzilla

Bigport has 7.56mm lift
Smallport has 7.1mm lift

[Rice86]

How are you going to run them, i.e. 272in 264out? 7.9 isn't much lift to do springs.

to be honest not to sure, but whatever way that will work the best to get performance with this setup. so someone that knows their shit can advise or the tuner should be able to advise what would be best anyways


According to billzilla

Bigport has 7.56mm lift
Smallport has 7.1mm lift

Cheers Adan! can i ask for a favor for help with the installation of the cams and ITB when the time comes? lol


So if you had 8.1mm lift you would do valve springs but not for 7.9mm
For the sake of a few hundred bux, you have 100% reliability .
In the end it's your engine, but for the cost of valve springs it's really a no brainer

i totally agree but in this case what works shall be left alone..and if it seems like springs are needed then springs will be bought no doubt.

ALSO i know you told me to ditch the TVIS, care to elaborate on reasons or anyone else?

i just don't want this to feel like a dog from 1000-4000rpm if you know what i mean. it still is going to be a very standardish bigport motor

[sundee]

Quote from billzilla's modified 4ag page:

Note that with cams larger than about the 260° mark you will actually benefit from removing the TVIS, if fitted. The TVIS, when used with cams smaller than about that duration, will give you more low end ( < 4,400rpm) power, but this effect disappears with the bigger cams.


Smart man, good enough for me.
And makes sence to, with the larger duration you have shifted the power band above the rpm range that the Tvis works in.
And if your going to make any decent power from an NA it needs large duration cams, and it's trade off for the extra top end is a loss of low/mid range torque.
There is actually no way around it.. Except force feed it.

[timbo]

We seem to think very differently, I don't like to do things twice.

No-one likes doing things twice, but some people do things once when it's not necessary at all, that was all I was saying.

[sundee]

Agree to an extent... ;)

[timbo]

Goodo!

[Rice86]

just another question

What is best for this setup i am going with, Silver top ITB or Blacktop ITB?

[timbo]

I think silvertop as that is what adaptor manifolds are suited to. SamQ will know more.

[meadan]

You can just match port the techno toy adapter to suit blacktop throttles. Silvertop throttles seem to be easier to find for cheap though...

[sundee]

T3 manifolds are made for silvertop quads... throttle selection should be made with future mods in mind .
if going black top quads the manifold can be easily match ported so there is no lip in the intake.
i doubt very much you could tell the difference between silver and black top quads if you put them on your motor now with the same spec. so in saying that if you can get some blacktop quads..... id just sort it all out now... but hay, we might be going back into another discussion now hay timbo ;)

[Rice86]

alright i think that covers all my questions i have for now, time to do tax return and get me ITB setup =D

[timbo]

T3 manifolds are made for silvertop quads... throttle selection should be made with future mods in mind .
if going black top quads the manifold can be easily match ported so there is no lip in the intake.
i doubt very much you could tell the difference between silver and black top quads if you put them on your motor now with the same spec. so in saying that if you can get some blacktop quads..... id just sort it all out now... but hay, we might be going back into another discussion now hay timbo ;)


Haha, yeah... quad choice is a good point though, has anyone tested both on a 16v?

[Rice86]

stated from another forum

silvertop quads vs blacktop quads
"The ST and BT have COMPLETELY different port structures. The ST is much more open, with no port division between the valves. This is great for VOLUME but not VELOCITY. The BT is a wider port, and has division between the valves. This creates more VELOCITY, but isn't as condusive to VOLUME."

[sundee]

I'll have a dig at translating...
Silvertop give more torque but become restrictive at a certain volume?
Blacktop give less restriction, so hi IT velocity can be achieved, to Be more efficient at higher rpm?

[timbo]

So lets say silvertop quads on smallport = win?

[Rice86]

Hmm.. So blacktop quads on bigport head because better Velocity from quads and bigport already has large ports to allow for more volume?

[sundee]

Yeah I think I'm with timbo..Someone else might like to comment

[Gunner]

Tyota were able to increase throttle diameter, in the BT because of better port structure. Where as in the ST the port design doesnt produce as much velocity as the BT, so using the smaller throttles better velocity can be achieved earlier in the inlet tract.

Think of a maccas straw and a kfc straw, blow through the maccas one and itll flow easier than the kfc straw at X pressure, but the velocity by the time the air reaches the end of the maccas straw the velocity is less than that of the kfc straw.

Basically lets assume, a std 16v head has a flow rate closer to that of the ST, theoritically, we can assume that the ST throttles will be bertter suited to the 16v heads, where the user wants to obtain closer to std drivability.

[Matt]

To be honest i think the difference in NA would be very minimal... Silvertop quads go for approx $200 where as blacktops are up at $350

The bench flow tests i saw between a smallport head and silvertop head were very similar...

Forced induction the blacktop head / quads wins all day everyday.

[sundee]

I think your last point is the key gunner, if the user wants to obtain close the standard drivability.
If your chasing big power from a 4a blacktop would be your choice, BUT, it would be nice to know at what point silvertop throttles are on their limit .

[Gunner]

To be honest i think the difference in NA would be very minimal... Silvertop quads go for approx $200 where as blacktops are up at $350

The bench flow tests i saw between a smallport head and silvertop head were very similar...

Forced induction the blacktop head / quads wins all day everyday.

Very few people would be able to pick it from driving, might see it on agraph though.

Im sure if you searched around joel, someone would have the cfm of both st amd bt throttles.

[Gunner]

And yes blacktop head is superior to st in every way imo eiher NA or charged.