AJP 4.2 upgrade?

[DCerebrate]

Never mind the power, that is one beautiful torque curve........

[Tanguero]

But at that price, I do mind the power...!
Admittedly it runs superbly and has a lot of torque, but a 4.7 is not a good way to large power increases.
4.2 = 352
4.7 = 392
40 bhp = £355/bhp

Edited by Tanguero on Monday 27th March 22:51

[ukkid35]

Tanguero said:

Yes

4.7 (including billet crank & 2 cam shafts) = £14.2k inc VAT!!!)
After remapping by Joolz

Sure, the headline bhp is missing, but look at that torque curve - that is awesome!

Here's my 4.5 chart, it's peaky but the torque is missing

[ukkid35]

I still think that bhp is there if you dump the 4.2 induction.

Sure the 4.5 airboxes are the work of the devil, and seeing the injectors dump fuel directly on top of the butterflies looks absurd (especially at idle) - but it I reckon that is the answer it you want bhp.

[Jhonno]

Tanguero said:

But at that price, I do mind the power...!
Admittedly it runs superbly and has a lot of torque, but a 4.7 is not a good way to large power increases.
4.2 = 352
4.7 = 392
40 bhp = £355/bhp

Edited by Tanguero on Monday 27th March 22:51

I have heard a rumour they have changed the pin in the piston, which seems to be affecting the power of the recent 4.7's..

Also, if you are running standard 4.2 induction.. The throttle bodies need working a little and the standard injectors run out at 400bhp (running flat out at 100% duty). Joolz will flow your throttle bodies.

[Jhonno]

ukkid35 said:

I still think that bhp is there if you dump the 4.2 induction.

Sure the 4.5 airboxes are the work of the devil, and seeing the injectors dump fuel directly on top of the butterflies looks absurd (especially at idle) - but it I reckon that is the answer it you want bhp.

Love that pic..

[aide]

ATG said:

Given no one has suggested it yet, I'm guessing forced induction isn't a good option?

Has been done in the past though:

[Byker28i]

Tanguero said:

Byker28i said:

Anyone got a graph of a 4.7 at Surrey Rolling road?

Yes

4.7 (including billet crank & 2 cam shafts) = £14.2k inc VAT!!!)
After remapping by Joolz

Blimey - that's not a huge power increase, nice torque. I trust Charlies figures. I've always been surprised by people turning up on shootout days with suspiciously high claims.

This was mine after is left Joolz remap and inlet work


But it had a cracked manifold which was swapped out for ACT ones and I changed both coil packs before this at Surrey Rolling Road



The nice thing with mine is the torque comes in earlier - makes it very driveable, before it was a bit of a pig below 3K revs.

Edited by Byker28i on Tuesday 28th March 10:04

[Byker28i]

Thomas - I'm happy with mine. Drives well, goes well, just trying to make it look as good as well now. I've rather concentrated on the mechanicals the last few years.

[Incognegro]

thomas.moeller said:

This could have been a great solution but, I need to a pre-1997 engine due to taxes (don't ask. This is just one of the things you have to accept when living in a car hostile country). Actually this is the reason why I did not buy a 4.5 to begin with.

You may find your 4.2 has a 4.5 bottom end as many of the cars were made that way... so you effectively have a 4.5 with 4.2 induction?

Dom at Powers performance would be my go to guy as a 4.5RR update should/could see 450bhp

[CerbWill]

As I've got a 4.2 I've often wondered about the tuning options available for it. Mine's now on 81k miles and I keep telling myself I'll have it rebuilt at 100k so spending on a remap now doesn't make sense to me. I've already fitted 4.5 manifolds and I'll think about the 4.5 exhaust mid section. Would porting the throttles provide gains without mapping?

For those posting RR graphs in this thread can I ask the stupid question if these figures are at the wheels or flywheel?

[Jhonno]

I would port the throttle bodies and get the injectors cleaned at the same time. It will give some nice gains!

[Byker28i]

CerbWill said:

For those posting RR graphs in this thread can I ask the stupid question if these figures are at the wheels or flywheel?

There's so many factors in this, how the road is setup, the losses assumed, the enviromental factors entered, that unless you have a shootout, i.e. several cars on the same rolling road, then there's no real comparison. It's an advantage for some to claim large numbers.

I've been on three shootout days. Once before the car was sorted, when it always used to record between 341 and 343bhp and since mapping, throttle body work and exhaust etc, when it's always hit 380bhp plus or minus 0.6bhp.

Everytime I've been someones been upset their car doesn't meet figures they've been expecting. They've had an upgraded engine, they've been shown a graph, then it gets nowhere near. Last time was a S6 engine with £18k of work was supposed to pull 440 but only delivered 384bhp.

However Charley did have a Racing Green FFF engine on the rollers at 436bhp, which was impressive.

From the old 2011 shootout:
Graham - Cerbera 4.5 426.3bhp, 360 ft/lbs
FrmYardPants - Cerbera 4.5 410bhp
Fubar - 4.5 Cerbera 406bhp 365ft/lbs
Ridds - 4.5 Cerbera 390bhp
D14AYS - 4.5 Sagaris 386.9 bhp 345ft/lbs
Byker28i - Cerbera 4.2 - 380.7 bhp 330 ft/lbs
Noisy - Cerbera 4.2 - 377.7 bhp
Pmessling - Cerbera 369bhp
GT6K - Cerbera 4.5 365bhp
Demondad - Cerbera 4.2 364.8bhp
TC - Cerbera 4.2 364bhp
Englishman - Sagaris 353.5bhp 300ft/lbs
WhyTwo - Cerbera 4.2 341bhp
Biper - Chimaera 500 302.3 332 ft/lbs

An interesting read this - especially about the results
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[Byker28i]

And the original thread about the mapping and port work
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

From this:
The 4.2 inlets have a few area which need addressing to improve flow, mainly centred around the butterfly spindles, the area just immediately after the butterflies and the waisted section at the manifold to head face. The inlets need stripping down off the car in order to do it and refitting/balancing when back on the car, plus one slip in the butterfly area and it's an expensive mistake so time/patience/care are the order of the day .. hence the cost is quite high.

Add to that a remap and cooling mod (bringing the fans on at 90 rather than 95) for the complete package.

[CerbWill]

Annoyingly I've got Edhorne's old car but it never made it up to Jools for one reason or another. Whilst the reasons why dynos vary is a bit beyond me I do understand that flywheel figures can be made to vary quite significantly, whereas I thought at-the-wheel figures would be easier to replicate on various dynos. I took my car down to a local place for a power run a couple of years ago and came away with 283 at the wheels. The car was totally standard at that point. I do have a receipt for injector cleaning in the car's history but off the top of my head I cant remember how many years and miles ago it was. A recent Sprint article on dynos & testing suggested the transmission loss is about 45BHP on many TVRs which would put mine at 328 at the fly. If the figures above are all at the wheels then I'm well down on power, if they're a the flywheel I'm a bit down.

[Jhonno]

CerbWill said:

Annoyingly I've got Edhorne's old car but it never made it up to Jools for one reason or another. Whilst the reasons why dynos vary is a bit beyond me I do understand that flywheel figures can be made to vary quite significantly, whereas I thought at-the-wheel figures would be easier to replicate on various dynos. I took my car down to a local place for a power run a couple of years ago and came away with 283 at the wheels. The car was totally standard at that point. I do have a receipt for injector cleaning in the car's history but off the top of my head I cant remember how many years and miles ago it was. A recent Sprint article on dynos & testing suggested the transmission loss is about 45BHP on many TVRs which would put mine at 328 at the fly. If the figures above are all at the wheels then I'm well down on power, if they're a the flywheel I'm a bit down.

Tbh, the 2 dyno's I know and would trust are SRR and Evolve in Luton. They are both known for no bullst and being within a BHP or 2. Anything else could be a lottery up or down.

[FarmyardPants]

Tanguero said:

Yes

4.7 (including billet crank & 2 cam shafts) = £14.2k inc VAT!!!)
After remapping by Joolz

A 4.5 graph for comparison (SP exhaust, short induction, remap)



Pmax at 7,350rpm and a lot less torque, but smooth. You have to really wring it out but it flies when you do!

Edited by FarmyardPants on Tuesday 28th March 13:18

[FarmyardPants]

I would expect the 4.7 to feel a lot faster from the passenger seat and pull away from me in all situations bar an Autobahn drag.

[ukkid35]

aide said:

Has been done in the past though:

You can't fault Paul's superb fabrication, but since the AJP8 is SOHC that means you can't easily change the overlap so that is it more appropriate for forced induction.

[aide]

ukkid35 said:

You can't fault Paul's superb fabrication, but since the AJP8 is SOHC that means you can't easily change the overlap so that is it more appropriate for forced induction.

When I took that pic at Ace cafe a few years ago, Paul mentioned that it dyno'd to 560bhp @ 6200 rpm and couldn't rev any higher as the wheels were spinning on the dyno! However, he didn't say if it had std cams?