50mm throttle bodies on a 2L Zetec

[magnusfeuer]

Fellow blatters,

I am thinking about buyng a setup from TWM Induction (http://www.twminduction.com - cick on throttle bodies/2000 series), and noticed that their Zetec kit has 50 mm bodies. Jenvey, I believe, run 40, 42, and 45 mm.

 

This raised a bit of concern regarding idling and cold start of the engine, which will have either an Emerald or Pectel unit and sharper cams to get the engine to ~200hp.

 

Has anyone tried 50mm throttle bodies on a 2L Zetec in the 200hp range?

Theoretical opinions and recommendations?

 

Tnx!

 

/Magnus F.

[oilyhands]

50mm seems way over the top to me, 45 or even 42mm TBs are more than adequate for a 2 litre giving that sort of output, cant see idling and start being too much of an issue but you may loose some mid range torque.

 

Oily

[Colin R]

My father and I live near San Francisco and have just received a conversion kit for a 2.0 Zetec Supersport (200+hp). The kit comes with a TWM 2000 series Throttle Bodies and Pectel ECU. We purchased everything from Caterham USA and I suggest you send them an email. We have a long relationship with a guy named Jon Nelson there, who would be more than happy to help you out. If you go to the website you can check what they spec their high output Zetecs with. Hope that helps. By the way, I got a test ride in a superlight R from Caterham USA a little while back fitted with the Supersport engine configuration we purchased and let me assure you, it is a monster! The very car I rode in was featured in both Auto Week and, I think, British Car Magazine. My facial features are still contorted from the acceleration g's. Good luck.

Colin Ritchie

[magnusfeuer]

Colin,

 

Jon is the guy I will be purchasing the kit from, if I go the TWM route. In the process I am trying to get people's opinion on the kit's specification.

 

Did the Superlight have the TWM?

 

/Magnus F. (in Orange County)

[Colin R]

Yes it did. We took pics of the engine bay from every angle for reference. TWMs, but I don't know how large.

[AMMO]

50 mm throttle bodies may not be too large. It depends on a lot of things. The distance of the butterfly from the valve for instance. The further away the butterfly is the bigger the throttle body needs to be.

 

On a big valve ported head with hot cams I would say that the 50 mm is worth a try. In fact on my mildy ported Zetec head (originally ported for carbs) 45 mm carbs with 36 mm chokes gave an 18.5 cfm restriction and the 45 mm throttle bodies a 6 cfm restriction. This indicates to me that a larger throttle body would give more power as long as the engine is capable of using the extra air available.

 

The 45 mm throttle bodies I bought second hand were briefly fitted to a 2 litre Vauxhall Touring Car. They were taken off because they were too small.

 

Large capacity V-Twin motorcycles with individual throttle bodies run 50 mm as standard on the road. They are upgraded with 54mm bodies and always pick up power (usually around 9 bhp on both Guzzis and Ducatis). Obviously you just can't plonk them on the whole induction system must work in unison.

 

World Superbikes run 60 / 65 mm individual throttle bodies. Even the 4 cylinder 750 / 1000 cc bikes run 45 / 50 mm bodies. The Suzuki 750 / 1000 cc bikes I have worked on have no restriction when the throttle body is fitted to the head on the flowbench. Seems to work.

 

Unfortunately the only way you will find out 100% if it will work is to try it. I have recently supplied a set of Jenvey 50mm bodies to a friend to put on his hot 2 litre Zetec. They turned up cheap and were worth a try. The plan is to make some chokes to put in the end of the throttle bodies (like a carb) and run them fully open and with 45 mm and 48 mm chokes to see what happens. Should have some hard evidence at some point.

 

AMMO

[JamesA]

Colin,

What was included in the conversion kit to the 200 hp supersport? Or even more basic, are you converting from the standard 145hp 2 liter to the 200 hp SS? I am like you and Magnus, I want MORE HP! What is the emission compliance strategy with the 200 hp, I would think you will have a problem with HC compliance.

[JamesA]

Magnus,

I know you have an SV as I do, based on advice from Geoff (Miraz) on this forum I uprated to 250 lb/in front springs and Caterham 21 springs on the rear and it is fantastic! Good on the street but fantastic in autocrosses and track use. A big improvement. I am fitting Mintex 1155 pads this weekend as the standard pads don't hold up well on a track day.

Jim

[magnusfeuer]

AMMO: Thanks for your (as usual) valuable input. If the bodies work with relatively mildly upgraded cams (no headwork), and provide a good foundation for future upgrades, I may give them a try.

 

JamesA: I will look into the uprated springs as a part of the overall package. I should probably invest in LSD prior to that, though.

 

Thanks for your input!

 

/Magnus F.

 

 

[Colin R]

James,

A year or so ago Senate Bill 100 was passed which allowed us to put whatever we'd like into our car without emissions restrictions. I think we classified it as a reproduction of a car outside the 30-year emissions window. I believe a link exists on the Autocourseinc.com website (they sell Sevens out of So Cal.) that explains it ad nauseum. Without it, you're absolutely right, we'd be up a creek.

 

We are converting from 155-hp XF to Supersport. After a year of trouble with our XF (never even broke 1,000 miles) we bit the bullet and decided to upgrade. My dad wanted 180, but I lobbied hard for 200+. Caterham USA was nice enough to let us trade in our old engine for credit on the upgrade. Jon Nelson is a real stand up guy and I've got nothing but good things to say about him and his organization.

 

The kit included :

the Zetec with enormous cajones and all the EFI and ECU wiring loom, etc,

A custom exhaust system which lets the tubes exit the body where the old XF ones did and the fattest, most aggressive looking silencer I've ever seen on a production car.

It all appears ready to go, and Jon was kind enough to label almost every loose wire so that retards like us have a good chance of not screwing it up. Especially, when the good folks at BlatChat can fill in the blanks.

 

As far as internal changes to the Zetec, that's out of my realm. I know it's a fairly similar package to the Raceline 200 horse engine, but can't be any more specific than that. Sorry.

[magnusfeuer]

Regarding the Senate Bill 100 and registering kit cars in California: I have a step by step instruction for this process in a Word file. I wrote this to document my DMV adventures with the Caterham.

Mail me at magnus.feuer@wirelesscar.com for a copy.

 

/Magnus F.

 

 

Edited by - magnusfeuer on 3 May 2003 21:27:36

[JamesA]

I have delt with Jon Nelson a lot also and agree he is a terrific person and real source of Caterhan knowledge. I bought my engine and gearbox from him for my SV kit. He recons I have on the order of 175 - 180 HP, but as everyone knows, enough is never enough, so I am looking for 200!

[yankeedoodoo]

Are there any posters/lurkers stateside running the TWM 50mm Zetec setup who might comment on how long the system has been in use and how well it is working?? And are you using a pectel ecu??

[yankeedoodoo]

MF: I suggest that you ask the same question(previous post) on the USA se7ens site to see if there are some opinions on the TWM setup. Nationally there is quite a decent body of 7 knowledge willingly shared on that site.