987 Air Box Upgrade.

[edc]

Equally others have done the throttle body on standard airbox and shown a small improvement. Years ago I was sceptical of the 987 airbox. But the 550 shows it makes a difference and those using it as a mod have shown it makes a difference too. The 987 filter is much larger than the 986. I think the other important thing for the cone type filter is that they are always marketed as "free flow". Are they actually and can they actually pass more air? The actual data will be different for different filters of course. 

For your last question of just adding the 987 airbox, this is in essence the 550 spec and it is rated for more power than a standard late 986S. 

[phazed]

So the 550 uses the same throttle body?

[Patt]

yep, but a different connecting pipe.  IIRC the 987 angled one, rather than the perpendicular 986 style

[map]

41 minutes ago, Patt said:

yep, but a different connecting pipe.  IIRC the 987 angled one, rather than the perpendicular 986 style

Learn something every day - I thought the 550 ran a 74mm TB and Plenum. 

[edc]

550 is regular 68mm throttle body, MAF has different placement further along the intake pipe and as @Patt says the intake pipe is more curved similar to 987. 

[Patt]

I am sure it was the same size as a standard 986, just the different joining tube to the plenum.  

Years ago we were going to put the larger TB onto EDC's 550, but he gave up trying to get the right "t-piece"

[Patt]

1 minute ago, edc said:

550 is regular 68mm throttle body, MAF has different placement further along the intake pipe and as @Patt says the intake pipe is more curved similar to 987. 

Thanks ED, I thought that was the case.

[½cwt]

2 hours ago, Patt said:

I am sure it was the same size as a standard 986, just the different joining tube to the plenum.  

Years ago we were going to put the larger TB onto EDC's 550, but he gave up trying to get the right "t-piece"

Checking the parts cat, the TB is the same, but the intake for build code M091 ('50 years Spyder') has a 987 part numbered intake pipe, MAF and air box.

[edc]

3 hours ago, Patt said:

I am sure it was the same size as a standard 986, just the different joining tube to the plenum.  

Years ago we were going to put the larger TB onto EDC's 550, but he gave up trying to get the right "t-piece"

Apart from the pipe I still have all the bits in the garage despite moving house since! 

[edc]

1 hour ago, ½cwt said:

Checking the parts cat, the TB is the same, but the intake for build code M091 ('50 years Spyder') has a 987 part numbered intake pipe, MAF and air box.

Exactly and if you look back through the annals here @Berty987 was one of the first proponents of this mod on this forum and it was his at the time Planet-9 article that spawned these mods here. His was an early 987 and from recollection this has the "better" freer flowing manifolds compared to later 987 and he got up to circa 295bhp on the Dyno. 

My own 550 was not quite running quite right and is quite high mileage but still pulled circa 272bhp from I think just manifolds alone. If my memory is right it also had a loose spark plug on that run too. I'd speculate that with a slightly freer flowing exhaust and the TB it would be much closer albeit 987 also uses the 68mm throttle. The 987 intake manifold is quite different to the 986 so I expect some little ponies are in that too. 

[ATM]

On 4/5/2024 at 11:10 AM, edc said:

I think the other important thing for the cone type filter is that they are always marketed as "free flow". Are they actually and can they actually pass more air? The actual data will be different for different filters of course. 

 

The 981 uses cone filters. They're big and it has 2. One each side. This pic shows the size compared to some guy's hand

 

[phazed]

Having got the free flowing stainless swept manifolds, sports cat's and exhaust system fitted already.
I have a 987 airbox on the shelf to fit.
At this point, I suppose, I should go down the route of 987 manifolds, larger throttle body, Tee piece, and associated pipework.

In theory that would give me the most possible power without disturbing the engine itself.?

Did someone on this thread say they had some of these parts hanging around? If so, do they want to move it on?

My one concern would be if these upgrades just gave you a peak power output at the very top end but didn’t particularly do anything to the mid range torque.

Strangely after driving my 986 and 987 back to back, the 986 is definitely lacking in mid range torque although it fair sings at the top end! The most noticeable torque area is round the 2KRPM, which makes gentle, cruising around easy, the 987 (RS60) has that torque continuing, fairly linear like through the whole rev range.

[edc]

2 hours ago, ATM said:

The 981 uses cone filters. They're big and it has 2. One each side. This pic shows the size compared to some guy's hand

 

I'd wager the 987 air filter has more surface area than that single cone filter. You'd also not fit that easily in a 986 without leaving it exposed to sucking in hot air. 

[edc]

2 hours ago, phazed said:

Having got the free flowing stainless swept manifolds, sports cat's and exhaust system fitted already.
I have a 987 airbox on the shelf to fit.
At this point, I suppose, I should go down the route of 987 manifolds, larger throttle body, Tee piece, and associated pipework.

In theory that would give me the most possible power without disturbing the engine itself.?

Did someone on this thread say they had some of these parts hanging around? If so, do they want to move it on?

My one concern would be if these upgrades just gave you a peak power output at the very top end but didn’t particularly do anything to the mid range torque.

Strangely after driving my 986 and 987 back to back, the 986 is definitely lacking in mid range torque although it fair sings at the top end! The most noticeable torque area is round the 2KRPM, which makes gentle, cruising around easy, the 987 (RS60) has that torque continuing, fairly linear like through the whole rev range.

I've posted my plots before but I got a little more from circa 3.5k rpm and the delta getting bigger through to 7k rpm. 

[ATM]

9 minutes ago, edc said:

I'd wager the 987 air filter has more surface area than that single cone filter. You'd also not fit that easily in a 986 without leaving it exposed to sucking in hot air. 

Yeah that's my thought. The so called high flow cones have a tiny surface area of filter. They may be higher flow than a flat panel which is roughly the same size but if you compare a smallish cone to a massive air box holding a flat filter it's not even the same ball game. 

[bally4563]

As a retrofit with everything installed, expect once fitted , if at the boozer that night someone asked you what do you do for a living  , and you said you wrestle Tigers , they would believe you…. Ask me how I know !! Done it for myself, would I do it for anyone else …. The answer would start with Fek and off !!

[Nitro V8]

4 hours ago, phazed said:

Having got the free flowing stainless swept manifolds, sports cat's and exhaust system fitted already.
I have a 987 airbox on the shelf to fit.
At this point, I suppose, I should go down the route of 987 manifolds, larger throttle body, Tee piece, and associated pipework.

In theory that would give me the most possible power without disturbing the engine itself.?

Did someone on this thread say they had some of these parts hanging around? If so, do they want to move it on?

My one concern would be if these upgrades just gave you a peak power output at the very top end but didn’t particularly do anything to the mid range torque.

Strangely after driving my 986 and 987 back to back, the 986 is definitely lacking in mid range torque although it fair sings at the top end! The most noticeable torque area is round the 2KRPM, which makes gentle, cruising around easy, the 987 (RS60) has that torque continuing, fairly linear like through the whole rev range.

Hi @phazed

   I have a brand new 74mm tb and a brand new with gasket 996 T/plenum to suit if you are interested. I also have various pipe work and a modified 987 airbox with maf holder and maf.

let me know if interested.

[phazed]

Will try and p.m. you. Will clear my inbox first as it says it is full so hopefully expect a message soon!

[phazed]

Can someone show me how to delete my previous messages as I cannot use the PM facility until that is done. Thank you.

[BBB]

4 minutes ago, phazed said:

Can someone show me how to delete my previous messages as I cannot use the PM facility until that is done. Thank you.

Click on your message icon (top right of screen, looks like an envelope). Then you’ll see the expanded view of messages on the right of screen and a smaller list of messages on the left, with little empty “select” squares. Click one (or multiple of those) and you’ll get a pop-up dialogue box, with delete as one of the options.
 

 

[½cwt]

14 minutes ago, phazed said:

Can someone show me how to delete my previous messages as I cannot use the PM facility until that is done. Thank you.

May be if you think the forum is good value, become a Site Contributor for just for £10 towards running cost of the site, then you get a much bigger mail box and you can edit your posts for longer if required, just a coupe of bonuses.. 😉

[phazed]

32 minutes ago, ½cwt said:

May be if you think the forum is good value, become a Site Contributor for just for £10 towards running cost of the site, then you get a much bigger mail box and you can edit your posts for longer if required, just a coupe of bonuses.. 😉

Sounds like a good idea. I didn’t know anything about that! Point me in the right direction please.

[phazed]

26 minutes ago, phazed said:

Sounds like a good idea. I didn’t know anything about that! Point me in the right direction please.

Done.

[phazed]

3 hours ago, Nitro V8 said:

Hi @phazed

   I have a brand new 74mm tb and a brand new with gasket 996 T/plenum to suit if you are interested. I also have various pipe work and a modified 987 airbox with maf holder and maf.

let me know if interested.

Message sent...

[½cwt]

3 hours ago, phazed said:

Sounds like a good idea. I didn’t know anything about that! Point me in the right direction please.

I see you got there unassisted, but for the benefit of others who may wish to do the same, select Store just under the advert banner at the top of the home page.