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It would be interesting to get your fuel map dialled in, and then see what the shapes look like.
I reckon you're probably now at the point where only a few mm worth of changes to runner length will make a reasonable difference either way.

Or something else to think about.

Similar to how boost is a sign of restriction, as in, the head cant consume all of the air that is provided by the intake manifold.

In an NA car you get a pressure drop when the head is hungrier for air than what the intake can provide.

Perhaps you're at the limit of the ITB size/setup? Maybe its at the point where bellmouth shape has become super critical and you're getting
Or that things like rounding the leading edge of the throttle plates and smoothing down the bolt heads.

Or maybe whatever you do from here, the pressure will always drop because the airspeed in the runner is so high that you get a venturi effect bernoullis principal or whatever, pulling air out of the map sensor hose so it always reads lower as the airspeed increases.

Have you considered fitting a beams 3SGE intake manifold?
To make it fit you may also need a beams 3SGE head. And block.
 

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Some great skills in the header fab, and the 16v looks at home under the bonnet....

I see a bunch of discussion about camshaft selection and timing, I didn't see any mention of compression ratio.(maybe i missed it)

You probably are all over this but i'll carry on maybe for someone else's benefit..

It seems that a wise camshaft selection really needs to be backed up with the right compression ratio, EG: a bigger cam or agressive cam timing generally reduces dynamic compression, so big cams and around 12:1 (or a bit more) may run happily on pump gas.. you may have reduced the dynamic compression with the bigger camshafts and it needs the compression bumped up to make most of the new cams..

/ have you considered a 2zz?

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Runner  length have played a lot with.  The trumpets on there at the moment aren't the right length.   Either need to go bit shorter, or try to fit something longer in there, as at the moment there should be another peak (2nd wave) just past 9000rpm.  running out of room though.  either way  it will just move the peaks around rather than an over all power gain. So have put trumpet length down the list while trying to find whats holding it back.

bigger itb's is looking like its worth trying. 

 

when you beat me at the oldshool drags i will consider a beams dave..

 

compression  is  around 13:1  i haven't got all scientific about it and cc'd the chambers  etc.   but it has 11.5:1 toda pistons. .8mm trd head gasket and a .5mm head skim. which works out ballpark 13:1

 

 

 

fuel map looks like so.  this is what its running on now, unchanged from old stock valve head.  was pretty much flat line afr  from 4000 -9000rpm before head swap.  it does some weird shit at 2400 wot hence the massive peak. but is a non issue at that engine speed.

 

kp-fuel.png

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What duty cycle do your injectors get to at the moment?

 

Maybe try go way bigger spray just on open valve period rather than back of valves?

Staged injection + variable length runners? Methanol?? :D

I reckon it would be interesting to setup a pressure sensor on an exhaust runner, and then find out if you see pressure peaks/troughs like you do on the intake side.

You could find out the actual tuned length of the manifolds you've made. Then it might tell you a tale about needing to be a lot shorter or a lot longer. (or it might be sweet as is!)

I remember somewhere seeing someone do this. They had a screw in fitting which then had a long hard line coming off it with a long coiled section in the airflow to dissipate the heat before it gets to the sensor.

From memory if you're doing it right the exhaust pressure only goes up to 20psi or something like that.

Can get an 80psi sensor cheap enough.




 

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About 50% max d/c, they are caldina gtt injectors. (normally i wouldn't use rubbish 3s parts but they were hanging around)   Will have a go at messing with the injector timing, running at 400 at the moment.

 

Was planing on doing outboard /semi ouboards at some stage.  but want to get the rest dialed in first, plus will need to upgrade my ecu .

 

Might have some stuff hanging around to test exhaust pressure.  Going to shorten the collector length see what that does. So will weld something on when i have them off.  maybe test post collector too

 

Biggest concern is that it had almost zero effect putting bigger valves in the head,  same deal with the throttles.  I'd be more happy if it went slower than stay the same, at least id know i'm going in the wrong direction.

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So did the 47mm throttles still net a 2-3kpa restriction? I probably would take this value with a grain of salt - as you say there is only 1kpa resolution and it could be easily pulling a couple kpa just due to dynamic pressure. You definitely don't have an intake flow restriction above 5500rpm with oversize valves and big ITBs, this is a wave tuning and cam timing issue IMO. 

 

What is your goal with this motor? You put bigger cams in and seems you are trying to keep all the midrange of the B's with the top end of the C's. You can't really add 10 degrees duration and not expect a decent drop in mid range torque. Either cam it smaller, have your midrange and play with pipe tuning so it doesn't die to badly up top. If you want the top end you have to sacrifice some decent mid range and gear it close & short, it is a 1600cc 4age after all. 

 

For me the first thing would be to do is to dial your cams in properly vs. TDC and see what centrelines they are actually on, seems to me there has been some problems here (and its free to do). Once you have your actual centrelines, you can see what your open/closing events are which will help evaluate whether the cams are in the right ballpark or not. Engines can respond well to timing changes of 2degrees and the closer they are to being 'correct' for what the engine wants, the more relative power will drop off as the timing events are incorrect. 

 

From here a good look at your intake/exhaust CSA's and lengths/transitions would be the next thing I'd do. 

 

After this I think you are at the point where you need to start dyno testing or simulating because NA engines are notoriously hard to evaluate & develop when you get to the last 5-10%, more so when you have little instrumentation. 

 

Have you had the head flow tested with a velocity probe? What about if the air is going supersonic and becoming turblent?

 

Supersonic is only an issue during blow down of the exhaust port, and even then it is debatable. With his small lift I doubt he has turbulence issues.  

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id be trying a bit more exhaust stuff, I have a hunch the collector is too big/steep angle.

 

Specs i built for a formula atlantic car, 22" primaries 1.75: dia, 12deg merge collector (15 deg would have been nicer but autobend collectors are 12 and easy to get), 2.25"OD choke with 300mm long cone/megaphone to 3" diameter, then a 2" long reverse cone back to 2.5". had a short 2.5" exhaust/muffler combo being at open wheeler. It woke it up a shitload compared to the 2" primary short runner/steep angle collector straight to 2.5"exhaust that came off it, the owner said it was an entirely different car.

 

id probably run primaries around 24" x 1.625" OD with just an autobend merge collector  - just clean the insides a bit with a sanding roll. id go for a choke a sniff under 2.25", say about 54mm and do a 54-63mm 300mm cone/megaphone.

 

would be interesting to see how much difference just changing the collector setup to the above would change it (I assume your running 1.75" primaries)

Exhaust stuff is tricky tho I'm pretty sure its some kind of black magic

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I did dial the cams in properly  with a degree wheel once i stopped being lazy.      would have been happy to loose some midrange for some top end gain, going from the 193b to the 193c.   But  with the 193c at  Kelfords recommended centerlines,  it lost power everywhere  over the 193b's,  except a little gain over 8000rpm.  which is past peak power, so of no use.  dialing in 10 advance on the inlet & 10 retard on the exhaust  (same settings as i was running the 193b) gained back all the power plus a little over the 193b,  minus the gain it originally made 8000+

 

The manifold pressure still looks just the same  with the 47mm throttle vs the 45mm's

 

 

Will be trying a few things with the  collector length and diameter.    I did have a long merge collector on it ages ago and played with collector diameters,  from 1 3/4 up to 2.5" . but that was all on my old setup, so worth a revisit.   currently it has 38mm od (about 35mm id) extractors  with a 300mm 2.5" straight collector after the merge. then a sudden step down to 3"  in an attempt to simulate the exhaust ending.   my other extactors are basically the same design but are 44.5mm tube, with the same 300mm 2.5" collector arrangement.  they make the same power 6000rpm onwards.  below 6000rpm they make less power than the 38mm primarys.  I havent tired the 44.5 extractors on the big valve head yet.  

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the atlntic headers may well have been 1.625" now that I think about it, it was a while ago I did them, I think for your setup youre better sticking with your 1.5" primaries over the 1.75" but yeah it would be interesting to see the results of the collector testing. I reckon cones/megaphones off the collector is the go, well at least ive always had good results anyway. I'm far from an expert and definitely haven't done any where near the amount of exhaust testing on a single motor that you have. Maybe start with a 2" choke and work up from there. I know that specifically with SR20VE motors most of them lost power in a big way when choke sizes went over 2.25" so a 4age would probably be happy with something fairly close to 2" the atlantic I went slightly bigger as it obviously has the gearing to keep the power in a 1200 rpm window and they were spinning to 9. We also did the tuned primary length at 7500 as this was the lowest rpm it dropped too on gear changes. This made it a lot more driveable too according to the driver. Its all just a half educated guess at the end of the day, at least you have done a heap of testing so have a decent amount of data to work from. look forward to seeing how you get on

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Found these pics from when we built the headers for the Ae82 racecar. They have been making up to 200hp atw with a standard head without being a restriction. Seem very similar to what you are describing nick, except for having a step from the 1.625" tube up to the 1.75" about 100mm from the flange. I think this is largely to do with stepping it up from the port side as gradually as possible. Can't remember if the tacked up photo with the sizes written on it is how it ended up welded - this doesn't show the step like you see in the final finished pics. 

 

These give a fairly flat torque curve from 4500-9000rpm. It's getting a CNC ported head and bigger throttle bodies next so we are thinking these might not quite be up to the task for 230-odd hp. 

 

IMG721.jpg

IMG758.jpg

IMG759.jpg

 

 

 

 

I feel your pain for not being able to pinpoint where the restriction is! I'd say the intake is fine and exhaust probably isn't too restrictive also, but a bit of tuning wouldn't go astray.

 

Our experience has been that cams can be very hit and miss in their manufacture. Even with a certain spec sometimes they react completely differently. Have been through probably 4-5 sets of cams due to them not quite being right. Can't speak for the Kelford stuff, never used them, although another fellow competitor has and struggled to make 170hp on a very similar setup to what we've been running. I guess all I'm saying is don't assume the cams aren't the culprit here. 

 

 

+1 for variable length runners. Keen to see this! I've had a few ideas of how to do relatively simply but never any more than that. 

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Hey rhyscar.

That's very interesting. I haven't done a lot of 4-2-1 but when I have I spec the first collector length at peak hp and the second collector at peak torque or sometimes under depending on engine use. And the choke diameter for the peak torque becomes the secondary runner diameter and the choke for peak hp becomes the second collector choke. Seems to give good results but unsure if that's the "correct" way to spec them never tested vs 4-1 headers directly tho. Interesting that your megaphone is so far from the final collector. How did you spec that? I haven't played with stepped headers tho am aware of the merits. Just a hard sell for most customers. Would build on my own personal headers. My headers I only get one shot at unfortunately. Would love to do some actual header testing. But would be very time consuming.

Out of interest who do you use for your cams?

Cheers nick

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Same questions..    and what duration  cams have you tried and ended up with?  i take it this is on a blacktop?

 

 

Both sets of extractors i have, are a bit on the long side primary wise.  The 1.75's i can cut down 100mm or so easily, so will likely try this to see if it has any effect before building another set.  maybe try a different merge and collector also.

20160409_135209s.jpg

 

 

Brother is gonna make some choice wood spacers for my inlet trumpets,  so can test different trumpet lengths easily.  From what i figured awhile back, if they are near 50mm over the current length. should pull another wave(currently out of the rev range at 9000+)  down to around 8000rpm. which should give an ok top end gain. and maybe drag that peak at 5600 back down a bit.

 

variable intake  would be nice. but would be alot of drama to make it work properly.   kinda like the simplicity of it how it is now

 

 

I was kinda looking for over all gains,  the way its responding to changes.  Almost as though its breathing  through a restrictor.  Hence the bigger throttles.   Maybe time to give up on that idea and get back to pipe tuning.

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Yeah this is a blacktop hence the duration is a lot lower than what you can get away with in a 16V. I've heard of some rally guys using up to 315deg intake durations which is nuts. 

 

These are the cam specs they were originally designed off by Snow. Every iteration from here has been slightly lower in duration, down to 300deg but lift staying the same to prolong valve life/prevent float on the way shut. Please don't share specs apart from here as they were a special one-off by Snow - would be interesting to see what Robbie has to comment though. 

thumbnail_Corolla_Cam_specs_001.jpg

 

 

I wonder if you are at the stage where the 4-1 header design is too peaky to get the cam working properly. I agree that in theory with all the stars aligned and the perfect gear ratios 4-1 headers will make more power, but the slightly broader range of the 4-2-1 design makes it work on the lower side of peak HP as well. Motorbike guys kind of have this theory and run staggered trumpets between all 4 cylinders as well as the Z6 coming with these sweet things;

2009_Kawasaki_ZX6R_ZX600R_09_INTAKE_FUNN

 

 

Harris Pipes in christchurch specified the lengths for us, they have a sister company that are acoustic engineers. From memory the expansion chamber should of been a bit closer, but the crossmember was in the way and it wasn't really practical. If anything it just gave it better torque through the rev range. Unfortunately I made the mistake of not emailing a copy of the specs to my personal email so would take some digging to find it. 

 

Most recent dyno excursion with said very average cam (reground from standard base circle who knows why), E85, 3sgte injectors, COP conversion and 13:1. That only lasted a few laps before the valves were poked hence the re-refurb. 

Dyno%20tune%20feb%202016.jpg

 

 

 

 

It's not the valves which are the restriction? seems odd that changing things either side of combustion chamber makes no difference, maybe the restriction is in the head. 

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Thats pretty impressive power.

 

There was almost zero change going to big valve  head.   1.5mm bigger on inlet 2mm on exhaust  (same size as atlantic)   it  gained a very tiny amount up top and little loss in midrange. but hardly anything worth talking about.     I done the porting myself, so not expecting it to be anything ground breaking.  but at least thought would have been some change.   the head previous has similar work done to it. but obviously the big valve head has had more taken out, to suit the bigger valves & valve seats.  i added the 47mm throttles after this and still the same.   

 

I'm  thinking the 4-1's on there are tuned to too lower rpm to make much up top.  but yeh possibly work better with 4-2-1's either way

 

 

 

Edit:  Just noticed your 4-2-1's are grouped different to normal.  any reason for this?

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Hytech exhausts stand by that pairing as well. It sequential pairing related to firing order. So both exhausts pulse go out one collector instead of each collector. It's definitely the minority but hytech make some of the best Honda and Atlantic headers on the market. So there must be something in it i guess. Hit me up on pm with some engine and cam specs and I can give you some specs if you want to try a 4-2-1. Looking at Rhys headers I'd expect to end up with similar sort of dimensions with the way I spec them which is encouraging as Harris are much cleverer than I am.

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Hey, dont want to sound like too much of a numpty as I have only briefly skimmed over the info here - but has your exhaust got anti reversion stubs? Or are the engines that see benefit from anti reversion stubs poorly designed 8 valve engines and not those such as the 4age?

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