Truenotch Posted August 28, 2009 Share Posted August 28, 2009 Found some more interesting info and think this is a fitting place to put it: Honda guys talking about soundwaves etc: http://www.team-integra.net/sections/ar ... icleID=466 I haven't looked at it in depth yet but the first bit that I read (bottom of the first page) is bullshit Notice that with invididual throttle bodies (ITB's) you lose this resonance effect because the reflected wave escapes out into the engine bay (or the atmosphere) and is not stored and returned by a plenum/acoustic chamber. ITB's do NOT use ram theory to get that extra kick at peak torque because they usually in race form do not have a plenum. In some street ITB's, a plenum is attached for practical reasons (sound deadening and filtering). They rely on very very large amounts of passive cylinder filling based on the piston's effects and use tuned air horn height and tapered diameter (with an S-shaped velocity stack opening) to get the N/A pressure boost effect The pulse doesn't 'bounce' off the plenum it does so off the general mass of dense air at the opening to the trumpet. Posted that mostly for the sweet pic of soundwaves bouncing into a OHV engine. Didn't actually read what they were saying about the different pleniums. The other link is cool though. Quote Link to comment Share on other sites More sharing options...
Mick Doohan Posted September 3, 2009 Share Posted September 3, 2009 Found some more interesting info and think this is a fitting place to put it: Honda guys talking about soundwaves etc: http://www.team-integra.net/sections/ar ... icleID=466 Some guy with a computer program: http://www.gt40s.com/forum/gt40-tech-en ... study.html And how NOT to do a set of trumpets!!! ive seen this car in person at total preformance in hamilton the intake noise it asounding and the power out put is ..ok.... but christ it sounds epic Quote Link to comment Share on other sites More sharing options...
Truenotch Posted October 15, 2009 Share Posted October 15, 2009 4ag 20v 4ag 16v Quote Link to comment Share on other sites More sharing options...
Testament Posted October 15, 2009 Share Posted October 15, 2009 Fiat Twin cam (124 CC) 42mm inlet valve 36mm exhaust valve Somewhat Lame SSR. still much better than a pinto though. Quote Link to comment Share on other sites More sharing options...
BobbyBreeze Posted November 1, 2009 Share Posted November 1, 2009 Brad, have you got any further regarding your XEV research/porting? Also, something a mate has been talking about which is interesting - late model 4af/7af heads have better ports than 4ag and will outflow them when worked. They can run bigger cam's than the 20v's which is apparently the major limiting factor of them Billzilla in aussie is building up a 4a-fe for his Starlet that he's looking to get ~250hp out of. Sweet inlet ports. Also, found this which i thought was cool. Narrow angle FTW. Interesting that narrow with steep ports is now the standard rather than the old wide angle performance heads. 1990's F1 head cross-section Not mentioned here are the Nissan SR16ve/SR20ve's. Have been looking them up and sounds as though they have the potential to have more power than the Honda motors. The N1 sr16ve is 200hp from a 1600cc. Have heard of race motors spinning to 12,000rpm and I've heard some stupid flowbench numbers from them. Only thing is its a bit of a pain to RWD them. People getting 200whp out of the sr20ve's with minor mods - exhaust, n1 cams and piggyback ecu to let them rev. Quote Link to comment Share on other sites More sharing options...
xsspeed Posted November 1, 2009 Share Posted November 1, 2009 Is that 250hp on an NA 4afe? Quote Link to comment Share on other sites More sharing options...
BobbyBreeze Posted November 1, 2009 Share Posted November 1, 2009 Yep. Thats with 280degree cams... I plan to run it to 9,500rpm and although I'm expecting about 240hp from it, it should still drive as well as a standard engine does around town. To back up the estimated power figures of the 4AFE, here's an example. As fate would have it, a friend of mine overseas has built an engine almost identical to what I will be building. It's in an off-road buggy and on an engine dyno it has made 248hp at 9,000rpm. Quote Link to comment Share on other sites More sharing options...
Brock-Lee Posted November 1, 2009 Share Posted November 1, 2009 yup yup. But alot of work is needed in the combustion chamber to achieve those sort of powers. read the link. pretty interesting read. For the average joe road engine a g head would be better but for a balls to the wall race motor the benefits would be seen. EDIT: beaten Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 1, 2009 Share Posted November 1, 2009 Bill does some pretty impressive work to toyota motors. Pretty amazing to get that power from a 4AFE This is what you have to do to fit africa cams to a 20v Quote Link to comment Share on other sites More sharing options...
nothingsfree Posted November 1, 2009 Share Posted November 1, 2009 There's no doubt in my mind that the S2K motor/box is the best NA 2 litre package you can get for a RWD car.But it's what 240hp for $8-9k? for an S2k setup? Or 210hp for $2-3k or so with an altezza package. I'm not suggesting it because I've got one, but the altezza setup is definitely the most cost effective $/hp for a reliable 2 litre NA setup that you can wail on all day long. I would take an F20C over my beams motor any day of the week.... But they're too expensive! And far less common, so a lot harder to replace if need be. Using standard Altezza block, spending some $$$ on things like nice extractors, ECU and throttles perhaps, and you might be 20hp down on F20C but only spent half as much. And when/if your motor blows up, just go buy another standard block for cheap, put your fancy bits on it, and be up and running again. Rather than completely up the shit, having to replace an expensive (although admittedly superior) motor, or having a fully built motor that you've spent $$$$ on blow up, which leaves you back at square one. Mate is running a Altezza 3s in his ae85 (The one featured in NZPC few months back). His is a completely stock engine only mods are Link ecu, and 4age itbs. Its even still running stock extractors, he got 205rwhp when he got it tuned. Agree that for the price, the beams 3s is pretty hard to beat, and readily available... Quote Link to comment Share on other sites More sharing options...
Roman Posted November 1, 2009 Share Posted November 1, 2009 Sounds like a pretty optimistic dyno reading to me, tbh... Not bagging his project or whatever, just seems like a high power output for minimal mods Quote Link to comment Share on other sites More sharing options...
Testament Posted November 1, 2009 Share Posted November 1, 2009 Not mentioned here are the Nissan SR16ve/SR20ve's. Have been looking them up and sounds as though they have the potential to have more power than the Honda motors. The N1 sr16ve is 200hp from a 1600cc. Have heard of race motors spinning to 12,000rpm and I've heard some stupid flowbench numbers from them. Only thing is its a bit of a pain to RWD them. People getting 200whp out of the sr20ve's with minor mods - exhaust, n1 cams and piggyback ecu to let them rev. guy in the fiat club races a pulsar with sr16ve head on a sr20 block and it does go very well indeed. Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 1, 2009 Share Posted November 1, 2009 Sounds like a pretty optimistic dyno reading to me, tbh...Not bagging his project or whatever, just seems like a high power output for minimal mods Remember your factory Redtop beams had 170hp atw? I think it's possible to get that figure with aftermarket ECU etc.... Keen to see how the Carina motor will go. Quote Link to comment Share on other sites More sharing options...
nothingsfree Posted November 1, 2009 Share Posted November 1, 2009 Sounds like a pretty optimistic dyno reading to me, tbh...Not bagging his project or whatever, just seems like a high power output for minimal mods I havnt seen any other dyno sheets for a similar setup, so I cant compare. What are they normally making? Quote Link to comment Share on other sites More sharing options...
cletus Posted November 2, 2009 Share Posted November 2, 2009 That said to confuse you further, a 4V Cleveland head is considered too big for street use due to insufficient velocity (at least according to all the experts out there). So why is it then that many Mitsi 4V ports are bigger per cylinder capacity and so velocity is less. The only reasonable answer is that all the experts are well and truely wrong Steve the mitsi can probably get away with a bigger port because the fuel is squirted directly at the valve from the injector rather than having to get dragged out of a holley and make its way down the manifold and port. the older engine needs velocity to keep the fuel atomised properly Quote Link to comment Share on other sites More sharing options...
fuel Posted November 2, 2009 Share Posted November 2, 2009 and mitsi realised they fucked up making the port sizes too big so later made the port sizes smaller in the evo1 onwards, and did away with that cyclone dual-runner manifold. more or less the same as toyota with the bigport/small port TVIS engines. Quote Link to comment Share on other sites More sharing options...
forced Posted November 2, 2009 Share Posted November 2, 2009 It's more a case of the japs agreement to limit motors to 280ish horses. By limiting the power output the only way to make improvements is to increase mid range torque by gradually increasing the CR, making longer cams and upping boost. The smaller ports help midrange torque at the expense of max possible flow, which of course isn't needed with the limit of HP. Steve Quote Link to comment Share on other sites More sharing options...
fuel Posted November 2, 2009 Share Posted November 2, 2009 clearly that wasn't the case with the likes of 4A-GE's which are no where even near 280hp (barely even half of that). Quote Link to comment Share on other sites More sharing options...
Testament Posted November 14, 2011 Share Posted November 14, 2011 wow didnt realise this thread was that old/wow im getting old anyway came across this about the volvo 850R BTCC wagon heads which is quite interesting/loltastic http://www.clubgti.com/downloads/Volvo_850_head.pdf Quote Link to comment Share on other sites More sharing options...
Yowzer Posted November 14, 2011 Share Posted November 14, 2011 That is quite a good read. Quote Link to comment Share on other sites More sharing options...
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