LingLong Posted May 28, 2016 Share Posted May 28, 2016 Hey guys! Im new to the forum and working on cars in general. My AE86 Levin has recently been stolen and luckily recovered. Anyway, a rebuild is being planned and I am wanting to use this time to upgrade bits and pieces etc. Something that has been on my list is to upgrade the current intake setup as it can definitely be improved upon. Currently a 20v head with itbs and crude plenum. My question for you experienced 4AGTE folk is, do I keep the itb setup and get a new plenum, or do I ditch itbs and go for a single throttle? For my build I am aiming for good response and a decent power range, Im not looking for big top end power numbers and would rather have more useable power throughout. I would like to know with peoples experience the pros and cons of either itb or single tb? To keep the itb setup would probably be cheaper and easier as all i have to do is bolt another one on. But in the long run is tuning and maintaining an itb setup a big hassle? I seem to hear that they are touchy and high maintenance but can pay off if you are after that little bit more performance. If I were to go single throttle I would probably just bite the bullet and get an MRP plenum which is pricey, plus extra expenses of top feed injectors and whatever else is needed. Will this be a lower maintenance setup, can it perform better than itbs? who knows? Not me!!!Engine bay pic https://www.instagram.com/p/BF78vdrnMcc/?taken-by=ken_ola_oil&hl=en 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 28, 2016 Share Posted May 28, 2016 Stick with the itb's. will have to be a pretty good single throttle setup, to make any gains over the stock setup. have the benefit of being able to move the power around by changing trumpet length on itb setup Quote Link to comment Share on other sites More sharing options...
1Gesus Posted May 28, 2016 Share Posted May 28, 2016 If I had a 4age id probably go bankrupt spending all my money here > http://www.mrpltd.co.nz/product/386/4age-20v-plenum.html Quote Link to comment Share on other sites More sharing options...
Tim.a Posted May 29, 2016 Share Posted May 29, 2016 I am running a gtir plenum with a laser cut adapter plate to suit the 20v. Havent run it yet but seems like a few guys have done it. looks quite tidy and factory as well. Heres a picture of someone thats done it because i couldnt be bothered uploading mine haha. 1 Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted May 30, 2016 Share Posted May 30, 2016 chap at work has indeed just done an intake using gtir plenum cover. worked out pretty good, unless you plan on messing around with trumpet lengths, as i dont think there is room at the rear. But If I was building one, I would do the same mod I would say Quote Link to comment Share on other sites More sharing options...
LingLong Posted May 30, 2016 Author Share Posted May 30, 2016 Thanks for your replies, It looks like sticking with the itb setup seems to be the most practical but I am still considering a single throttle, I must admit I think stb looks much cleaner. I am wondering if anyone has any experience with running both itb and stb on their turbo setups? was there really any noticeable difference between the two?? I guess a comparison would be between 16v 4age turbos vs 20v 4age turbos with itb. Although they are possibly quite different. Best inside info would be from someone who has run both itb and stb on the same setup! Here is a fap pic of the possible single throttle setup I would possibly go for.. So clean, love how beefy it looks too https://www.instagram.com/p/BF-mscnnMVM/?taken-by=ken_ola_oilI am curious if, (with single throttle) on throttle and off throttle response is really going to be affected noticeably at 14 psi of boost and high rpm engine braking. Are there any calculators I can use to see what the actual difference in time there will be to fill and consume the volume of a larger single throttle plenum. If it is some tiny amount of time then I would consider the benefit of itb response to be negligible!Another fiscal question... Would the sound of the engine change if I went stb? Just curious!I have been hunting around on RB26 forums but they seem to be hunting for big power, not many people talking about street/circuit applications and nobody seems to have a direct comparison of both. Quote Link to comment Share on other sites More sharing options...
Roman Posted May 30, 2016 Share Posted May 30, 2016 The time difference of response is bugger all. As an example. A 2000cc 4cyl 4 stroke engine (if non turbo and 100% VE) inhales 1000 litres of air per 1000rpm. So 7000rpm = 7000litres per minute. 2 litre plenum = under 20 milliseconds to empty. A 20 litre plenum, which would be rediculous, (size of 10 milk bottles stuffed in your engine bay somewhere) would still only be 200 milliseconds.A 1.6 litre engine will be 0.8x the times listed above.Human reaction time if you're wired on coffee is just under 1/3rd of a second, (300 milliseconds). You're not going to notice any difference in sound, because all of the sound waves are happening between the plenum and turbo outlet rather than exposed to atmosphere with NA car.Single throttle will be easier to tune as you get a more stable MAP signal, personally if I was going ITB turbo I would fit a MAF Sensor if off boost drivability etc is of concern. 2 Quote Link to comment Share on other sites More sharing options...
Spencer Posted May 30, 2016 Share Posted May 30, 2016 You are overthinking this whole thing, just use what it has (ITBs) and make a plenum. You can bang up a plenum out of steel if needed, nicer (but less DIY friendly) obviously out of alloy. Job done. 2 Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted May 30, 2016 Share Posted May 30, 2016 Mega tech post I fell this would be better explained............... in a graph 4 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted May 30, 2016 Share Posted May 30, 2016 Thanks for your replies, It looks like sticking with the itb setup seems to be the most practical but I am still considering a single throttle, I must admit I think stb looks much cleaner. I am wondering if anyone has any experience with running both itb and stb on their turbo setups? was there really any noticeable difference between the two?? I guess a comparison would be between 16v 4age turbos vs 20v 4age turbos with itb. Although they are possibly quite different. Best inside info would be from someone who has run both itb and stb on the same setup! Here is a fap pic of the possible single throttle setup I would possibly go for.. So clean, love how beefy it looks too https://www.instagram.com/p/BF-mscnnMVM/?taken-by=ken_ola_oil I am curious if, (with single throttle) on throttle and off throttle response is really going to be affected noticeably at 14 psi of boost and high rpm engine braking. Are there any calculators I can use to see what the actual difference in time there will be to fill and consume the volume of a larger single throttle plenum. If it is some tiny amount of time then I would consider the benefit of itb response to be negligible! Another fiscal question... Would the sound of the engine change if I went stb? Just curious! I have been hunting around on RB26 forums but they seem to be hunting for big power, not many people talking about street/circuit applications and nobody seems to have a direct comparison of both. Why not check out the sr20 forums. They use single and quad throttles on the same basic motor and I bet you can find heaps of threads about it. As David has said- the time taken to empty the plenum is SFA...but even if it WAS a significant difference, who cares. Ditto with the engine sound thing. Once the motors running you won't care two shits what it comparatively sounds like. Basically, don't end up like ME stressing over numbers on a piece of paper. It's a downward spiral into huge unfinished project territory and I owuldnt wish it upon anyone Quote Link to comment Share on other sites More sharing options...
Stu Posted May 30, 2016 Share Posted May 30, 2016 Just run with what you want it to look like - there's very little in it. If you like the look of a single and have the money to buy one or time to make one, go for it. If you want to keep the quads then just get a new plenum as your current one needs to be run over by a bus. Changing the turbo will have more of an effect than changing the inlet. Quote Link to comment Share on other sites More sharing options...
LingLong Posted May 31, 2016 Author Share Posted May 31, 2016 I think everyone is on the money. Ive been nutting it out way too much haha. Im just gonna do whats easiest and most cost effcetive for me atm and keep the itbs. Some good advice from everyone. Time to get on with it Quote Link to comment Share on other sites More sharing options...
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