Throttle bodies

You can get good power just by giving head so no need to strok'er and that had the same performance as a 33 off the mark....

do you mean a r33? if so, you do get what torque means? I think we're all too caught up on 0-60 times and forget that we're on a classic car forum where feel and sensation are why we're here.

I've a company car that more or less keeps a maclaren f1 honest to 80mph. its great at what it does but its missing 'feel'.
 

Coyd

Well-Known Forum User
Well that was all very enlightening.
There seems pro’s are drive ability, power increase and fuel economy.
Con’s, cost and time fitting
 

status

Well-Known Forum User
Nothing wrong with a good set of 40 s that have been set up properly I think you will find those with strokers tend to go the TB route ,I personally would stick to carbs if it was just a 2.8 and a bit of head work
 

atomman

Club Member
I think the main thing you get i drivability and reliability. Some extra HP is a bonus, but not the main thing, carbs like Webers are really good at wide open throttle.

My car is very nice to drive in regular traffic, especially considering the amount of tuning done to the engine. Took some dialing in, but it's very tame. No bucking, no running unclean etc. It's almost like the stock engine but with more power on low rpms. Then when you get to the racetrack it performs just as well but at 8000rpm at WOT. No problems starting it cold in the mornings etc, it just works! If it's humid or cold, same thing. This can work so well, especially if you pair it with a trigger wheel and coil on plugs. But of course, that's even more money.

I know a well setup DCOE can work reasonably well, but it's not in the same ball park as a good tune with the ITBs.

There is also one more aspect that I like: Safety features. My ECU has built in protection against loss of oil pressure and running lean. My timing can compensate for a lot of problems with fuel flow (you need a modern spark distribution for this though). Then I have a big Lambda value gauge so I can see if I have problems before I melt a piston. These features are worth a lot to me!

I understand that most people don't use their car the way I do, and then it's probably not worth it. If I had a nice street car then I would probably have some Webers on it. It's all about priorities and needs in your specific application.

Same with uniballs, either you need it, or you don't

Thing is my car drives the same as you say above ,and I drive my car hard around the mountains & the odd hill climb but then sat in traffic it just ticks over nice, in all types of weather to..

I have a Lambda in the exhaust and a gauge to see Fuel/air ratio to . I just watch the oil pressure gauge as I don't have an ECU with safety features,

I find most peoples experience of DCOE's or DHLA's are from poorly set up cars and the myth you need to tune them every 5 minutes.

It is harder these days to find a rolling road to tune them properly though , most of them now only understand ECU's and haven't got a clue when they see carburettors. Luckily in Wales there are still plenty of old rally cars that need tuners that understand carburettors so there is a few guys around.

Be good to hear if anyone has run carbs them gone to ITB's and see there power gains and torque curves etc ?

just trying to be devils advocate here. I will probably end up with ITB's anyways, just because I like to fiddle round and should get some more out of my engine , how much extra we will see but is all that extra money worth maybe 20-30BHP ?
 

status

Well-Known Forum User
I went from Delorto 48 s on the 3.1 to Jenny’s ,possible to get an extra 20-30 bhp so I’m told with TBs by people that know more than me
 

peter_s

Club Member
Thing is my car drives the same as you say above ,and I drive my car hard around the mountains & the odd hill climb but then sat in traffic it just ticks over nice, in all types of weather to..

I have a Lambda in the exhaust and a gauge to see Fuel/air ratio to . I just watch the oil pressure gauge as I don't have an ECU with safety features,

I find most peoples experience of DCOE's or DHLA's are from poorly set up cars and the myth you need to tune them every 5 minutes.

It is harder these days to find a rolling road to tune them properly though , most of them now only understand ECU's and haven't got a clue when they see carburettors. Luckily in Wales there are still plenty of old rally cars that need tuners that understand carburettors so there is a few guys around.

Be good to hear if anyone has run carbs them gone to ITB's and see there power gains and torque curves etc ?

just trying to be devils advocate here. I will probably end up with ITB's anyways, just because I like to fiddle round and should get some more out of my engine , how much extra we will see but is all that extra money worth maybe 20-30BHP ?
Sure, I think a set of well setup carbs can work really well too. Thankfully we have quite a few very good rally people here as well, but it's a dying art for sure. I love DCOE carbs, they have a great charm and character, and are really good, no doubt about that.

But also playing the devils advocate here, I think your big argument here is difficult to prove. Yes your car is running great, but you haven't had a ITB setup on your machine to compare with. But that's the case with my car as well! I haven't run my engine on carbs.... so my point is also not the best, although I haven't had one single misfire or hickup yet. I know this is also anecdotal, but even when I've run my car on track at 30degs outside and I park it, I notice nothing going out street driving after a 5 minute break with very high temperatures under the hood. I think the carbs would struggle here, but I might be wrong. I have an intake air temperature sensor so my ECU can compensate for that.

To be honest, I really think a 20-30bhp gain with ITBs is a big stretch. I don't think there is going to be any big difference at all between a 50mm DCOE style carb setup or a 50mm Jenvey. Not at peak power, a well setup DCOE should be able to flow the same really. So I don't really think a big DCOE isn't for a stroker, that's more to do with the right setup and tuning of the carb.

I think the difference is going to be the torque curve in general under the peak power numbers, it's going to be better (hence coming back to drivability). And even if we might argue here a little, I really think the benefits with ITBs, ECU and a fully controllable ignition is highly beneficial and it will produce a more driveable car in more conditions.

But the fact is, which I think is very important to stress that I'm not going to say that ITBs are the way to go. It's all about your needs, preferences and budget. I can motivate my choice by saying that for my application and use, I would make the same choice again. But I would love to build a nice DCOE engine as well. There is no right or wrong here, any ITB setup is great, be it a DCOE or Jenveys.
 

Ian Patmore

Well-Known Forum User
I get what Peter_s says and agree. But, the key to a good DCOE/DHLA/PHH set up is the set-up. It takes time, even if you have right jets, you still may need to use a jet drill to get it spot on, like mine did. Running 48DHLA's, no spitting or hiccup, starts when cold. It's finding the place to the work, and the time and £ spent setting up. There are plenty of things to adjust on these carbs.

Fuel economy probably 1 mile injection better than carb, but my 3.2 does better milege than the 2.6 that used to be in it. All depends how you drive it and how the engine produces its power/torque.

Jenveys, my friend has them, they are cheap and nasty, thin bodies, just not made well from what I see. As someone else says, they do the job.

Would I go ITB's, maybe, but it doesn't out weigh the cost/eye candy, for a few more horses/mpg. Definately not Jenveys if I did.
 

Herc34es

Club Member
This is a very very interesting thread to follow. There are some terms that I am not familiar with (sizes of ITBS).

So the gist of the thread is to avoid Jenveys (heritage). FI easy to set up than all the rest. (I took out the FI from mine as the old unit was toast). So which ITBs are a good recommendation to install? (I have seen the suggestion from jonbills but the ebay ad no longer exists)
 
Last edited:

status

Well-Known Forum User
Go with those that have experiance with the jenvys,had mine on since 2005 and never had a problem ,im running a porshe fuel pump,Vauxhall coil packs, and a few other tricks,best stick to wots been tried and tested also wot motor 2.8 3.1 etc,ignore those that comment and don’t run TBs as experiance counts for everything
 

Herc34es

Club Member
Silly question on ITBs... the trumpets, where the air goes through to the engine right...don't they need an air filter? what if the environment is very wet or hot dusty /or by the beach etc? Does that affect the ITB performance at that time (and long term)? I saw from searches that grime/dirt would accumulate there and I know, even though I am a total noob, that any contaminant is a no-no to entering the engine.

Is the solution to that an airbox (like the one offered some while ago)? I mean another more "permanent" solution compared to frequently cleaning it. If an airbox is installed does that reduce performance compared to having them free, or is the diff is negligible? I am very curious and sorry if I am diverting a bit the topic.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
here's a new link https://www.ebay.co.uk/itm/325268014743
get in touch with them and ask for a discount on 3.
And the same thing with a massive discount on AliExpress

£117.35 26% Off | SherryBerg 40/42/45/48/50 DCOE Twin 40mm 42mm 45mm DCOE Throttle Bodies Body for Weber/EMPI/FAJS/Dellorto/Solex DCOE/DHLA Carb

I only thought to look there as I was thinking about experimenting with different length trumpets a couple of years ago - which gets expensive fast and found sherryberg on AE at a fraction of the cost elsewhere.

Ended up modifying fully radiused DCOE trumpets in the end ;)

44E2157D-DF45-4782-8439-5D9C61319D2F.jpeg
 
Top