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Location:
Barbados
Registered:
October 2004
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What head specs for 4agte
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Wed, 02 February 2005 17:01
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heh guys im buildin a 4agte im usin bigport 16v head, hks 264 intake 272 exhaust, small port valves( i heard they are larger)
ported head and thats it
ok guys i want advise from all experienced parties on what here is good and what is nnot also what are better options on head work on turbo 4as alltogether
so basically
what cams
what valves( size)
portin/ polishin
valve angle jobs?
etc etc thanks
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Location:
Canberra
Registered:
May 2002
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Thu, 03 February 2005 12:22
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a freind of mine who deals with them told me not sure if its correct info but what valve size would help improme big port flow is there any specific mm over any of you would suggest? and what about my choice of cams? will a bigger exhaust cam benefit along with more exhaust portin. well what do u guys think?
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: What head specs for 4agte
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Thu, 03 February 2005 12:44
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272 and 280 sound very long duration for turbo cams!
what rpm do you expect to stop blowing the intake charge out through the open exhaust valve?
for NA, those cams would kick in around 4000+?, with turbo, how much higher does it go before your cams are efficient?.. or is it all in the lobe centreing?
Cya, Stewart
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Thu, 03 February 2005 14:43
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its 264 and 272 no 280 , well thats why im askin becuz i want to know if these specs will make astrong turbo motor or a weak one, what cams would u adbise my maximum prefered hp is about 300whp at anythgin around 18-20psi
i want to build this motor mainly for response so im tryin to get 200whp at 8-10 psi comin in around 2500 rpm or sooner usin a t28
and a rebuilt gze bottem end usein 8:9:1 pistons and a knife edged balanced gze crank.
should i blue print and balnce other internals aswell?
also usin full fuel and spark management. usin a 034 stage1c ecu
for those of u who dont know about it here are specs http://www.034efi.com/034ECUSTGI.html
and im using a tubular manifold with external wastegate, also doin a v mount to shorten pipin for better response, i will also be satisfied with 250whp at 15psi or so but responseand 0 lag is my main goal so any advice on what parts i should u for my goals please let me know thanks guys
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Thu, 03 February 2005 14:46
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oh and 450cc injectors
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Thu, 03 February 2005 22:35
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| Quote: |
272 and 280 sound very long duration for turbo cams!
what rpm do you expect to stop blowing the intake charge out through the open exhaust valve?
for NA, those cams would kick in around 4000+?, with turbo, how much higher does it go before your cams are efficient?.. or is it all in the lobe centreing?
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Hey Stewart
Yes, they are large cams for a forced induction motor, but I'm happy to experiment with my adjustable cam gears to change the lobe centres & see what we can do. Its all about experimentation....... we'll see how it goes. Maybe the cams will be for sale for a naturally aspirated screamer if it doesn't work out! Although the advertised duration is 280, the duration at 50 thou is actually very close to the HKS 272's, which have been proven to work well in many turbo applications. with 110/110 phase, the overlap at 50 thou is zero degrees.
Cheers 
Phil
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Location:
Melbourne
Registered:
May 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:09
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Yeah guys im very interested in this too as im still trying to decide what head to go for. BIG or small.??
I want to know if there will be any more or much more lag if i use the BIG port head as i want to acheive some pretty decent power figures of over 200rwkw and have the bits to do this but i dont want excessive lag, if any!
I know its gonna be hard but your thoughts please.
Jezza
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:16
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Thats a hard question to get a real answer for, the 6 GTE's that I can think of are all RWD, and therefore use the bigport head so that the RWD manifold can be used, rather than cutting & shutting a smallport FWD manifold.
If your turbo selection is carefully planned, I can't see lag being an issue for you with either head. I certainly can't complain about response on mine, and KE382TG's is even better with the smaller GTR exhaust housing (19psi by 3000rpm?) and seems to lose nothing to mine up top either.
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Location:
Melbourne
Registered:
May 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:25
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Yeah i was leaning towards the big port head because i have a beautifully polished RWD Bigport manifold and the turbs im using is absolutely ideal. Its a brand spankin GT28RS Garrett aka 'Disco Potatoe'.
TE72_Turbo- What are the specs on your motor? what sorta power you making?
Jezza
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Location:
Canberra
Registered:
May 2002
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Location:
Melbourne
Registered:
May 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:40
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Just the standard Disco 
Jezza
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:44
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See how it goes. I know that they have good response on the 2 litre SR20, but i've been too chicken to try a .86 housing on mine cause I don't want to lose response, however it will help top-end power with the additional exhaust flow. 
Anybody on here actually used a disco potato yet?
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Location:
Melbourne
Registered:
May 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:45
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What will it affect and will it affect it in a big way do you think?
No im worried man! 
JEzza
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:50
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Don't stress  You can always change housings once you get it running if you're not happy anyway, its not a big deal. Being ball bearing helps response anyway, remember mine is only conventional bush bearing, so i'm on the back foot already compared to your core.
How much difference is it likely to make? Its hard to say for sure, but my car has a .64, and Ke382tg has a .48 housing, and he gets full boost a good 500-700rpm before I do. There are other factors too though, I have larger and longer intercooler plumbing, and a bigger front mount, so these could affect the response too.
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:51
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Sorry eurospec86, we're getting a bit off topic here, i'll stop hijacking your thread now 
Phil
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Location:
Melbourne
Registered:
May 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 00:56
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Im sorry also.
Will pm you soon.
Jezza
Bump again 
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 11:46
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its kool i too am ponderin myy turbo what do u guys think of these specs i found them on mr2oc.com
"Hi all,
I happen to be talking to a nissian specialist (fairlady motors) about turbo AW11. He has what he thinks is a good match for the 4ag. It's a hybrid turbo that he put together from some leftover nissan parts. The only negative I could find was the there are a few very small dings on the compressor wheel (look at the last pic). He assured me that it wouldn't make any difference. Here are the specs;
Ball Bearing center
Water cooled
Internal Wastegate
Standard T2x manifold flange
Compressor side from S14:
T-28, AR 0.60, 60 trim
Exhaust wheel is from s14:
62 trim
Exhaust housing is from an R34:
AR 0.48
The turbo should flow up to 300hp, and with the ball bearing center and small exhaust housing it should have minimal lag. The guy wants $350 for it. If you are interested let me know and I'll give you his contact info.
-Rob"
head input is still welcome aswell thanks
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Fri, 04 February 2005 14:03
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It should boost up like a demon
Considering how quick the response is on ke382tg's 4AGTE (literally no lag) with the GTR 0.48 A/R housing and conventional bearings, i'd say that turbo would be REALLY punchy down low in the revs.
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Fri, 04 February 2005 18:55
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sounds good would my cam specs hinder thsi quick spool? 264 IN 272 exh, also is bigger exh better for turbo?
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Location:
Canberra
Registered:
May 2002
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Re: What head specs for 4agte
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Sat, 05 February 2005 00:41
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That I couldn't answer I havn't experimented enough with cams, but will know soon
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Location:
Brisbane
Registered:
February 2003
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Re: What head specs for 4agte
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Sat, 05 February 2005 02:18
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Definitly go nice and small on the exhaust housing. Mine is .70 AR and quite laggy (though it does go very hard once on boost). As TE72 said the GTR housing would be ideal.
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Tue, 08 February 2005 15:27
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bump for more info
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Location:
u.s.a. south
Registered:
April 2004
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Re: What head specs for 4agte
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Tue, 08 February 2005 16:41
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I'm trying to understand the effect cams have on the torque curve.
I'm interested squeezing the most torque out of a 4agte rather than go for peak hp numbers as is so common nowadays.
Old school american cam grinders always had more duration on their intake lobe than the exhaust. Even the automakers did for their early turbo cars.
Also on a u.k. site, I've seen two 'long time' ca18det guys run a hks or tomei INlet 256° or 260° cam ONLY, and we're pretty excited about the significant gain in performance.
Here is a nice 1.8L 7agze posted, running a sc14.
http://www.twincam.org/forums/index.php?showtopic= 9681
He too chose more inlet duration on his hks cams... 264°in/256°out
The folks I see setup cams like this really seem to know what they're doing.
I definitely going to try it, but was just seeking comments on it.
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Location:
brisvegas
Registered:
December 2004
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Re: What head specs for 4agte
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Wed, 09 February 2005 07:50
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just reading up on 4ages last night and i came across something commenting on cams + durations. (try google search for 4age cam duration or similar and see how you go.)
from what i gather setting up the exh duration one 'step' lower than inlet is to do with torque and where in the band it comes on. you also have tuning by using adjustable cam gears to bring it in or out - i.e. retarding inlet slightly, while advancing exhaust, or vice versa, or advancing and retarding both in step.
as the page says tho you really need to be doing this on a dyno so you can immediately see whre the results are. you also need to be thinking about the sort of tuning you want - the page mentions for example accel from 0 type tuning, or tuning for between specific rev ranges (usedful for track type events i thinking where you would be trying to keep the RPMs up and pulling, and accel from 0 type tuning is not much use)
aaah i think ive found it :
http://www.club4ag.com/faq%20and%20tech_pages/4A-G E%20camshaft_story.htm
dont mind what i wrote before go and read it from th hoss' mouth
Cheers
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Location:
Barbados
Registered:
October 2004
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Re: What head specs for 4agte
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Tue, 15 February 2005 19:17
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so a bigger intake is better for response as opposed ro bigger exhaust?
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Location:
Kingaroy
Registered:
July 2004
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Re: What head specs for 4agte
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Wed, 16 February 2005 07:13
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Ok I'm using a set of 288 degree and 304 degree cams with my setup, honestly I think I went a little overkill. These have been tuned with adjustable cam gears and start making power at about 4500 rpm the turbo starts to spool just after this so its a bit of a bitch for normal driving. However the turbo carrys strong all the way thru to 8800rpm at 29 psi so I'm happy with the setup, and on the race track i don't really go below 400rpm anyway.not the best for quick response but plant your foot in 5th gear and you go noware.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: What head specs for 4agte
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Wed, 16 February 2005 08:16
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| subsonicaudio wrote on Wed, 16 February 2005 18:13 |
Ok I'm using a set of 288 degree and 304 degree cams with my setup, honestly I think I went a little overkill.
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that is quite possible.... those cams are more like what would be used for a 'just streetable' NA setup, so with turbo, you are effectively increasing the duration... you are likely blowing a lot of mixture out the exhaust until maybe 5000rpm or so...
what is the lobe seperation currently?
Cya, Stewart
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