Nitro V8

Well after some time I have now gathered all the bits together to do the 74mm tb conversion.

I will detail all the components and photo all as I go along as it maybe helpful to others.

I unfortunately won’t be carrying out the work for some while as I am currently recovering from an op on a ruptured biceps.

The areas I’m unsure about is are as follows.

1) I have got hold of a 987 airbox but unsure whether to fit it or not as I know it is difficult. Is the 986 airbox restrictive enough with the 74mm tb to warrant fitting the 987 one? Does anyone have any insight into this?

2) If I go the 987 route should I use the 987 maf holder/tube as I have read here and on the US 986forum that the ECU will require a re map to get fuelling correctly and prevent a cel? Again does anyone have experience of this? If utilising the existing 986 maf holder/tube will this now be restrictive?

Thank you.

1 hour ago, Menoporsche said:

Never heard of one but they are cheap enough from a breaker to experiment for yourself?

Yes that is the plan but just wondered what was already available if anything. 

Does any aftermarket company sell a modified rear number/valance that leaves the exhaust/gearbox exposed to view?

Ignore the above, I’ve found the answer it is 3” 76mm. So it goes down from 76mm at the maf to 68mm at the throttle body.

Interestingly the 996 maf tube is 31/2” 90mm. Goes down from 90mm at the maf to 74mm at the throttle body.

I wonder if that is to accelerate the airflow?

I therefore wonder if we are doing the 74mm tb and plenum conversion on our 986’s should we be using a 90mm maf tube?

Hopefully last question!

Does anybody know the od of the maf tube where the new silicone elbow will join up to?

Just so I can get exact size fit.

Thank you

Thank you for all the replies.

   Hopefully when I do mine I can take plenty of photo's and maybe we can put it in a "how to" section so others can benefit from all the good work you guys have done.

Cheers

A few more questions please.

1) I found edc parts list and it says 12” Ali pipe 83mm id. I think this should be od as that is how they tend to be sold and it matches the id of the silicone elbows?

2) I can only find 80mm od Ali tube (auto silicone hoses) so is that ok?

3) They sell a beaded version so is 12” accurate enough to order beaded or did it need cutting down?

4) There is a choice of id for the silicone elbows of 80mm or 83mm. edc parts description says 83mm. Would 80mm be better to match Ali tube or will this struggle going over the 74mm throttle body or maf housing? If the internal of the tb is 74mm I can only think the wall thickness would be a couple of mm so 78mm max od? Is the maf housing tight for a 80mm id silicone hose?

Thank you

Patt, edc and map.

     Thank you all very much for the guidance and photo's.

A great help. 👍

That's great, thank you!

Are the 74mm 911 plenum outlets the same size as the 986 68mm plenum's or is there a step in size?

Cheers

8 hours ago, edc said:

I've posted parts and price and pics before. 996 plenum was about £35.

I've still got the bits I think in my garage to do this second time around on what was my new to me 550 coming up 10 years ago

Hi 

   I'm struggling finding any photo's of the install so I can understand the pipework lengths etc. The photo's in your thread are no longer live. Does anybody have any photo's that may help?

Thank you in advance

P.S. 

2 hours ago, Patt said:

If you research, you'll find a list of cars and the Bosch part numbers too.

It's much cheaper to use the 996 factory plenum, but it's your choice

Thank’s for pointing me in the right direction. I will have a read up.

Cheers

Has anybody tried an 82mm tb with an adaptor down to a 78mm plenum?

would this have any benefit at all over the 78mm tb?

Just a thought as I have seen a cheapish 82 for sale.

47 minutes ago, Lonewolfgjp said:

Hi there 

I think you have got a few options, I used the one off the gen1 Cayman 3.4 but you can use the 996 one as well. There maybe some others you can use as well 👍

Hi. That’s great, thank you.

Hi all

    Thinking of doing the 74mm tb conversion on my 2003 3.2.

I will probably use the Uniwerks carbon plenum/kit.

My question is which 74mm tb should I use? Does it matter if it is from a 996 or a 987 or any other model. Or is there a specific one I should get?

Thank you

I’ve got the Topgear back box on mine and like others above it sounds great when going for it but does drone on a cruise. I think they are all pretty much the same of that type of design. It does look good with the meshed plates under the boxes and seems well made.

I bought it cheap and was dissuaded from fitting it originally by Lee at Cotswold as he said it would drone. However my oem back box seems split so had Cotswold put it on whilst for the interim.

12 hours ago, fizz said:

I've got one of those in the civic and its very good. Where in the boxster you placed it? Right side of the windscreen? 

As much as i fancy getting one that sits in the air vents, i have actually found the windscreen mounted ones good for recording video whilst driving on the mobile. 

I placed it to the left of the dashboard above the central vents. I’ll take a photo when my car is back from having a new clutch fitted. 

Hi

    I bought this one and stuck to the windscreen 6 months ago using the suction cup. It is still on, even in this heat!

https://www.amazon.co.uk/Beikell-Adjustable-Holder-Cradle-Release-Black/dp/B0792Z94FF?pd_rd_w=HaIpO&content-id=amzn1.sym.e4f17dd8-9383-42c6-acc3-c75af35f1776&pf_rd_p=e4f17dd8-9383-42c6-acc3-c75af35f1776&pf_rd_r=P222BB7ZEZG3EGDNXFWE&pd_rd_wg=ZJh2o&pd_rd_r=24355b93-39fb-43e8-84fa-2f0c47df795a&pd_rd_i=B0792Z94FF&psc=1&ref_=pd_bap_d_grid_rp_0_32_t

Hi all

   Received my Calendar this morning. Very very nice!

Well done all those involved in producing it.

Shame I can’t actually post in the Calendar thread.

Great thanks

Thank you

Hi

    I have paid for a calendar but cannot see my name on the list.

Also I cannot post in the Calendar thread?

Thank you

They have come up well.

Another job on my list!