300RWKW 4AGTE Turbocharger Selection

[trdee]

watchu on about OC? I'm not talking about the gains to do with E85, thats a whole 'nother topic. Just replying to 30psi 4AGTEs post earlier in the thread saying the BT head doesnt make gains over the 16v head. The 60fwkw increase was with both the 16v head and BT head running on petrol, it picked up ANOTHER 50fwkw going from petrol to E85 after the fact, plus one more pound of boost

And even if it didnt outflow a 16V head, VVT is hella useful for increasing the area under the curve and decreasing turbo lag etc etc. Plus my pistons for the stroker kit have already been made with 20v flycuts so there's no going back now unless I wanna buy another set of pistons.....

[oldcorollas]

just thinking out loud about 273kw at 18psi on 1.6L... (100Nm/L/bar, 8000rpm.. no losses at that boost = doable?)

have reliable info that BT head makes all kids of gains NA

[dnegative]

I have been told by a few people that a 4 valve head is the way to go?
Its better than the stock big/small port heads but when push comes to shove and you start spending money your better off with the earlier 4 valve........... makes a bit of sense. Seems 5v heads were a fad that never caught on.


As for VVTI, not really sure it matters if your going to be over 40000rpm anyway? The whole idea of that shit it to improve daily drivability somewhat.

[oldcorollas]

and helps build boost fasterer.

5 valve costs more. that's why it never caught on

[trdee]

Theoretical discussions aside, the real world back to back comparisons tell me that the BT head is well worth the effort both in top end and area under the curve (especially with area under the curve on a turbo car). So thats what im going with...

[dnegative]

5 valve costs more. that's why it never caught on

Eh, I dont buy that. I think it was something that was experimented with but ultimately fell by the wayside.
Formula one engines are 4v heads

[oldcorollas]

at 20,000rpm, having an offset valve (compared to the other 4) will not help longevity

[Cuzzo]

I think what Mr 300 was getting at is if you port and polish (thank you gran turismo) the bigport head it will flow better than a stock bt head.

Which may be an option as BTs get rarer.

[Bazda]

For the average person who doesnt want to spends thousands on a head the 20v BT is going to be the better option to get higher power.
To bring the 16v head up to the flow rates of the BT head in stock form you will need to spend at least 2K minimum in porting it with larger valves.

Flow rates dont always translate to power output.
Also you could have a real high flowing head but has crap power until you hit say 6k.

We just got a Blacktop head mildly ported with 1mm OS valves which netted 240cfm flow through the intake at 9.2mm lift.
With more time on the intake def could get a bit more out of it.

Many examples in NZ making 270kw atw on 18-20psi, 4agze stock bottom end with stock blacktop heads.
Raise that to 25psi easy 300kw+.
Add E85 to the mix and 30-32psi then 360kw!! I have dyno sheets to back up all my data

Plus thousands of savings on head work!

Regarding turbo size. Compressor inducer of 53mm and exducer of 76mm will make 300kw (T3/4 style turbo). Thats whats on my car now and it makes 303kw @ 22psi on the 7agte with a stock blacktop head.
But with crazy response hitting full boost at 3800rpm.
Have used a 56mm inducer / 82mm exducer to hit 340kw @ 25psi. But its a bit laggier.
I've played around with alot of turbos and I know which ones suit the 20v head. Sizings of the turbo I use is a little odd and you cant get it in a Garrett turbo.

Compressor wheels is 1 part of the equation but ex wheels size plays a fairly big part as well. Id like to keep that a little secret as when I supply Turbonetics turbos I give my customers the best spec option from my testings.

[jfallen]

Bazada I swear they put something in the water across the ditch, because you lads always seem to get that little bit extra Maybe it's just the cooler mountain air... 3800 for full boost on a 1.8 that's making 300 is fantastic especially at only 22PSi (might I add I'm a little envious.) I suspect once my CA18 heads for the tuners that Full boost for me will be 5-600rpm later and I'll be needing 25-26PSi to get the job done (crappy 8 port head...) No doubt you've got your whole package perfectly matched.

I stand by my 54mm inducer 'rule of thumb' on the compressor however for mere mortals (such as myself) to crack the 300mark. There are of course exceptions to the rule (present company included) that can get that little bit more, from a fraction less, especially those from the land of the long white cloud.

[Bazda]

I know of a few people in Aus who are also making good power out of their 4agte's with 20v heads.

A guy I supplied alot of parts to (Fandio) made 275kw on 18psi using E85. But on a pretty average turbo (mixture of an RX7/Skyline turbo). Add a decent turbo to the mix and he would gain alot more power.
Runs a stock 4agze bottom end with a stock blacktop head using one of our plenums.

[maj]

Reading over this gives me crazy ideas of rebuilding my GZE with a BT head and a better supercharger (not against turbo's but just don't really want to go down that route; one turbo car is fun enough!), Bazda's plenum along with a few other goodies/upgrades, E85 optional.
Won't make anywhere near 300rwkw, but with the consideration of a stock GZE bottom end and a stock BT head would make it very no fuss and simple once aftermarket management was sorted.

[30psi 4agte]

Cuzzo: Crack on bro. You get to the point when you go all out on a 4a head( no matter waht type16v or 20v) that you can only fit so much air though a given port size. You can reach the point where the extra port walls on the 3rd valve of a 20v become a restriction.
Having two big valves and a big open port can simply fit more air. simple as that.

Jfallen : Mate... you speak the truth in real world language. There is no doubt in my mind that like me......... YOU have been there and tried that.

Rona : I totally understand what you are trying to say in your post.......... but there is simply no easy way to make 300kw at the wheels front or rear even the bloody steering wheel for that matter. 2L bottom end or even destroked 1.5L setup. Its an effort that only the commited will achieve.

TRDEE : I make 263 rwkw on 19 psi and a ........ Im drivin it to sydney from adelaide on pump fuel tune .... that one doesnt really prove the BT head any better..... sorry bro
Fandio prob did pick up the 60fwkw you talk of. Look....... id bet my left nut that it was not just changing the head. He prob went....... Im gonna up the ante hear, Change this, change that, put a black top head on, change the inlet manifold setup, and boom 60kw.
If he pulled the head and went im gonna...... put big valves in, do a kick ass port job fit a decent inlet manifold to my 16v .......in all honesty he would prob be about 60kw at the wheels better off.
On a real world motor thats pushin the genuine 300kwatw big port 4a or 20v 4a doesnt really make alot of difference.

BAZDA: you mad kiwis are always nudging that bar up in the 4a/7a hp... go to say ... even if there is something in the water or the cool NZ air ......i love it.

[trdee]

The head is totally stock apart from some supertech valvesprings. Stock valves, stock ports, exhaust manifold and bottom end were unchanged from the 16v setup. Of course the inlet plenum was changed, you cant use the stock plenum with any decent amount of boost. But putting the same scenario back to you... how much headwork have you done to get that kinda power out of your 16v head? And more importantly, what does your dyno plot look like in terms of area under the curve? When do you make full boost? From what Ive seen, the VVT on the BT head means boost (and power) down low and in the midrange shit all over a 16v from a great great height...

In any case, we are now (as always) going away from the intent of this thread. I dont want to have a debate on which head is better or worse here, as that then dilutes the original purpose of this thread, and nobody will end up agreeing anyway, plus there is already a thread for that kind of discussion anyway.. so lets just leave it and agree to disagree. We're all going to have bullshit fast A-engine powered vehicles at the end of the day, and thats enough to make anyone smile.

[RONA]

Rona : I totally understand what you are trying to say in your post.......... but there is simply no easy way to make 300kw at the wheels front or rear even the bloody steering wheel for that matter. 2L bottom end or even destroked 1.5L setup. Its an effort that only the commited will achieve.

Perhaps look at my build thread I know exactly what it takes to make 300+kw at all 4 wheels from a 2L as well. I know the components Vito has bought/ordered for his build and despite being short 100cc it is more comprehensive then the 3s build I just undertook to make well over 300awkw, hence my comments that on Eflex/E85 and enough boost it will shit it in. I'm not saying it is easy but I also know the build Vito is undertaking is far from basic.