Author Topic: The tuning thread  (Read 532 times)

Offline 94touring

The tuning thread
« on: October 16, 2018, 01:37:22 PM »
I'd like to split off my build thread which has now finished up and dived into the tuning phase.  This week I plan to examine the "vizard mods" as done to carburetors.  Since I have my wideband installed I can now see if any of this stuff actually makes a difference.  I intend to put together a graph and hit the salt flats of Oklahoma (long straight flat road by my shop) and chart air/fuel pre and post carb mods.  I will start at 20mph and increase in 10mph increments till I hit 80mph, then record a WOT run from 2k up to 6k.  I will gather average air fuels at each speed and chart the WOT run, do the mods, and record my findings post mods.  Do we have any guesstimates?  I also have carb springs and some more dashpot oil test to look at.

Coming up soon once I manage to buy the correct sized parts, will be an ITG huge foam filter setup.  Then shortly after these mods are complete I'll test a 60k volt coil and some different style plugs that the intranets and youtube clips show dyno results in the positive.  For that test I will hit the dyno to try ngk plugs vs this brisk style plug.  This will also show results from the vizard mods and give me my final dyno numbers.  Can I hit 85 to the wheels??

Offline MPlayle

Re: The tuning thread
« Reply #1 on: October 16, 2018, 02:34:03 PM »
That would be a gain of 6hp at the wheels?  So a gain of 8 crank hp needed?  Should be reachable.


Offline 94touring

Re: The tuning thread
« Reply #2 on: October 16, 2018, 02:42:23 PM »
A gain of 5.7 to the wheels  ;D

Offline 94touring

Re: The tuning thread
« Reply #3 on: October 17, 2018, 02:01:44 PM »
Matching the ports a little better.  There was a pretty significant sharp lip along the bottom half where the manifold met the head.

Offline MiniDave

Re: The tuning thread
« Reply #4 on: October 17, 2018, 02:08:39 PM »
Are you grinding on the head or the manifold - or both? How are you keeping the shavings and dust out of the engine?
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: The tuning thread
« Reply #5 on: October 17, 2018, 03:35:53 PM »
The head only, as that's where the lip is.  Blocked off the ports, stuffed with gauze and Vaseline to catch shavings, then thoroughly vacuumed and inspected.

Offline 94touring

Re: The tuning thread
« Reply #6 on: October 17, 2018, 05:14:04 PM »
Ended up taking a bit more off the top and each side.  I needed to put on a new gasket when it was all said and done.  The new gasket was better suited for a big bore engine and worked better as a template.  I simply put about a 45 degree bevel leading into the ports.  Would have been much easier had I thought of this pre install.  Nonetheless, I would have to think eliminating a sharp lip the whole circumference a solid 1/16 wide should make an impact.  I also gave the butterflies in the carb some work.  Going by the yellow vizard book I cut the top half of the shalfs off and then levelled the screws with the remaining shaft.  The book gives some increased cfm figures out of the deal, so I'm curious to see how the car reacts.  Also knife edged the butterflies a hair per the book.  I have air fuel ratios I logged today for each speed and full throttle run.  Now I just need to compare.  80mph is lean I discovered at 16:5, but that will be an easy fix.

Offline 94touring

Re: The tuning thread
« Reply #7 on: October 18, 2018, 12:34:26 PM »
The butterfly and port matching made a big difference.  Nearly 1:5 leaner on average at any given point during pickup and cruise from idle all the way to 70, where it was too lean to drive.  WOT wasn't effected nearly as much.

Offline 94touring

Re: The tuning thread
« Reply #8 on: October 18, 2018, 05:58:26 PM »
Did a full days worth of needle and mixture fiddling.  With the carb and port work I had to refile a lot.  After getting it in the ballpark I took my calipers and measured out each station and found a needle closest to what I've created.  Wouldn't be a big deal on a single carb but having twins and the amount of needle adjustments I made, probably best to get new for consistency. 

Offline MiniDave

Re: The tuning thread
« Reply #9 on: October 18, 2018, 06:13:21 PM »
What number did you come up with?
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: The tuning thread
« Reply #10 on: October 18, 2018, 06:25:48 PM »
Closest match is ADX.  WOT station slightly richer, low speeds slighter richer, but 40-80mph stations progressively rich.  This being AAK pre filed vs ADX.  I really had to file a ton in the 70-80 range.

Edit: changed it up and went with AAM after dissecting the needle book.  Ironically 7ent list it for a kent 266 cam. 
« Last Edit: October 18, 2018, 10:01:57 PM by 94touring »

Offline 94touring

Re: The tuning thread
« Reply #11 on: October 19, 2018, 10:03:41 AM »
More research.  Found where Calver had some needle profiles for twin hs4s on the Kent series cams along with head work and moderate compression motors for the street.  K&N filters ect...  He list the AAM needle and an AAA needle, both on my radar as far as matching what I had created.  The AAM was more suited for a 286 cam while the AAA a 276.  The needle he chose for the 256/266 cam was very lean up top and didn't seem to be in the ballpark at all.  I tossed in the AAA needle for good measure to see how it does. 

Offline 94touring

Re: The tuning thread
« Reply #12 on: October 26, 2018, 07:51:11 AM »
Tossed in the Aam and Aaa needles yesterday based off my new profile. Cruising air fuels were dead on the money, specifically on the Aam.  But WOT was too rich for my liking, at least to get max power.  Have a couple other sets to try that may work better. 

Offline 94touring

Re: The tuning thread
« Reply #13 on: November 10, 2018, 09:20:07 AM »
Spent yesterday fiddling with needles and carbs.   A set a AAV and AAS arrived.  Calver recommended the AAV on twin hs4 with my cam but I was skeptical they'd work on my setup given the intake work.  I put the AAS as an option as the profile cruises much richer in comparison and has a roughly same top end profile as the AAV.  My filter box setup isn't the easiest to get on and off, which is required in order to set the jets.  I would put the box on temporarily using one bolt to secure it well enough while I could make a tuning run, note air fuels, come back, pop off the filter box, adjust jets, box back on, repeat.  It was time consuming.  What I found was the AAS was a vastly better match and aside from being a tad rich at idle and pickup, worked really well...till I tightened the air box all the way down and the ram pipes worked more effectively.  As it turns out having just a slight gap between the ram pipes vs securely fit makes a big difference at top end cruise and WOT.  I couldn't richen the jets further as idle and pickup just wouldnt work.  Most of the profile was really close other than 70-80 cruise and 5k-5500 rpms WOT had a big lean spot.  Pre air box tighten the air fuel in that area was around 13:1, post air box tighten it went to 14 and some change.  Back to filing needles it was.  Didn't shave much off on the upper stations but was able to bring things down into the upper 12s lower 13s with a bit more needed in that 5k to 5500 range still spiking to 13:6 or so, then by 6k it was back to 13:1.  Ran out of time but next week will work the top stations some more, working my way down the needle to pinpoint the 13:6 spot.  The 70s at cruise is still a hair lean too but I think it may be running off the same station I'm targeting for WOT given the rpm range.  I will say it pulls much harder going from 11s air fuel to upper 12s low 13s air fuel.  More next week.

Offline John Gervais

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Re: The tuning thread
« Reply #14 on: December 06, 2018, 05:22:23 AM »
- Pave the Bay -

Offline MiniDave

Re: The tuning thread
« Reply #15 on: December 06, 2018, 10:14:57 AM »
John, I downloaded Office Libre, where is the link to the needle comparison program?
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline tmsmini

Re: The tuning thread
« Reply #16 on: December 06, 2018, 10:18:39 AM »

Offline 94touring

Re: The tuning thread
« Reply #17 on: December 06, 2018, 02:42:54 PM »
I will definetly check that out from my computer at home!

Offline MiniDave

Re: The tuning thread
« Reply #18 on: December 06, 2018, 02:47:11 PM »
I couldn't get the zip files to open, but back in the day when MintyLamb had his up it was a really valuable tool - he's supposed to be updating it into a web friendly format, but that's been about 2 years now....I'm not holding out much hope that it comes back.
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline tmsmini

Re: The tuning thread
« Reply #19 on: December 06, 2018, 02:59:22 PM »
You should be able to extract the files from the zip.
I will try to attach them separately. It is a pretty good tool. I think Burlen has it on the SU site as well.

Offline John Gervais

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Re: The tuning thread
« Reply #20 on: December 06, 2018, 03:36:30 PM »
The last time I spoke with Ian, he'd just come back from a meeting with Berlen Fuel Systems and they were very impressed with his comparison tool.  I suspect that the reason it's not on their website is that there's simply too much information available and it's not something one can 'master' in a few minutes.

The aspect I appreciate most is the 'Advanced' page - it allows one to compare a standard needle profile on the left to one on the right (can be the same needle) and either raise or lower the jet on the 'right' needle OR 'file' various positions on the 'right' needle.  This way one can simulate the change in annular area of the needle on the right without investing in or damaging a needle.  One can also compare 0.100" needles to 0.090" if one wants to install the 'incorrect' jet to get more precision in corrected fueling without filing needles.

Attached you'll find a comparison of 3 standard needles to a 'modified' AAA.  Taking a moment, you'll see the % change in annular area as well as the new physical dimensions of the AAA - should you want to lathe your own.  (This .jpg is an assembly of 3 separate screenshots)

Also, a standard AAA vs. a 'modified' AAA - this one has a bit more highway cruise fueling.

An MME fixed needle vs. AAA - particularly useful if one has a pair of fixed-needle pistons and wants to use or compare a swinging needle.

And so on...  Extremely versatile, and it's more relevant to carb function than mintylamb because it utilizes the 'actual gap' between the jet and the needle (which allows fuel to be sucked into our hungry cylinders) and not the static needle dimensions.
« Last Edit: December 06, 2018, 03:40:18 PM by John Gervais »
- Pave the Bay -