DTH TB vs Roller barrel

[jackb_ms]

Hi

 

I'm looking for some data about the air flow for the Jenvey DTH TB and the CC roller barrels

 

My search on the interweb, have not be very fruitful. Can someone help?

 

Cheers

 

Jack

 

Emily, The Very Yellow 21

[simonbell]

FWIW certain well know tuners don`t like roller barrell TB`s

 

Simon Bell - Caterham 7 Duratec R

I`ve seen the future.....and it`s powered by duratec Check out the website here

[caterhamnut]

My understanding is that the advantage of RB's is negligible in everyday use - are they not only better at 100% fully open, when they become totally open and unrestricted, where as when they are at say, half or 3/4's throttle, there is a massive step in the way of the air flow, where as the Jenvey DTH TB's will only have a 'vane' 'blocking' the air flow.

 

Simplified explanation maybe...I do remember someone who knows saying that having them as standard on the R300 was more about 'spec list porn' than actually needed, and the money saved by not having them might have been better spent elsewhere?

ISTR RB's are pretty expensive...

I stand to be corrected on all of that - just what I remember hearing/reading sometime!!

 

www.mycaterham.com

here

Videos

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96,000 miles -1st 1.6k Supersport, '95 Motor Show car

[paul jacobs]

Hi Jack, how are you doing? Whether it's anything to do with roller barrels or not, I'm not sure, but the intake noise on my Duratec, fitted with said RBs is almost non existant, compared with my old 245bhp Vx fitted with standard DHTBs, which was manic at higher revs, much louder than the exhaust. Some like this, some find it very wearing on longer journeys ☹️

[Casbar]

Taken from Dave Andrews web site, who has plenty of knowledge on things K. "The R500 engine uses roller barrel throttle bodies which minimise obstruction and drag in the inlet tract, these represent pretty much the ultimate in induction systems but are pretty expensive, Below is a photo which shows them in situ"

 

I suggest you give Dave a ring or mail him and ask him the question, rather than armchair therorists

[Red SLR]

I have had cars with both RBTBs and Jenvey DTHTBs. I did not notice any massive difference. I guess the main advantage comes on very high output engines as it allows less restrictive airflow on WOT and gives less turbulance.

 

LeMans 2006 photos here

[SLR No.77]

... and there's plenty of high powered Caterhams running on DTHTBs. At full throttle the roller barrel TB has nothing obstructing the inlet, whereas a traditional butterfly valve will always cause an obstruction, however minor. BUT, very little time (unless racing) is spent with the throttle wide open, therefore other factors come into play. There's been plenty discussed on this in the past, but briefly, as stated at part throttle openings the roller barrels disturb the airflow rather unsatisfactorily when compared to traditional butterfly valves, and therefore need very careful mapping. Not really achievable "off the shelf" but very realistic with a full rolling road session. Definately more bling than reason to them!

 

Stu.

[Mark Durrant]

Paul

 

I think the lack of induction noise from the RB's on your Duratec is a characteristic of that engine as the 'bark' from the RB's on my R500 is manic and very addictive 😬.

 

Mark D

Comp Sec

 

[DEyres]

Hi Jack

 

I spoke to Dave Andrews aka Oilyhands (top man! ) about rollerbarrels and he said, more or less, that Jenveys would give much the same result at a more reasonable price.

 

As others have pointed out the only difference is that when fully open a roller barrel tb has nothing in the airflow. The benefit of this against butterfly throttles is probably quite small, but if you are chasing total power then its something that will help. Unless you are blessed with vast amounts of cash to throw at the engine then I would look at spending the money elsewhere. According to Dave's web site the Jenvey's are good enough for 250 BHP and thats probably enough power to empty your pocket 😬

[Jason Plato]

Rollers : potentially a few more bhp at the very top end , potentially more troblesome to maintain and setup , possible a little less user friendly at small throttle openings - like general road use.

 

Plus they are generally heavier and more expensive and you cant fit an airbox under the bonnet on a DURATEC ( did originally type K as its inground in my mind) 😬

 

Dave

 

 

 

here is C7 TOP

South Wales AO

 

Edited by - Dave Jackson on 4 Oct 2006 10:10:52

[caterhamnut]

phew - so I was roughly correct, as I sat here in my armchair.

 

www.mycaterham.com

here

Videos

here

96,000 miles -1st 1.6k Supersport, '95 Motor Show car

[jackb_ms]

Thank you gentlemen for all that

 

My thoughts are as follow:

Roller barrel flows about the same as DTH TB.

So logically a ECU which was programmed for a roller barrel should work with DTH TB.

Yes or No?

 

I believe it will be no, I just don't really understand why, just a kind a gut feeling type of thing.

This is why I am looking for some data showing how the air flow goes trough a roller barrel and a DTH TB

 

Cheer Jack

 

PS: I want to use my car a lot more on the road than on track.

 

Emily, The Very Yellow 21

[mav]

you cant fit an airbox under the bonnet on a K

 

you can!

[SLR No.77]

and you cant fit an airbox under the bonnet on a K

Surely purely a cost issue - RBTBs & CF air box as per the option on the R500

[SLR No.77]

Note to self:

Must learn to type faster!

 

Ecu should be reprogrammed if going from RBs to DTH TBs.

 

Stu.

[Alex Wong1697456877]

I believed I was cured from upgraditis.

 

I've been talking about devoluting (is that a word?) my car for ages, but for some reason, I've just bought some rather nice Swindon roller barrels. With eight injectors. Oh and nice carbon fibre rampipes.

 

This will mean a new ECU for me, new loom, fitting the steel rods from my old engine to the new one, remapping etc etc

 

 

Upgraditis... There is no cure.

[Jason Plato]

yes - your right of course an airbox can be fitted on a k 😬

 

I meant to Type DURATEC 😳

 

my mind thinks duratec but after 8 years of k ownership subconciously I type K series 😬

 

here is C7 TOP

South Wales AO

[oilyhands]

A map for RTBs will *not* be the same as for DTHTBs, because the airflow profile by throttle position will be different, as will the engines response to the marked difference in airflow characteristics at near closed and part throttle. A conventional butterlfy at part throttle gives a fairly even distribution of air around the circumference of the port in a annular ring, a roller barrel distributes the air only at the top/bottom of the port depending on geometry.

 

Oily

[Red SLR]

Mine used to whistle at 1/8th throttle sometimes, all balanced ok etc, very odd!

 

 

 

LeMans 2006 photos here

[dannylt]

On a butterfly you can just have a slightly larger bore to make up for the loss of flow anyway - if max power is what you care about. As for the larger obstruction at part throttle - well, at part throttle you don't care about power anyway, otherwise you'd open the throttle more. But possibly easier to map around the opening point? Also, I can't see why either would be quieter at full throttle - they are both very noisy.

 

 

[Jason Plato]

yes Danny , power isnt important at part throttle but the rollers can affect driveability and progression. 🤔

 

Guess the choice realy depends on what you will be using the engine for and what your wlling to compromise.

 

it should be remembered that the rollers are anodoised gold so they must be faster 😬

 

here is C7 TOP

South Wales AO

[AMMO]

Roller barrels.

 

Don't like 'em, don't wan't 'em, don't need 'em.

 

The last Ferrari F1 engine I saw had butterflies. Nice oval ones in the oval bellmouths. Must have been a pig to make. Superbikes, where throttle control is paramount, all have butterflies.

 

Dave (Jackson) Please give me a call if you read this . Ta

 

 

 

AMMO

[jackb_ms]

I was planning of keeping the OEM ECU for my version of the VVC-R

 

I wanted to check that the map for the roller barrels TB will be compatible, and the answer is no.

 

 

Thanks a lot

 

Jack

 

PS: does someone got some roller barrels which they are not using?

 

Emily, The Very Yellow 21

[Spartacus]

a roller barrel distributes the air only at the top/bottom of the port depending on geometry.

---

 

AFAIK, the Swindon ones use two rollers and effectively open like the iris on a camara lens.

[Peter T]

Yes they do, the Swindon versions do not suffer from bad fuel attomisation at low air flow due to the central air swirl being in the middle of the trumpet port, slide throttles and top/bottom rotating barrels are not as smooth for promoting good air flow compared to the Swindon design.

 

R500 Mango Madness