joe blo Posted August 28, 2014 Share Posted August 28, 2014 Hey mates I'm just looking at the dyno sheet I got with this beast. I'm wondering about the boost curve. Does it show that it doesn't make full boost until 7500 rpm? I would expect it to make that at worst case 5700rpm then the line to stay flat till max rpm. It's a gt35 .82 rear on a rb20. Garrett turbo. China stainless manifold. 38mm wastegate screamer pipe. Boost controller is a turbo smart dual stage manual one. No idea what spring is in wastegate Looking for some ideas on if that's how it shud be or if something's goin on with setup. I understand its not the ideal size turbo but that's what's on it. Il live with it Thanks mates Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/ Share on other sites More sharing options...
scotty nm35 Posted August 28, 2014 Share Posted August 28, 2014 The goal is area under the curve, not over it. 3 Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376434 Share on other sites More sharing options...
joe blo Posted August 28, 2014 Author Share Posted August 28, 2014 (edited) Wat u mean? Edited August 28, 2014 by joe blo Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376436 Share on other sites More sharing options...
MrStabby Posted August 28, 2014 Share Posted August 28, 2014 Have a look through the RB20 Dyno sticky thread. For example, the dyno sheet on the top of the last page shows the sort of shape you should be aiming for manifold pressure (boost). I'd guess your setup is always going to be horrible with a turbo that big. Suggest you change your mind about living with it. You want to enjoy driving your car don't you? Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376439 Share on other sites More sharing options...
joe blo Posted August 28, 2014 Author Share Posted August 28, 2014 (edited) Yea I've seen a lot of dyno sheets on there. I believe it should be as I suggested and reach full boost at a certain point in the 5000rpm range and hold it but want to confirm something may be up with mine and if something isn't right suggest what is causing it. Edited August 28, 2014 by joe blo Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376441 Share on other sites More sharing options...
scotty nm35 Posted August 28, 2014 Share Posted August 28, 2014 The turbo is too big, and the .82 housing is more suited to a 3L engine. A stock RB25 turbo can make that power, and come on by 3k on a 2L. It could make bulk KW if you were willing to rev it to 12k and make use of that amount of airflow. (porting heads, massive cams etc.) Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376445 Share on other sites More sharing options...
Dose Pipe Sutututu Posted August 28, 2014 Share Posted August 28, 2014 Wow, datlag Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376492 Share on other sites More sharing options...
Ben C34 Posted August 28, 2014 Share Posted August 28, 2014 If that's a genuine g35 you could (should) sell it and buy a hypergear turbo. Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376509 Share on other sites More sharing options...
joe blo Posted August 28, 2014 Author Share Posted August 28, 2014 So are you saying that the boost curve is correct? Full boost at 7500 rpm. Mainly just looking for the answers to what I asked Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376511 Share on other sites More sharing options...
joe blo Posted August 28, 2014 Author Share Posted August 28, 2014 Essentially it should perform similar to this one. http://m.youtube.com/watch?v=WF5iflTiyTs Which I dont mind Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376514 Share on other sites More sharing options...
Lithium Posted August 28, 2014 Share Posted August 28, 2014 Yes, the peak boost is at 7500rpm but that's not so much a factor of turbo lag as it is boost control - its boost creeping which is why it keeps climbing and ending up at it's highest there. Looks like the gate is opening at around 6000rpm, which is closer to your expectations and I'd say is probably more or less what you're going to get on an RB20. 1 Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376516 Share on other sites More sharing options...
Lithium Posted August 28, 2014 Share Posted August 28, 2014 Yes, the peak boost is at 7500rpm but that's not so much a factor of turbo lag as it is boost control - its boost creeping which is why it keeps climbing and ending up at it's highest there. Looks like the gate is opening at around 6000rpm, which is closer to your expectations and I'd say is probably more or less what you're going to get on an RB20. Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376519 Share on other sites More sharing options...
joe blo Posted August 28, 2014 Author Share Posted August 28, 2014 Yea I did consider it could be boost creep but I thought that if it could hold the 12 psi setting fairly well it should be able to control 21 psi. If I put a spring closer to 21 psi in the wastegate could that make it better? Could probably assume the current spring is below 12 psi Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376533 Share on other sites More sharing options...
scotty nm35 Posted August 28, 2014 Share Posted August 28, 2014 That will increase the boost, you should hit 21psi by 10k or so. An electronic boost controller may help with the boost curve, but a heavier spring will definitely be required in the wastegate. Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376539 Share on other sites More sharing options...
KiwiRS4T Posted August 28, 2014 Share Posted August 28, 2014 Your turbo is too big and your wastegate probably too small. You could fiddle with it but better to get another turbo. Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376542 Share on other sites More sharing options...
Dose Pipe Sutututu Posted August 28, 2014 Share Posted August 28, 2014 sell that turbo, and just buy a high flowed R33 turbo for your motor... would run better, would fry tyres better Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376557 Share on other sites More sharing options...
bcozican Posted August 28, 2014 Share Posted August 28, 2014 as said totally wrong setup so 7500 would be correct to give you an example I ran an rb22 with gtx3076 with 0.82 tial 44 Vipec 88 and e85 with basically everything you can get for that setup (cams dialled in etc) and had full boost at 5200 as all said above get rid of that turbo its never going to work Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376588 Share on other sites More sharing options...
Dose Pipe Sutututu Posted August 28, 2014 Share Posted August 28, 2014 even that turbo on a stock RB25DET with VCT would still be a bucket of lag 1 Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376605 Share on other sites More sharing options...
joe blo Posted August 28, 2014 Author Share Posted August 28, 2014 Tru. Well if that's the best I'm gunna get without major changes il just leave it. Reasonably happy with it. Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376617 Share on other sites More sharing options...
Dose Pipe Sutututu Posted August 28, 2014 Share Posted August 28, 2014 food for thought (ignore if you wish). Sell turbo Sell manifold Sell gate then buy a brand new hypergear highflow stock manifold spend all leftover cash on hookers and cocaine and whatever is left on tyres 1 Link to comment https://www.sau.com.au/forums/topic/447367-rb20-gt35-dyno-graph-boost-curve/#findComment-7376621 Share on other sites More sharing options...
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