420r Upgrades ?

[mschraider]

I have a 2017 420r and am starting to think about potential mods and upgrades. 

I'm thinking initially that I'd like a little more noise (and maybe power) so am after some recommendations from those that have been down this route.
 

I don't want to go full RBTBs (cost, but also don't want to cut the bonnet), but wondering if there are any other options to improve the air intake ( can the standard air box be replaced with a K&N cone ? If so, which one ?) and whether a decaf would help ?

Any other recommendations on a good first couple of steps ? 
 

Thanks

[AdamQ]

I'll jump in on the proviso that it's understood that I'm mildly experienced but no expert in any way, shape or form ...

Regarding the air intake, I have Jenvey TBs getting their air through an in-line K&N from under the radiator - no bonnet cut-out (and it's an Imperial S3).  I believe Jenveys are about half the cost of the full RBTBs.  I'm not sure they influence power greatly, but I think the throttle response is supposedly somewhat sharper.  I can't see why you'd need a rolling road session or a new ECU with this change, but it might be that you would and there would probably be benefits, minor or medium.

As for exhausts, Powerspeed are always well spoken of - I have a 4-2-1 from them - I think the 4-2-1 is supposed to give better torque than a 4-1 but I also seem to remember Chris at Raceline telling me a while ago that the gains were marginal, bordering on negligible.

I've had two Duratec-engined Sevens.  The engines were identical except that one had a mildly ported head.  BHP figures were the same, but the torque for the engine with the modified head was significantly higher, so maybe that would be an idea.  My understanding is that the Duratec flows very well even in standard form, but there appear to be improvements to be had - though I'm not going to suggest any certainty on the basis of a single data point.

I guess a 2017 car has the Mazda gearbox?  I don't know what the ratios in that are, but if they're not similar to the ratios available from Tracsport for the Type 9, I'd be very tempted to be looking in that direction for an improved 'driving experience'.

Those are my thoughts, for what they are worth ...

Adam

[BigCol]

Given that his car and its aerodynamics were featured in a recent Low Flying, I assume David Long is a member.

For anyone that has followed his Engines and Gearboxes in Detail on facebook, he knows his stuff when it comes to Duratecs...

If you're lucky, he'll be along soon...

[7 wonders of the world]

You need to decide what you want from the car...?

If your looking for good power gains then you may have to cut the bonnet otherwise you can spend a considerable sum only to compromise what the engine requires by making it breath warm air thro a smaller than optimal filter crammed under the bonnet.

Jenveys will offer better driveability and transition due to the manner in which they allow the air to flow around the circumference of the butterfly which induces turbulence aiding combustion. NB most if not all rally and BTCC cars opt for butterfly TB's over roller barrels.

Whatever upgrades you do you WILL need a remap..... as a reference a 10mm increase in intake length lead to a 12% weakening of the fueling at peak torque on the Emerald rollers.....

Even minor changes can and do affect fueling and timing requirements.

Ratio's yes the stock ratios are carp, Steve's Tracsport are the best gearsets out there and offer a proper 1st ratio for a Caterham of 2.29:1 assuming your car has the Type 9...?

For decent power the stock CC exhaust is fine, better than the ones mentioned in the post above, if your looking ofr a custom set of pipes built to your spec and superb quality speak to Mike Edwards Motorsport in Wisbech he made a perfect set for myself and another member.

 

[ChrisC]

2017 420R with either have a 6 speed or the 5 speed Mazda.  It would be possible to convert to a Type 9 from a Mazda, but I suspect by the time you factor all the bits needed from a bellhousing, propshaft, gearstick and mounting brackets you might be into RBTB's money. 

If you are talking about air filters and decat pipes, then power increase is going to modest if at all, but I suspect noise would increase a fair bit.   Why not look at the K&N panel filter that fits into the air box (from the 310R).  I believe a decat 420R likes flame a bit, which if true will be reason enough for me to fit mine.  

I would be looking at a trip to Track N Road, and getting the stock map converted to a custom map for your car, they have the Caterham codes / software, so they are able to alter the stock locked ECU.   

[Richard_420R]

I've been thinking the same re my 420R ... suspect I'll go the RBTB route from Caterham even though a tad pricey.  Are people satisfied the 'factory' upgrade with remap provides a decent improvement?  I'm really after more noise and 'drama' and maybe a bit on the top end - does the ECU upgrade include a rev limit change by any chance? 
 

Rich.

[elie boone]

A flat slide throttle body would be smaller leaving more space for the air box and a possible cold air intake but i am not aware of these flat slides exist for the Duratec engine.

[Nigel B]

I fitted a decat pipe to my 2017 420R last year. 

It’s noticeably louder now. At tickover it’s as if you’ve turned the bass control up a couple of notches, definitely a bit ‘beefier’ sounding. There’s also an increased ‘raspiness’ from about 2500rpm. 

I’m interested to see where this thread goes, as I’ve been toying with the idea of an upgrade to ITBs too. My previous 7 was on twin webers & I do miss the drama of the induction snarl! 

[7 wonders of the world]

Slides are not the most well manner either - they have the same characteristics as rollers fine for WOT but lack the control of a buterfly.

[Richard_420R]

@7 wonders - what's your take on the Caterham-fitted RBTB solution vs other options? 

[Benton]

For what it's worth....  I've run the Caterham RBTB and a decat on my 420R for over 6,000 miles now.
Improvements for me included much better pickup/response/no kangarooing, cold running, more mid range torque (seat of the pants measurement), great induction noise and lots of pops and bangs. The only downside is the pops and bangs at inappropriate times and places, though you can control these to an extent with your right foot and as an aside the throttle pedal weight is increased but you soon get used to it.

As mentioned the decat pipe gives a more bass tone to the exhaust note, though one of the prime reasons I fitted it was I felt sorry for the catalytic converter being subjected to abuse.

Although the car was remapped by Caterham I'm sure it has more potential that could be released by a visit to Track N Road though I haven't felt a need to do so far.

[7 wonders of the world]

from a resale point using only factory parts and fitting under an uncut bonnet there fine.

however if your wanting a better performing option to unleash the engines potential then there are better options, that are cheaper too enabling you to spend the dosh on cams rods pistons DS etc 

Mines on Jenveys and unleashes 272 BHP       bonnet cut was essential and I opted for a thro the bonnet exhaust too so my under bonnet temps are no issue at all.

[7 wonders of the world]

This might interest you

https://www.lotus7.club/forum/market-place/duratec-360420-decat-pipe-sale

 

[elie boone]

7WOTH flat slides have indeed the same characteristics as roller barrels but takes much less space leaving more room for a cold air feed.

[7 wonders of the world]

They may offer a better installation form a packaging perspective however they are not a good from a driving point and you may still need a hole in the bonnet depending upon what intake lengths your engine requires.

My philosophy has always been the same when assessing a product, firstly does it work...? after that I will consider price, brand, construction etc etc

[Richard_420R]

@7WOTW I assumed that the Caterham RBTB needs a bonnet cut - is that not correct?  I thought I've seen the Pipercross foam filter sticking out on cars that have had the upgrade. 

[7 wonders of the world]

Correct but you could use the pipercross airbox or a normal pipercross filter with the deep plate box CC use along with shorter trumpets to enable a no cut install - performance would suffer though.

https://www.thepipercrossshop.co.uk/px600-airbox_c278851_281227.htm

https://caterhamparts.co.uk/other/4748-air-filter-backbox-carbon-csr-05-cosworth-260-only.html?search_query=air+filter&results=123

[Tazio]

Why the compromise?, whats wrong with having a hole cut in the bonnet?, seems daft to me, you want to upgrade, then seem to want to 'strangle' the engine. Bonnets are cheap.

[7 wonders of the world]

Agree..... 95% of my filter is now external 

[wiltsathome]

I have just bought a 420r that had Caterham RBTB's fitted recently along with the generic Caterham map. After my first few drives and tank of fuel I concluded it was running horribly rich. I took it to the 'two Steves' for a proper mapping session and they transformed the car and improved the fuel consumption by around 30%. It now drives superbly, is totally tractable, gives an honest 209 bhp on ordinary unleaded and with my relatively high mileage (8000 a year in my previous Roadsport) it's affordable. 
In my view, whatever mods you do and whichever TB's you choose, or leave standard, a proper mapping session will be where your biggest gains will come from. 
If I was doing the mods myself I'd go for Jenvvey type TB's as the guys that know say there is no advantage to the roller type and use the change on a decent 4-2-1 manifold, that would get you all the grunt and torque delivery. 
(BTW I run a single seater with a 2l spec BTCC engine from the good old 300plus bhp days, it's on Jenvvey's and single injectors and behaves superbly, rollers and slide throttles were tried in its development)

[dave_h34]

Good advice here. Unless you're fixed on keeping it original I think I'd be tempted by the better driveability of butterflys than the marginal/theoretical gain of rollers. You'll probably save enough money to more than cover a full remap, so better solution at lower cost.