4.2 linked decat, modded throttles. MBE or Emerald?

[edhorne]

Right then, I've been thinking......

I have my 4.2 to a level now where I am thinking of a few mods. Nothing serious but just something to ensure it is running sweetly and that I know it is performing to its maximum.

I am looking at a linked decat exhaust and hopefully obtaining some throttle bodies to give to one of the usual suspects for some modification. I will need a tappet service soon so I was thinking I could save some of the labour by taking off the old throttles and bolting on the new ones as part of the process.

I would like to see a remap to take full advantage of the exhaust and the throttles with the aim being flatter, fatter torque curve and improved part throttle drivability.

I don't envisage doing many other engine mods while I own the car.

My questions are:

1. Do I need a remap to take full advantage of the above or is there enough fuel in the standard map to cope?

2. Is there an off the shelf chip to improve performance and drivability with the above mods.

If I do need a remap:

3. MBE or Emerald for best performance (will need to put cats back on for MOT)

4. MBE or Emerald for best cost effectiveness? (bearing in mind I don't plan to do other mods)

I have the early 4.2 with clatter cams (not sure on the compression).

I eagerly await your replies.

Ed

[Cyclone1]

Ed,

I could answer all of your questions if I had the time but at the monet I don't so best bet is to give Joolz a call at Track Car Solutions, he'll be able to answer all of your questions and then make honest recommendations in line with your requirements.

Jules

ps then you can post back what your mods are going to be....

[edhorne]

Just had a look at TCS website.

I wonder if the airbox pulse plates would work on a 4.2?

Ed

[southendpier]

edhorne said:

Just had a look at TCS website.

I wonder if the airbox pulse plates would work on a 4.2?

Ed

previous owner took mine (a 96 4.2) to TCS and got an emerald ecu and de-cat and got 360hp on the rollers.

[jensena]

My old 4.2 (Now lovingly looked after by Byker28i) totally standard was 353bhp - so up to 360 isnt neccassarily a huge improvement.

[southendpier]

err, quite.

The length of the journey is as dependent on the start point as the finish.

[Cyclone1]

jensena said:

My old 4.2 (Now lovingly looked after by Byker28i) totally standard was 353bhp - so up to 360 isnt neccassarily a huge improvement.

A healthy well mapped 4.2 is 360bhp at best. However there are plenty of 4.2s out there that put out much less, so a session on the rollers may get it back up to where it should be.

Jules.

[trackcar]

southendpier said:

edhorne said:

Just had a look at TCS website.

I wonder if the airbox pulse plates would work on a 4.2?

Ed

previous owner took mine (a 96 4.2) to TCS and got an emerald ecu and de-cat and got 360hp on the rollers.

erm, are you sure? edited to add: is this PK's old car?

Edited by trackcar on Wednesday 7th March 11:23

[southendpier]

Nope - I have the print out.




editted to add: the previous owner noted this about the car "its fitted with a sports exhaust and recently de-catted...i have recently had it dynoed and it made 360 bhp aswell and have had the cooling mod and mapping to suit the de-cat"

So I am unsure of what fully went into the car at the mo but I can look it up later.

Edited by southendpier on Wednesday 7th March 12:28

[paulk]

No PK still has his car and its still pumping out 365 or so (I hope)

Mods that have been done on my car are in no particular order are,

Linked d-cat pipes
Cone air filters
Smoothed inlet manifolds, = lots of pap taken away
Sports Pipes, which may sap a bit power rather than give any

And thats about it, apart from being well looked after by TCS and HHC

Various chips have been tried with no real improvment also is it the mbe played with a bit again with no real improvement.

My car is a 96 still with clatter cams.

Hope this helps

Paul

[edhorne]

Thanks for the input guys.

I'm not really looking for massive peak power gains. 360bhp would be nice as I think that is what the Autocar test had from the press demonstrator. I have the magazine at home, will check.

I am hoping for a smoother drive with perhaps a little more low down torque.

We'll see!!

Ed

[edhorne]

Just wondered if anyone else has had their 4.2 modded as I was thinking.

Still trying to get intouch with TCS

Ed

[byker28i]

Mines a standard 1997 4.2 with clatter cams and a sports rear exhaust. As Alan said - 353bhp and about the same torque. Can't see me improving much on that

[edhorne]

Certainly the first step would be to see what it is producing now.

However, I would like a little bit better part throttle manners. pots etc are all check and OK on mine. Could be tappet clearances and that is the next step!

Cheers

Ed

[mars]

I still find it difficult to understand how 300cc different between a good 4.2 and a good 4.5 can yield such massive results. If a good 4.2 puts out about 360bhp and a good 4.5 can put out significantly over 400bhp, what is causing this difference? Are the 4.2 throttles too narrow? Are the heads different, with smaller valves? What makes the difference in capacity... bore or stroke (or both)?

A 4.2 (what's the exact cc?) at 360bhp is 86bhp/litre
A 4.5 (4475cc) at 420bhp is 94bhp/litre


Put it into perspective, my little Caterham at 244bhp for 1886cc was 129bhp/litre. Bit unfair as it's a 4-valve/cyl head.

And a 5 litre Chim at 360bhp is 72bhp/litre.

Lot of variety in specific outputs. It's not a scientific comparison but quite interesting.

[Steve_T]

There's got to be more to it than the capacity, don't know what. I do remember Melling being adamant at the Middle Wallop talk that 360bhp was the limit for the 4.2 though.

[HarryW]

It is a tricky subject, the intakes are restrictive on the 4.2 as are the manifolds (poss more so). Mine is now a 4.5 and running a 'safe' map with standard 4.2 intakes and crimped 4.2 manifolds and is currently exceeding 400 on the bench dyno, so whilst they are restrictive they are not at their ultimate limit at 360hp or even 380 as I think another 4.2 is runnning imho.
As another example DAZ's old car (wanna be cerb??) is a rebuilt 4.2 with 4.5 internals and in the car running with the standard 4.2 intakes/manifolds and is just shy of 390hp and still loosening up.

[trackcar]

southendpier said:

Nope - I have the print out.




editted to add: the previous owner noted this about the car "its fitted with a sports exhaust and recently de-catted...i have recently had it dynoed and it made 360 bhp aswell and have had the cooling mod and mapping to suit the de-cat"

So I am unsure of what fully went into the car at the mo but I can look it up later.

Edited by southendpier on Wednesday 7th March 12:28

so not an emerald car then? I thought it was strange as I have never fitted a 4.2 with an emerald except as a test once, indeed the only 4.2 i know of with an emerald is carbon al's which emerald themselves fitted many years ago.

[southendpier]

trackcar said:

southendpier said:

Nope - I have the print out.




editted to add: the previous owner noted this about the car "its fitted with a sports exhaust and recently de-catted...i have recently had it dynoed and it made 360 bhp aswell and have had the cooling mod and mapping to suit the de-cat"

So I am unsure of what fully went into the car at the mo but I can look it up later.

Edited by southendpier on Wednesday 7th March 12:28

so not an emerald car then? I thought it was strange as I have never fitted a 4.2 with an emerald except as a test once, indeed the only 4.2 i know of with an emerald is carbon al's which emerald themselves fitted many years ago.

furry muff, my error.