msupra1 Posted October 26, 2016 Share Posted October 26, 2016 I am making 900bhp through a BW 66mm turbo. 10:1 compression, pretty responsive setup I would say. Doing a couple changes to my setup, and one of the things I'd love to add is an aftermarket intake manifold. I just love the way they look and hoping to gain some more power with one. I am looking into something such as Greddy. Do they add any additional lag? I've read that as long as its not a cheap ebay manifold and a quality piece, it should only have positives to this mod? One thing I am trying to avoid is adding additional lag. I get full boost around 4400rpm and redline is 8500. Love the current power band. Cheers Quote Link to comment Share on other sites More sharing options...
el_bandido Posted October 26, 2016 Share Posted October 26, 2016 Remortgage your house and put individual throttle bodies and a well designed air box on. Other finance options include putting spare family members on eBay. Quote Link to comment Share on other sites More sharing options...
msupra1 Posted October 27, 2016 Author Share Posted October 27, 2016 Just looking for real world comparisons. So anyone who put one on, I want to know your impressions... if it added lag and such. Quote Link to comment Share on other sites More sharing options...
a98pmalcolm Posted October 27, 2016 Share Posted October 27, 2016 1st I've heard of extra lag from an after market inlet, if anything its better flow of air as there is less harsh angles. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted October 27, 2016 Share Posted October 27, 2016 Here's a decent example. [video=youtube;cNNFPGjny-o]https://www.youtube.com/watch?v=cNNFPGjny-o Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 27, 2016 Share Posted October 27, 2016 I doubt they would add any extra lag at all, the volume change is minimal in terms of air flow volume. What i would be concerned about is how equally they flow air to all ports, something the stock manifold *WILL* have addressed, but possibly not with aftermarket. Quote Link to comment Share on other sites More sharing options...
msupra1 Posted February 18, 2017 Author Share Posted February 18, 2017 Just wanted to bump this thread and see if anyone else have any experiences from upgrading their intake manifold or have knowledge on it Again from my understanding there should be some 'minor' low end losses but hoping this wont affect the way the turbo spools. Getting ready to buy one but don't want to be disappointed with the affects on the low end (if it happen to be bad) Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted February 18, 2017 Share Posted February 18, 2017 I doubt they would add any extra lag at all, the volume change is minimal in terms of air flow volume. What i would be concerned about is how equally they flow air to all ports, something the stock manifold *WILL* have addressed, but possibly not with aftermarket. Chris, have you any experience with twin chamber plenums? The audi 5 cylinder guys rave about them, but I'm yet to see them being adopted by Japanese car tuners. Quote Link to comment Share on other sites More sharing options...
mwilkinson Posted February 18, 2017 Share Posted February 18, 2017 I'd ditch an aftermarket manifold in favour of opening up a factory intake and porting it. That's what was done on mine. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted February 18, 2017 Share Posted February 18, 2017 I'd ditch an aftermarket manifold in favour of opening up a factory intake and porting it. That's what was done on mine. Thing is, the stock setup was a compromise for the sake of packaging, there are good, proven gains to be had with a decent plenum. But it generally means relocating the battery, which is a pita if you value your boot space (although I suppose one of those smaller li batteries might go in one of the rear wings) I've always loved the vielside plenum, shame they're so rare Quote Link to comment Share on other sites More sharing options...
Sheefa Posted February 18, 2017 Share Posted February 18, 2017 Thing is, the stock setup was a compromise for the sake of packaging, there are good, proven gains to be had with a decent plenum. But it generally means relocating the battery, which is a pita if you value your boot space (although I suppose one of those smaller li batteries might go in one of the rear wings) I've always loved the vielside plenum, shame they're so rare I have the battery relocation to boot and have kept all the space with a slimline battery after having the SRD Greddy style manifold installed. There are definitely gains to be had by upgrading to a reputable make. Quote Link to comment Share on other sites More sharing options...
V8KILR Posted February 18, 2017 Share Posted February 18, 2017 When I had a custom aftermarket intake manifold made (with an 80mm throttle body), it lost around 500 rpm of spool when I went back for dyno testing. It had internal trumpets, so not sure why this happened? Quote Link to comment Share on other sites More sharing options...
msupra1 Posted February 18, 2017 Author Share Posted February 18, 2017 500rpm of spool is a lot! See that's what I'm afraid of. I am thinking to maybe stick with the stock intake and clean it up by shaving the throttle body clean and removing anything from it that's not necessary. Quote Link to comment Share on other sites More sharing options...
V8KILR Posted February 18, 2017 Share Posted February 18, 2017 I wish I'd stayed with the stock intake. You can make 1000hp on stock intake, so no need to upgrade for power reasons for most people, only for cosmetic reasons. Quote Link to comment Share on other sites More sharing options...
msupra1 Posted February 18, 2017 Author Share Posted February 18, 2017 Yes honestly I am doing it mostly for looks. Just love the way it looks. If it's adding significantly more lag then I wouldn't go that route. Quote Link to comment Share on other sites More sharing options...
mwilkinson Posted February 19, 2017 Share Posted February 19, 2017 500rpm of spool is a lot! See that's what I'm afraid of. I am thinking to maybe stick with the stock intake and clean it up by shaving the throttle body clean and removing anything from it that's not necessary. Keep it simple. I'd modify your stock intake and retain the factory fit. No battery, fuse box or pas reservoir relocations or cutting holes in your car. Quote Link to comment Share on other sites More sharing options...
msupra1 Posted February 23, 2017 Author Share Posted February 23, 2017 So I've decided to stay with the factory intake. Any suggestions on what can be done to better improve it? I will start off by shaving the throttle body for a cleaner look, get rid of the unneeded components. what about porting work? Quote Link to comment Share on other sites More sharing options...
mwilkinson Posted February 23, 2017 Share Posted February 23, 2017 (edited) If you look at the linked build thread by DanDan I think he covers some info about the modified stock manifold. http://www.mkivsupra.net/vbb/showthread.php?194439-Dan-s-Supra-Project/page12&highlight=Alcon+brakes The next page on the above link has pictures of the inside of the manifold. Edited February 23, 2017 by mwilkinson (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 23, 2017 Share Posted February 23, 2017 (edited) The plenum on a FI engine just flows air. It has to merely allow an equa flow both under N/A and boosted conditions with no substantial pressure drop. Where things become critical is in the ports, where a fuel wetted, far denser air has to flow without fuel separation, hence attention to surface finish and port shapes. The stock plenum *WILL* have been *PROPERLY* flow tested, both as a CAD and in use on a real engine. The aftermarket ones? Who the hell knows... Do you need an aftermarket one? A: I like the looks, they look the business, I don't care if the work better or worse than stock. You need one... B: I'd buy one if it improved power. Two ten quid pressure / vacuum meters off Ebay will tell you. One pre the throttle body, one on the plenum. If you see the one pre reading substantially higher thasn the one post the TB at peak torque or peak power RPM under boost, then you might benefit from a bigger bore TB. Too big though and throttle progression will go to pot, with the first bit of accelerator movement going from idle to full power, the rest doing nothing. You might even get a bad combination of too big a TB and a bad plenum design where lifting OFF the throttle a tad the engine makes more power. Disconcerting and a sure sign of the combo being wrong. Have I seen this on 2JZ-GTE's? Hell, sure, several times. You may need one, you need to test... Does a bigger diameter TB or bigger volume plenum add turbo lag? Unlikely, the sheer volume of air being moved in cubic feet is so huge it makes IC pipe volume and plenum volume only a tiny percentage of what the turbo puffs out under boost. I have never perceived an increase in lag due solely to a bigger volume plenum. But a bad plenum that gives uneven air distribution to the ports is bad, for sure. If one port gets more than its share of air that has to be run richer somehow. Short of measuring AFR on a cylinder per cylinder level all you end up doing is richening or weakening to get an overall correct AFR, and the ports that receive different amounts of air to the others may be running their cylinders rich or lean, and you won't know. Edited February 23, 2017 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
Krister Posted February 24, 2017 Share Posted February 24, 2017 Chris, have you any experience with twin chamber plenums? The audi 5 cylinder guys rave about them, but I'm yet to see them being adopted by Japanese car tuners. https://www.instagram.com/p/1TQqS4QsG6/ Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 24, 2017 Share Posted February 24, 2017 The N/A Supra engine already has one.... Quote Link to comment Share on other sites More sharing options...
Krister Posted February 24, 2017 Share Posted February 24, 2017 (edited) The N/A Supra engine already has one.... It's not a twin chamber as they are used in forced induction. A twin chamber intake manifold has a thin opening along side the whole manifold which creates an even flow to all intake ports. They are usually used in WRC rally cars IMSA cars etc.. You can buy a DIY kit from here: http://www.amwdynoservice.com/page25.php?view=productListPage&category=14 It's the same as in the Instagram photo I posted above. Edited February 24, 2017 by Krister (see edit history) Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted February 24, 2017 Share Posted February 24, 2017 As above, I thought the purpose of the n.a. intake was to act as a variable length intake, whereas the true twin chamber plenums as Krister has shown are for equalizing airflow in forced induction applications Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 24, 2017 Share Posted February 24, 2017 The Skoda plenum, for example, is designed to equalize air flow across all 4 cylinders under boost. the high velocity air will not favour changing direction into the first two ports, so the cross sectional area of the plenum is increased to lower air velocity. They spend weeks on dynos sacrificing dozens of engines getting all this right, and WRC cars are a bit "odd" in having a turbo restrictor, so they run relatively low RPM and try and maximize torque. Another reason for elaborate intake designs. Dual plenums with a solenoid valve to vary its volume like on an N/A Supra are all about pulling up peak torque at a favoured RPM band. Here#s the plenum I did for my 4AGE turbo engine, to similarly try to even air flow from its single TB Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted February 24, 2017 Share Posted February 24, 2017 So would individual throttle bodies render these twin chamber (forced induction) plenums moot? I fancy having a go at adapting a set of E46 M3 DBW ITB's to fit my car, although I assume it will be a lot of work and expensive for a minor gain. Quote Link to comment Share on other sites More sharing options...
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