46 replies to this topic

[liirge]

I'm currently building a fast 998, click on my sig for some ideas.

Philip, thats a very nice spec, it will be nice and torquey, and very smooth to drive!

[PhilipGCaldwell]

I'm currently building a fast 998, click on my sig for some ideas.

Philip, thats a very nice spec, it will be nice and torquey, and very smooth to drive!

haha, thanks liirge, just looked through ure proj thread, love the retro look I pretty much am after the same engine spec as u (im not strippin the engine completely though, keeping the same pistons and bottom end)

Im gonna get that swiftune kit aswell, the one with the duplex vernier and oil pump. bit pricey but a must i think, how did u go on with fitting it? People seem to rave about that cam

[liirge]

Fitted a dream no problem, just make sure you clean up the camshaft and the cam followers. The oil pump was all good, and i have primed it with assembly lube. duplex kit is really good quality, and the vernier makes it so easy to get the cam timing done (protractor provided in the kit). just make sure you have a DTI to time the cam in properly.
The SW5-07 is a fantastic cam, with very good driveability, however i have heard that it really isn't savage enough..i believe Shiftyseamus on here has one fitted to a 998, so try and PM him for info on the cam. I went for the SW10-07 as it's only a toy, so the no power low down wont affect me to much.

[huw_jenks]

In David Vizards book 'Tuning the A Series...' he gives a list of bolt on or other mods for all the different A series engines, and what order they should be done in. Stage One is first (hence the name!) to get the engine breathing better, then I think it goes;

Cylinder head
Carb(s)
Camshft and rockers
Electronic ignition (being least important).

Also worth studying the chapters about flowing the carb and inlet manifold. A couple of hours with a Dremel or file can get a single SU flowing as much mixture as a carb the next size up! Most stage one kits come with a K&N cone, which isn't much use without a ram pipe or stub stack inside. If you have standard airbox with a K&N element inside, try drilling a few big holes on the front to get more cold air in.

And I also agree with Pooky, best way to improve acceleration and fuel consumption is to shed weight!

[l_jonez]

i got a sw5-07 in my fast road 998 ( 12g40 head, rebore etc etc) and im pretty disapointed with it, i'll probably be changing it for some thing a bit hotter soon

[liirge]

If you are dissapointed in the SW5, maybe you were expecting too much from it, look at the below table of camshafts around the same area...
Camshaft, Duration and then the Lift (mm) on the far right.



848/998 A+ Leyland 230/240 6.35 6

Cooper 998 BMC 230/252 6.35 6.35

SW5 Swiftune 244/244 7.14 7.14

MD256 Kent 254/254 6.66 6.66

Cooper S BMC 240/252 6.35 6.35

MD266 Kent 260/270 6.68 6.85

997 Cooper BMC 252/252 6.35 6.35

Edited by liirge, 29 April 2010 - 05:18 PM.

[cap'n crunch]

Which is why in my 998 build i am going for a Kent 246

MD246 Kent 252/252 7.23 7.23


and liirge if you are mentioning downdraught carbs in reference to the 28/36 Weber, on mine no modifications were/are needed to make it fit under the bonnet.

[liirge]

Which is why in my 998 build i am going for a Kent 246

MD246 Kent 252/252 7.23 7.23


and liirge if you are mentioning downdraught carbs in reference to the 28/36 Weber, on mine no modifications were/are needed to make it fit under the bonnet.

What kind of Trumpets and filter are you running on that? also wondered if there's a better one, after doing some more research the 28/36 does not flow as much as twin SU's (HS4's).

[cap'n crunch]

No Trumpets, just a K&N Oval Filter which i think is 45mm high.

eh? does not flow as much? the 28/36 flows much better than a HS4. If you check the test vizard has done the 28/36 is far ahead (remember the 28/36 has changable venturis)

Edited by cap'n crunch, 29 April 2010 - 07:24 PM.

[liirge]

I will investigate further..i was talking about Twin Hs4's not just a single one!

[cap'n crunch]

It would make no difference whether it was single or twin. Only one is flowing at any time. Like a webber only one barrel is flowing at any time you cannot add them together.

The SU (or webber barrell) which is not directly inline with the cylinder on its intake stroke is adding no extra air flow.

Edited by cap'n crunch, 29 April 2010 - 07:35 PM.

[liirge]

yeah, sorry i was having a bit of a blonde moment!
just double checked my flow figures, and your right the SU is 142 and the 28/36 is 225....hmmm
Does she have that induction roar that side draught webers have.

Edited by liirge, 29 April 2010 - 07:38 PM.

[cap'n crunch]

But Twin SU's have a prefectly straight run to the cylinder head, where as the 28/36 has more angles to negotiate.

It's all swings and roundabouts but i know which one I would chose

[liirge]

Yeah that was another thing i was considering..so have you had any issues with your carb? as they're not the most common thing to find on a mini these days.

[cap'n crunch]

Does she have that induction roar that side draught webers have.

On the first choke which is about 2/3 of the thottle movement it is quiet and sensible ( and decent fuel economy aswell) but get past that and open them both up and yep the full roar is there and it goes like a bullet.

Oh and the throttle response on the 28/36 compared to Twin HS2 I found was a no contest. 28/36 is much better, probably down to the fact the primary choke is small so air flow is fast. All this talk is making me really want to get my car rebuilt even faster I miss the weber fun!