DHLA 48’s on a 907 engine?

[LOTUSMAN33]

Has anyone run a pair of DHLA 48’s on a 907 engine Esprit?

If so what jetting and tubes have you used?

These came with my S2 esprit and are in excellent condition with no play in the butterfly spindle, if I can use them I will otherwise I will service them and sell on to buy some DHLA 45’s.

My car currently has a new set of Webber’s, not driven it yet or any esprit running Webber’s so will be interested to see how it goes.

The car is standard other than the K&N’s and what will be a Peco sports system removing the intermediate silencer.

Dave  

 

[Barrykearley]

You really need to loose the k&n setup and get back to the original air intake - it really reduces the fire risk

[LOTUSMAN33]

I have been in two minds Barry as my first ever esprit ran these filters and sounded great but as you say increases the fire risk. I have an original filter assembly I got from Matt Watts so will probably fit that.

I will be running an automatic fire system on this car though no matter what.

Dave  

[Barrykearley]

You’ll never beat the sound of them k&n Filters fitted like that - but the woof it makes when they drip isn’t so good

[LOTUSMAN33]

I know you’re bang on but as you say the sound.....

Ive been in a fire once already and caught my hair on fire at the same time....

It went up in seconds not minutes, the roof must have been made of something highly flammable, a taxi driver pulled me out just in time as panic was setting in. 😥

Perhaps I will fit a K&N element to the standard air box.

Dave  

 

 

[yeller77]

Also, WRT the K&Ns, fixation nuts on the inside of the filter are a danger for loosening and ingestion. Hate to admit how I know. :( Some (Garry Kemp) have said 48's are a bit much for a stock or nearly stock 907 and may be difficult to tune especially at idle or low speed. He'd be a good source for such questions.

[LOTUSMAN33]

Thanks Eric, this is what I expected so I may sell them after a service as they seem very desirable on eBay so should easily cover a pair of excellent 45’s.

Ive serviced/rebuilt several sets of DHLA’s over the years and have a nice rig for setting the accelerator pumps.

Has anyone any experience of running the Webber’s, they seem popular on US Esprit’s? 
They seem to be lovely quality bits of kit with smooth operation of the butterflies and chokes.

Dave  

[ekwan]

Webers are fine on a 2.0L Esprit engine, but 48's may be going a little OTT. Not sure if you can fit the appropriate sized venturis on them. You need 36-38mm ventures for a 2.0L engine, but going by the Weber chart this isn't available for a 48DCOE. I believe, it would be the same for Dellorto carburettors.

Personally, I would seriously consider moving onto Weber DCOE's if I ever and the need to rebuild my current DHLA45E's due to the non-availability of factory original parts. I am finding out that 3rd party non factory jets are a tad inconsistent in quality and performance. Besides that, a good re-conditioning job by a specialist is close to £350 whereas a pair of Webers comes to £600 and beats a lot of pfaffing about with cross-threaded screw threads etc.

[LOTUSMAN33]

Thanks Eric, I will give my Webber’s a try once the cars running and if good move on the DHLA 48’s once given a seal change. There’s been a fair few issues raised in various posts over DHLA spares quality recently which is a tad concerning for the future.

Dave  

[Andyww]

Many Lotus Elans have been lost owing to using K&Ns. 

Apart from the fire risk they dont filter. Many years ago I read a proper test report on these and the testers found they did absolutely naff all unless they were cleaned and re-oiled before every trip.

[LOTUSMAN33]

Thanks Andy, well that confirms they will be going and the standard box going back on, I just need four trumpets now... 🙄
I was unaware of the performance or lack as the case may be.

Dave  

 

[ekwan]

Which Webers are on at the moment?

[drdoom]

20 hours ago, LOTUSMAN33 said:

I know you’re bang on but as you say the sound.....

Ive been in a fire once already and caught my hair on fire at the same time....

It went up in seconds not minutes, the roof must have been made of something highly flammable, a taxi driver pulled me out just in time as panic was setting in. 😥

Perhaps I will fit a K&N element to the standard air box.

Dave  

 

 

Mon Dieu !!

 

[drdoom]

20 hours ago, LOTUSMAN33 said:

I know you’re bang on but as you say the sound.....

Ive been in a fire once already and caught my hair on fire at the same time....

 

It went up in seconds not minutes, the roof must have been made of something highly flammable, a taxi driver pulled me out just in time as panic was setting in. 😥

Perhaps I will fit a K&N element to the standard air box.

Dave  

 

 

Mon Dieu !!

I believe the DCOE's can be run quite successfully, given informed treatment. Suggest checking out the development work being done by Keith Franck, of California, link attached. Caution advised with regard to modern day bits from offshore sources as they may be of dodgy quality.

https://vintagetechnologygarage.groups.io/g/sidedraft/messages

 

[LOTUSMAN33]

Thanks Steve I have requested to join that group so look forward to reading 👍🏻
 

Eric, my carbs are 40 DCOE 

Dave  

[drdoom]

40's will run perfectly nicely if properly set up though are likely to limit top end power output. Given the choices I'd run the DHLA's once gone through thoroughly for the sake of ultimate output, would also greatly suit a 2.2 upgrade if that were in the cards. KF has also done work on bits to suit the D'ellortos as they function along the same principles as the Webers. BTW, one keen local chap used to rave about the Triumph Dolomite powered 2 litre TR-7 he drove, tuner equipped with 48DCOE's and 42mm chokes, FWIW.

Cheers 

[ekwan]

I had new 55 idle jets fitted to my DHLA45E's on my 2.2L engine. These were reproductions as the factory no longer makes them. As such, the holes are drilled to a specific size 0.55mm, but they are not flow tested, unlike the factory items so there may be differences in the flow characteristics between individual items, albeit probably negligible differences.

What I found that, with new non-factory 55 idle jets, the exhaust was throwing out loads of black smoke, and the engine runs even when the mixture was full in. Moving back to the old idle jets, or using other sizes that I had in stock, there wasn't any black smoke (or very little) even up to size 62 idle jets (factory items). I suspect the non-factory jets were not sealing against their seats, therefore excess fuel dripping in through the progressions even at idle. Unfortunately 55's aren't available as factory items anymore AFAIK.

[ekwan]

3 hours ago, drdoom said:

40's will run perfectly nicely if properly set up though are likely to limit top end power output. Given the choices I'd run the DHLA's once gone through thoroughly for the sake of ultimate output, would also greatly suit a 2.2 upgrade if that were in the cards. KF has also done work on bits to suit the D'ellortos as they function along the same principles as the Webers. BTW, one keen local chap used to rave about the Triumph Dolomite powered 2 litre TR-7 he drove, tuner equipped with 48DCOE's and 42mm chokes, FWIW.

Cheers 

Did he run a single 48DCOE on 42mm chokes, or 1-barrel per cylinder?

[LOTUSMAN33]

Thanks chaps, some good information, I will get her running and see what it’s like and check out the jetting of the 48’s when stripped as these were on the car at some point. A 2.2 upgrade is a nice thought and a friend is doing exactly that to his S1 at the moment installing a HC engine. 
Dave  

[Clive59]

Just noticed as reading an old piece, the 48's were used on the Lotus Talbot 2.2 dry sump engine, which developed 240bhp. 

[drdoom]

11 hours ago, ekwan said:

Did he run a single 48DCOE on 42mm chokes, or 1-barrel per cylinder?

That was a pair of 48DCOE's on a Dolomite Sprint 16 valve engine prepared by some outfit with full-on rallying spec intended. The owner of my acquaintance drove it strictly on the street.

[LOTUSMAN33]

240 BHP from a Talbot Sunbeam, now that I would love to drive! I had a go in a ratty one around 20 years ago which went well in standard form and sounded really unique in comparison to hatchbacks of the period. So looks like 48’s are good on a tuned 2.2, I think I’ll hang onto them for now 👍🏻
Dave  
 

[Djs44]

I was chatting with Lotusbits yesterday and their 2.5l conversion runs on 45s , putting out 240bhp+..very tempting 

 

Their Sunbeam runs well north of 300BHP ...

[LOTUSMAN33]

Agree they do look so tempting, not cheap but with the feedback I’ve heard the outlay is worth considering I guess. 😎

[Djs44]

I am giving it deep thought as my engine needs a rebuild anyway . 

Would people keep the original engine ( as matching numbers ) and use a new block for a 2.5l conversion ???