edc Posted February 15 Report Share Posted February 15 996 plenum or air intake distributor tube is showing as about £50 now. Was £35 plus a few years ago. Quote Link to comment Share on other sites More sharing options...
Nitro V8 Posted February 15 Report Share Posted February 15 I’m still not sure about the 74mm and 996/7 plenum. I still have not seen a before and after Dyno showing an improvement. The only evidence I have is from Wayne at chip wizards who says don’t bother, Marty Wild thread that says “no gain” and an engine builder/tuner who did the maths and said maybe small gain in hp (2-5) and loss in torque below 5k due to air flow velocity slowing down. Still pondering. Quote Link to comment Share on other sites More sharing options...
Terryg Posted February 15 Report Share Posted February 15 I did tubular headers and 200 cell cats and that made a difference. I did the TB and noticed nothing really, maybe it needed the 987 airbox and a remap, I don't know. Quote Link to comment Share on other sites More sharing options...
edc Posted February 15 Report Share Posted February 15 My Dyno showed a gain but the link in my threads are dead now. 1 Quote Link to comment Share on other sites More sharing options...
Nitro V8 Posted February 16 Report Share Posted February 16 9 hours ago, edc said: My Dyno showed a gain but the link in my threads are dead now. @edc Do you still have the Dyno plots and can you re post them? Or can you remember the detail of what the actual gain was and where it was in the rev range? Cheers Quote Link to comment Share on other sites More sharing options...
phazed Posted February 16 Author Report Share Posted February 16 It seems that a lot of people are saying that there is practically no gain at all from standard, and there are a few that say that there is a small gain, but as yet it would be good to see actual results. Happy to do the mods if it is going to be beneficial. As I may have mentioned before, when doing a lot of upgrades to my old TVR, small gains have not been noticeable, you need something like a 30–50 BHP gain to make it really noticeable. If it just gives 10 BHP, cost hundreds of pounds and creates a lot of work, just in that respect it isn’t worth it. Very happy to be proved wrong. 1 Quote Link to comment Share on other sites More sharing options...
edc Posted February 16 Report Share Posted February 16 8 hours ago, Nitro V8 said: @edc Do you still have the Dyno plots and can you re post them? Or can you remember the detail of what the actual gain was and where it was in the rev range? Cheers Here's a couple of relevant old posts. Pick your way through if you haven't already Dyno plots seems to show here https://www.BoXa.net/topic/53075-blue-boxster-s-with-18-sport-classics/page/11/ 1 Quote Link to comment Share on other sites More sharing options...
Nitro V8 Posted February 16 Report Share Posted February 16 @edc Thank you Quote Link to comment Share on other sites More sharing options...
Boxsum Posted February 16 Report Share Posted February 16 6 hours ago, edc said: Here's a couple of relevant old posts. Pick your way through if you haven't already Dyno plots seems to show here https://www.BoXa.net/topic/53075-blue-boxster-s-with-18-sport-classics/page/11/ The manifolds seemed a good investment per bhp 👍 Ive fitted the euro cup gt headers but never had a dyno run to see the difference 1 Quote Link to comment Share on other sites More sharing options...
bally4563 Posted February 16 Report Share Posted February 16 From memory on my old 986 S I did all the mods , manifolds TB 987 air box etc , what I would say not necessarily more powerful but the marginal improvement in torque was noticeable as in it made the delivery more linear with no flat spots certainly around the 4k rpm and upwards 1 Quote Link to comment Share on other sites More sharing options...
½cwt Posted February 16 Report Share Posted February 16 People talk about bhp, but what you notice or 'demand' with the throttle is lbft or torque. It is why turbos are so effective as they give loads of both and why it is so difficult to get good torque increases in a normally aspirated engine. A 2 litre turbo running at 1bar or 15psi boost is effectively a 4 litre engine (give or take some compression ratio in the cylinders). 1 Quote Link to comment Share on other sites More sharing options...
phazed Posted February 16 Author Report Share Posted February 16 Yep. My old track day Skoda was a box standard 1.8T engine with a remap and a sports exhaust. An easy 245bhp and 310 ft lb of torque. 1 Quote Link to comment Share on other sites More sharing options...
Boxsum Posted February 16 Report Share Posted February 16 29 minutes ago, ½cwt said: People talk about bhp, but what you notice or 'demand' with the throttle is lbft or torque. It is why turbos are so effective as they give loads of both and why it is so difficult to get good torque increases in a normally aspirated engine. A 2 litre turbo running at 1bar or 15psi boost is effectively a 4 litre engine (give or take some compression ratio in the cylinders). It’s interesting that many people disliked the later turbo engined boxsters🧐 1 Quote Link to comment Share on other sites More sharing options...
Nitro V8 Posted February 17 Report Share Posted February 17 5 hours ago, Boxsum said: It’s interesting that many people disliked the later turbo engined boxsters🧐 I’ve never driven a 718 turbo Boxster but I know in general I prefer a n/a car. All the favourite cars I have owned have been n/a. Turbos can give massive power but there is nothing like ringing out a great high revving n/a car and enjoying the increasing crescendo of noise as the revs rise to a peak. The dislike for the 718 turbo boxster I think is as much to do with having four cylinders as opposed to six? Quote Link to comment Share on other sites More sharing options...
Terryg Posted February 17 Report Share Posted February 17 Reading @edc thread, I totally agree, the headers and in my case 200 cell cats made the most noticeable diference, the car just revved way quicker and felt so much better. The other changes may well have delivered extra power but the difference wasnot noticeable. Having said that, I enjoyed the journey, would do it all again and would love to have that car back. 1 Quote Link to comment Share on other sites More sharing options...
½cwt Posted February 17 Report Share Posted February 17 (edited) 7 hours ago, Boxsum said: It’s interesting that many people disliked the later turbo engined boxsters🧐 I was not advocating for the 4 pot turbo Boxster... Just observing that the cost/return ratio for tuning a n/a engine is high. That said if there had never been a 6 pot n/a Boxster and the 4 pot turbo came along people would probably love it. I've not driven one but I imagine the performance envelope is pretty good but the characteristics of that envelope are likely quite different to a n/a engined one. Besides its all about the emissions and fuel consumption these days, otherwise why would Porsche have spent the money developing that engine? As @phazed say with his figures, +20% on a turbo is easy, +5% on n/a takes time, effort, a lot more parts and more money. Edited February 17 by ½cwt 1 Quote Link to comment Share on other sites More sharing options...
Jonttt Posted February 17 Report Share Posted February 17 Chasing performance on a n/a boxster is just not good vfm / a waste of time. You would be far better spending your money on suspension / driving lessons / petrol the 4 pot FI engines are fine to those who never appreciated the 6 cylinder NA engines. However all arguments over their relative merits stopped when porsche backtracked and fitted the n/a 6 cylinder engines to the top of the range models I had a 2.5 fully loaded 718 for 3 days as a loaner and took it back early on day 2, i had zero interest in it as a porsche, which is ironic given i love my taycan Quote Link to comment Share on other sites More sharing options...
Terryg Posted February 17 Report Share Posted February 17 Chasing an improved driving experience isn't a waste of time though, that can be achieved and for a relatively small outlay. Quote Link to comment Share on other sites More sharing options...
Nitro V8 Posted February 18 Report Share Posted February 18 8 hours ago, Terryg said: Chasing an improved driving experience isn't a waste of time though, that can be achieved and for a relatively small outlay. and for the enjoyment of us car fiddling fanatics! 1 Quote Link to comment Share on other sites More sharing options...
phazed Posted April 4 Author Report Share Posted April 4 I was just having a browse on YouTube looking at the various airbox, or the complete removal of airbox and the fitting of a shield and a cone air filter, how to’s and came across this which was surprising and enlightening. For those that can’t wait till the end .Free flowing exhaust gives more power. Ditching the 986 airbox, fitting a more free flowing filter in an enclosed box type area and fitting a larger throttle body, and the ancillaries that go with it which in theory should work well actually makes you lose power! well, there’s a few quid saved! I wonder if they had just fitted the 987 airbox and left the throttlebody standard whether that would have given an improvement? Quote Link to comment Share on other sites More sharing options...
ATM Posted April 4 Report Share Posted April 4 I've read elsewhere that the IPD t or y piece replacement thing loses power on the 996. So I'd be curious to know if you can use the fabspeed air box replacement without the IPD. Quote Link to comment Share on other sites More sharing options...
map Posted April 5 Report Share Posted April 5 7 hours ago, phazed said: Ditching the 986 airbox, fitting a more free flowing filter in an enclosed box type area and fitting a larger throttle body, and the ancillaries that go with it which in theory should work well actually makes you lose power! From experience: Those silicon hoses cannot hold the vacuum:ambient air pressure differential created by the engine from early mid range up. The hose simply collapses - I know this because I watched it happen to my car the first time it was run with this type of config. Which is why my install uses metal ducting from maf-throttle body. Having watched the video they do not appear to have remapped the ECU. Nor was there any mention of driving the car on the road far enough to allow the ECU to adjust to the mechanical alterations. My 3.2 with the equivalent mechanical changes (as described in my thread) and a remap hit 290bhp on Parr’s hub dyno. As always the Devil’s in the Details. 1 Quote Link to comment Share on other sites More sharing options...
phazed Posted April 5 Author Report Share Posted April 5 All very good points Map. Quote Link to comment Share on other sites More sharing options...
map Posted April 5 Report Share Posted April 5 21 minutes ago, phazed said: All very good points Map. 👍 Most silicon hoses seem to be aimed at Forced Induction engines where they hold positive pressure rather than withstanding negative/vacuum. On my car the collapse almost closed the hose - no point having a larger TB/Plenum if the feed is so compromised. In terms of the video - the other standout for me was the cone filter which seemed quite small. On my car we designed the air box to hold a 400bhp cone filter which gives plenty of headroom. Quote Link to comment Share on other sites More sharing options...
phazed Posted April 5 Author Report Share Posted April 5 Yes, I see your point about the filter. I did the same with my last Track car. K and N designed a surprisingly large cone filter for my 250 BHP car. Quote Link to comment Share on other sites More sharing options...
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