Improving your IDA´s...

[Bruce]

My guess is that this new aux vent is the same height as the original one at it's OD, so that the stack clamps it just like stock.

[Zach Gomulka]

Ohh, that's right. The stack holds it all in

[JS]

Errrr... not exactly. Now the venturie just "sits there", held by a tight fit and gravity... Doesn´t seem to go anywhere though.
I sent them back to JPM now for some o-ring machining to ensure a 100% airtight seal between the venturie and the carb body.

Also for the JPM Dyno Day 15th of october Johannes will have completed his new larger diameter "Raptor" stacks. We will flow the carbs there before and after to see the improvement.

[DWL_Puavo]

With custom made venturis, could there be some kind of performance gain from machining the whole IDA body to a slight cone shape? Idea here to continue the cone shape of velocity stacks, not being the only "straight" part on the "port-manifold-carburator-stack" -path?

I was going to check these venturis out in SCC on saturday evening when JS told me I would be surprised, but I found myself to busy playing Black Sabbath's Paranoid horribly wrong with an out-of-tune ukulele...

[nicolas]

I found myself to busy playing Black Sabbath's Paranoid horribly wrong with an out-of-tune ukulele...

wow! nice combo


as for the new JPM vents, they look really good, i hope to see some figures from the dyno day soon. has anyone also done some work on the butterflies to improve there working? i know someone who has/was going to trim the screws to have a greater and evener flow, but havent heard about that since and don't know if it would improve something?

[JS]

Nicolas, I seem to remember at JPM´s flow bench, trimming the screw ends on the butterfly shaft improves the flow through the carb by 2cfm. And that it equals 5cfm at the valve.

Who would have thought?

[Bruce]

I recall a number of years ago Deano did a small article for hotVW's that included flow bench results of profiling the throttle shafts of IDAs.  I don't remember the results.  Perhaps Deano will speak up?

[JS]

Well, it seemed my car chose to not perform ideally on the sticky Gardermoen track. Need to work on my chassis setup.
I got at best a 1,7 60ft. ETs over the weekend was in the 12,1-12,5 range with the best ET on the last run 12,18 if memory serves me correctly.

I was ref to back to back time slips.before and after you made the changes on the prototype venturies.. Sorry, If I miss-lead you..

Finally went to the workshop to check some time slips. It seems the best ever top speed on the car was 176,9kmh. This was actually on saturday at SCC this year. The day after I made the the 180,4kmh pass. The best pass ever on the car is a 11,95/174,95kmh. But different weekend and track.

[Torben Alstrup]

A name comes to my mind, annular discharge venturi.
Held in place by the same spring-clip as the regular one, I guess. No need to invent new way of doing it?

Only old farts remember that Fredric. - I guess I´m getting old too 

Yes, it is actually, or at least partly a thing from the aviation world. It´s going to be really interesting to see what the difference is in flow and IRL.

T

[Frallan]

Only old farts remember that Fredric. - I guess I´m getting old too 

[/quote]

Yepp, I built three seaters airplanes for SAAB / MFI in Malmö at same time I built the first VW racer.
It was 1977.
In 1978-80 we even raced at the Bulltofta racetrack. That was nice.
Something like 33 or more years ago. Now I was verrry young boy at the time so I am not old yet.....old fart maybe :-)

[markvo]

Gene Berg Ent. has done alot of work on profiling butterflies and throttle shafts on IDA's 1-714-998-7500

[DKK Ted]

I recall a number of years ago Deano did a small article for hotVW's that included flow bench results of profiling the throttle shafts of IDAs.  I don't remember the results.  Perhaps Deano will speak up?

As Mark said above, Berg (Andy) RIP, made these profile butterflies and shafts. Andy made me a pair of profiled shafts and butterfly's, very nice work, very sleek. For screws he used Button Head screws, It all worked. There on my Spanish IDA's now. Contact Berg, I believe they still can do it. All worth it.

Ted

[JS]

So we finally got to see a live flow test on JPM Dyno Day. The gain by switching from a "conventional" venturie to JPM´s vents and stacks was 19cfm!
The size was 42mm both on the old and new.

Some pics here: http://cal-look.no/lounge/index.php/topic,16798.0.html

[Dano382]

Whats the price on the vents and stacks? Did he have any polished or just the black coated ones.   

[JS]

No polished parts from JPM... The upside is that the finish is so good that polishing should not require too much work.
I believe the price is 2995 SEK for the vents and 2195 SEK for the stacks. That should include 25% Swedish VAT.

[Dano382]

So my U.S. price would be $732 dollars, plus shipping. how much cfm increase from vents. What other bennefits from these? Very interested......
Thanks......

[JS]

Call Johannes at +46 4215 08 09 or email him at info@jpmotorsport.se , I´m sure he´ll help you out.

[bilboa2]

I agree Mark Vo as the bergs do it well. My 48 ida's where done there with great results.Reasonable price too. Also try a serdi valve job while your looking to increase flow #'s. oh yeah , 88 stroke kinda helps too.  RIP Andy.. bill

[Lids]

if you trim one trumpet, doesn't this create an airflow difference from the other 3?  Or is it so small we don't notice it when driving?

[Jesse/DVK]

Just like the engine lid will disrupt the flow when it covers half the inlet.

[Taylor]

You can make over 240 HP with a bone stock IDA and a 42mm choke. Spend the money somewhere else.

[BeetleBug]

You can make over 240 HP with a bone stock IDA and a 42mm choke. Spend the money somewhere else.

Yes you can but the JPM IDA modification makes 12-14 cfm more over ALL the revs and not only at the peak.

[Taylor]

You can make over 240 HP with a bone stock IDA and a 42mm choke. Spend the money somewhere else.

Yes you can but the JPM IDA modification makes 12-14 cfm more over ALL the revs and not only at the peak.

How do you know that?  On a flow bench it is Wide Open and under no load.

[BeetleBug]

How do you know that?  On a flow bench it is Wide Open and under no load.

It was tested and proven at the JPM dyno day. Both on the dyno and on the flow bench.

[Udo]

Nicolas, I seem to remember at JPM´s flow bench, trimming the screw ends on the butterfly shaft improves the flow through the carb by 2cfm. And that it equals 5cfm at the valve.

Who would have thought?

I had a broken shaft after doing this , so i like  more to get the flow from the heads  

Udo

[Taylor]

How do you know that?  On a flow bench it is Wide Open and under no load.

It was tested and proven at the JPM dyno day. Both on the dyno and on the flow bench.

How was it tested on the dyno?  first stock and then you took the carbs apart and put the vents minus aux back in and repeat?  what were the results? 

[bilboa2]

taylor, ok, where would you spend the money ( $ 400 ) than simply unbolting the carbs and getting such hp results ? yes, Good heads may net better results, but most here have good heads and you would have to tear motor down for most other improvements. Call mark  @ bergs for results/testomonies. bill

[Udo]

The question is about what hp you are talking about. Last week i changed conventional done 51 carbs to some that where a little bigger on the intake. 2,3  230 hp engine , no diffenece both 44 venturies . Also i had up to 275 hp with those simply done 51's on my 2,5 engine. then i changed to 58 and got 15 hp more....

Udo

[JS]

Well, for some it doesn't matter..

If it´s tested on the flow bench, the bench was probably out of calibration, and the person doing the work was doing it all wrong.
If it´s tested on a dyno, the dyno was probably badly calibrated and thereby giving false results.
If it´s tested on the strip and ends up giving you more top speed the photo cells on the top end were placed in the wrong place, giving you false results.

Each to his own. There´s many roads to Rome.

[Zach Gomulka]

How do you know that?  On a flow bench it is Wide Open and under no load.

It was tested and proven at the JPM dyno day. Both on the dyno and on the flow bench.

What were the (before & after) dyno numbers? What was the engine combo?