ACT Manifolds for AJP8
ACT Manifolds for AJP8
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Discussion

longbow

Original Poster:

1,610 posts

265 months

Tuesday 25th March 2008
quotequote all
Just wanting a bit of info on the ACT manifolds, from those who have bought them already;

1. Are they port-matched to the AJP's D shaped exhaust ports? The standard manifolds aren't!! I guess if I am going to spend around 1k on manifolds I'd want them to be well matched.

2. Is a remap strictly necessary, as ACT claim?

I really like the way they dismantle in sections which will greatly help as and when the clutch needs changing or the slave cylinder goes etc. I also like the cleaner 4:2:1 setup. Any feedback greatly appreciated!!

TT Tim

4,168 posts

277 months

Tuesday 25th March 2008
quotequote all
Hi Windsor,

Re the remap. Get your car on a trusted rolling road and check the figures.

My fueling was way off, so after changing the fuel pump for a nice shiny new Bosch motorsport varient the car went of to TCS.

He doesn't usually carry out remaps on the 4.2 as he says the returns aren't worth the money, however the figures on mine and the way it drives are now fantastic.

Call Joolz, he's very open to having a chat.

I'm guessing that if the exhaust has that dramatic an effect then some remapping may be needed.

email me off line if you want a ballpark figure of the cost.

Tim biggrin

Edited by TT Tim on Tuesday 25th March 15:19

Cyclone1

2,614 posts

276 months

Tuesday 25th March 2008
quotequote all
I wouldn't really think you would need a remap if you are just going to change your manifolds, unless that is that your current set-up isn't at it's optimum. If this was the case then there may be some fair gains to be made to both performance and driveability. So what I am saying is that if your car is currently in a healthy state of tune then the addition of the manifolds wouldn't really warrant the rolling road time.

When I had my Cerb I looked into having a set of manifolds made, but the rapidly decreasing state of the existing manifolds dictated that I change them sooner rather than later. I had two options, one was to buy the ACT kit (very nice it is), the other was to source an existing standard set or v good second hand set. I did a bit of digging about the potential gains of the new ACT system (bhp mad!!) and at the time wasn't convinced that this would offer that much more than a standard set-up (I had seen a few on the rolling road with remaps etc). I was lucky enough to source an excellent condition second hand set for just under £300 so I snapped them up. All I did to them was to very slightly port them (clean them up really as there was hardly any room to do too much TBH) and then refaced them, fitted them and that was it. Testing showed a gain all the way through the range with little or no tweaking to the map needed, but the gains were to be expected as the previous set of manifolds had been welded a few times in their life.

The only time we had to adjust the map was when the linked de-cats were fitted (diff configuration to std and therefore flows gasses differently) and the Big Bore Exhaust I had made and fitted, but yet again the gains were big without touching the map and then slight fueling adjustment to optimize the existing map.

Things to weigh up are cost, accessibility (big consideration if you work on the car a fair bit which you do) and gains. At the end of the day you spend £1k and should never have to change them again......

Tim is right about giving Joolz a buzz ref getting your car checked out and possibly reset up...

Hope this helps,

Roll on FT2'08

Jules.



Edited by Cyclone1 on Tuesday 25th March 15:40

longbow

Original Poster:

1,610 posts

265 months

Tuesday 25th March 2008
quotequote all
Tim, have you had the MBE remapped or gone for the Emerald? What sort of figures is your 4.2 putting out then?

To be honest, short of junking the AJP for an LS7 I'm really running out of things to do on the Cerb now. I actually left the car alone yesterday and sat and watched tv all day instead, I just didn't have a single job or thing to fix!! And who says TVRs are unreliable getmecoat

TT Tim

4,168 posts

277 months

Tuesday 25th March 2008
quotequote all
Cyclone1 said:
I wouldn't really think you would need a remap if you are just going to change your manifolds, unless that is that your current set-up isn't at it's optimum.
I think that sums up my whole post in a single sentence, wish I'd written that. yes

Surely, a £50 Rolling road session is going to show you the state of things after fitting the manifolds? Then you could decide if it's worth it. scratchchin

Tim biggrin

TT Tim

4,168 posts

277 months

Tuesday 25th March 2008
quotequote all
longbow said:
Tim, have you had the MBE remapped or gone for the Emerald? What sort of figures is your 4.2 putting out then?

To be honest, short of junking the AJP for an LS7 I'm really running out of things to do on the Cerb now. I actually left the car alone yesterday and sat and watched tv all day instead, I just didn't have a single job or thing to fix!! And who says TVRs are unreliable getmecoat
Joolz wrote a bespoke map for my MBE.

I'll shoot you a mail. biggrin

Tim

markh1

2,846 posts

239 months

Tuesday 25th March 2008
quotequote all
My car was re mapped sometime before I fitted the manifolds. After fitting the ACT's there was a noticeable difference. More torque and better acceleration, very free revving and slightly louder. I am thinking of getting the SP exhaust as well but that would be 2 grand just on the exhaust system!

ACT

2,529 posts

314 months

Tuesday 25th March 2008
quotequote all
Re-mapping isn't essential, but recommended, with mapping after fitting our manifolds you can achieve far more ignition advance in the low-mid range rpm and make gains so there is value to mapping.
Tim ACT

longbow

Original Poster:

1,610 posts

265 months

Tuesday 25th March 2008
quotequote all
Oooh, Tim....... whats the score with the port-matching then? Even if it isn't standard, would it be possible as maybe a one-off via JP?? When I did my rebuild I thought the D-shaped exhuast port to round manifold was a bit poo, and I'd really like to address it if possible. Thanks thumbup

ACT

2,529 posts

314 months

Tuesday 25th March 2008
quotequote all
They are matched to port shape

caduceus

6,130 posts

296 months

Monday 31st March 2008
quotequote all
Wins, did you go for these manifolds in the end?

longbow

Original Poster:

1,610 posts

265 months

Tuesday 1st April 2008
quotequote all
Not yet Cad, I will do the next time I need to remove the gearbox or similar. The car's running very sweet at the moment, so I'm going to leave it like that for the summer so I can have some fun!!