Topic: H8PVMNT's Aisan 22r Carb Tech /Study

[H8PVMNT]

I had been adjusting the ignition timing as I went.  As you adjust the cam timing the position of thing is as such with the distributor drive gears, I think it's 2:1 but I can't think right now, that you end up with a fairly large adjustment to you ignition timing.

So what I found is that as you adjust cam timing you accidentally adjust your ignition timing, but it won't necessarily change where you want your ignition timing to be relative to the crank, if that makes sense .

I have been running my ignition timing differently as I tune depending on what feels right and doesn't ping.  I think I have ended up at like 7-8 degrees BTDC these days.  Much more than that and I end up bumping into pinging with 87 octane.

[H8PVMNT [OP]]

Tried the clear line and the AAP was leaking.  I replaced it with a fresh one I had in a rebuild kit and now it runs terrible!  Maybe the new one leaks more, I don't know.  I'll have to get back to you on this...

Alright so after a few creative explicatives I put the clear vac line back on and there was no fuel, so the new AAP was good.  Then I thought the float or the float valve might have stuck, which is nearly impossible, but all I could think of...  Took the carb top off and it was fine.

Then I started thinking it was running like the fuel cut solenoid was bad.  It wouldn't idle unless I bumped the idle speed way up and then it was really stumbly.

I ran out of time and had to go out to Dane's to pull Mudder's 3RZ.  I tried to roll up my back window, but it wouldn't work.  My heater blower didn't work either!  I realized I had somehow blown a fuse to one of the big deal relays.     Replaced the fuse and everything runs fine now. This was a classic example of how whatever the issue it it's more often than not something stupid.

[H8PVMNT [OP]]

After replacing the AAP and running a while I am back up over 13 mpg Yippy.    Seems to be 13-15 mpg is where I am going to be with this carb.  I may go off on a research tangent here soon looking for more economy...

OK here is my tangent:   http://board.marlincrawler.com/index.php?topic=101980.0

[H8PVMNT [OP]]

22r carb back on with fresh AAP and a few minor adjustments.  Adjusted butterflies to open the secondary a bit later. Still hovering around 13 mpg.  I have done better, but jetted and adjusted for decent performance this seems to be where we end up at my elevation on typically set up 4Runner.

Jake will be rebuilding his carb from his '83 pretty soon for school.  We will post that up.

[H8PVMNT [OP]]

So what have we learned?

1)  You can adjust and re-jet the 22r carb, to a point.

2)  The Aisan 22r carb can be made to breath freely and offer better response and acceleration.

3)  We can take nearly everything off of the carb and even run a manual choke, and they still work.

4)  Performance will be at the sacrifice of some economy.

[Gnarly4X]

H8PVMNT,

Have you ever weighed your Runner?

Gnarls.

[H8PVMNT [OP]]

Been a while, but I plan to get it on some scales soon.

[H8PVMNT [OP]]

So another thing to address is what does it cost to get the Aisan carb rebuilt, tuned and breathing well?  I have been dinking with this over a long period of time so I didn't really think about it.  It's easy to imagine that this carb if free, since you probably all ready have one, but let's be real about it shall we?


A selection of main jets:  http://www.jetsrus.com/a_jets_by_carburetor_type/jets_hitachi_main_4H7.html

I got a selection of about 6 jets for about $20


LCE 22r carb to 5 1/8" filter adapter:  http://www.lceperformance.com/Aisin-22R-Carb-to-K-N-Filter-Adapter-Kit-p/1033003.htm

This is a nice piece, although you will have to improvise gaskets.  It was about $50 shipped.


Air filter:  https://www.amazon.com/Mr-Gasket-1487-Easy-Flow-Cleaner/dp/B00068OK9S/ref=sr_1_1?ie=UTF8&qid=1494626353&sr=8-1&keywords=Mr+Gasket+1487

This was about $25.  I cheaped out on this piece and wanted to use paper filters anyway.  Napa has a replacement filter that fits in this one for like $7.50 too.


I used the Napa rebuild kit which was around $60.  Prices vary but I found it to be a good kit.


Manual choke kit:  https://www.amazon.com/Dorman-HELP-55101-Choke-Conversion/dp/B000CO7CK0/ref=sr_1_2?ie=UTF8&qid=1494626569&sr=8-2&keywords=Manual+choke+kit

About $10.


You are going to need some solvent, pinesole works too.  I recently used one of the 1 gallon paint can dip tanks with the basket for like $22.

And some cans of carb cleaner, about $20 worth in my experience.

Fresh vac line and some vac fitting plugs.  I would say another $20 here is realistic.

A small brass wire brush is a must, $3.00 .


Finally when re-building a carb, the best thing to have is an extra carb or two.  They can be in pretty bad shape, you just need them for little parts and for reference.  Lets say you picked up a couple from someone who got half way through a rebuild, in a spider filled box off Marlin forum for $20, that realistic .


So I think that's about it...

Jets        $20
Adapter  $50
Filter      $25
Car Kit    $60
Choke     $10
Solvent   $42
Brush       $3
Vac Line  $20
Spares    $20
            $230

Total for a stripped down, performance tuned, aisan carb that makes your truck go faster and works well at all angles, not including your time.

I am going to say there are some unseen incidentals in here, you used a bunch of mama's paper towels, wrecked a t-shirt and a pair of jeans.

Safe to say this carb costs about $250 to get to this point.

[Plainview]

This is a great thread!  My Weber 32/36 is pissing me off so think I'll play around with the old Aisin and see how it stacks up.

Couple questions/thoughts about airflow and CFM ratings.

What is the basis for the formula you use to calculate the airflow demand of your engine?  I found the same formula online but not sure how the numbers are arrived at and no time to research at the moment.

CFM ratings of carbs are usually determined at a specific pressure drop.  Different manufacturers may use different numbers.  I wonder what Aisin uses?

I gathered from the posts in this thread that your engine has a 20R head and an aftermarket cam...?  Do you have a link to your engine build? 

Thanks!

[emsvitil]

The standard pressure drop is 3.0 in water for 1&2bbl carbs   1.5 for 4bbl

[Gnarly4X]

I am no flow expert by any stretch, but just looking at some advertised specs and generally accepted SAE testing, and the data from my Engine Analyzer....

The actual engine CFM for a 22R with 20R head increases with RPM through a range starting at approximately 40 CFM at off idle to about 200 CFM at 5000 RPM.

The test method used to determine the CFM rating of the Aisan carbs is probably the SAE or JSAE International specifications.

The Toyota stock 22R carb will flow about 326 CFM.  A stock Toyota 22R head will flow between 130 CFM.

So the carb will flow more than the engine and way more than the head.

The exact test procedures used for carb and head CFM number are generally not considered accurate enough to apply any real value other than for establishing a base requirement.

Most manufacturers for the consumer automotive market probably design the CFM ratings to meet average RPM use and meeting with EPA emissions standards.

There can be a number of variables when testing flow and CFM… for example:  dry (air) or wet (air+fuel)? At what barometric pressure, ambient air temperature, inches of mercury?

On an engine dyno some carbs might flow more than the manufacturers rating, some might flow less.

Other than a flow bench, AFR tuning and dyno testing is a good way to evaluate best flow performance - depending on your target goal.  For average DIYers, jet tweaking and butt-dyno testing is another way.

If you knew the formulas, test procedures, and all variables, what would you do with that data?

Gnarls.

[emsvitil]

Here's another thing to do: (I did this when adjusting the carb for my motorcycle)

You need an AFM meter (at minimum use narrow band O2 with voltage graph)





See if you understand the carb circuits by predicting what would happen when you make a change (idle, jets, etc.)  and use the AFM meter to see if you're correct...........

[Plainview]

...  A stock Toyota 22R head will flow between 130 CFM.

So the carb will flow more than the engine and way more than the head.

...
If you knew the formulas, test procedures, and all variables, what would you do with that data?

Gnarls.

Isn't that 130 cfm per port/cylinder?  If so, then the engine can still flow 200+ CFM assuming a minimum of 85% VE at 5000 RPM.

As to the second question I quoted:  Geek out.  It's what I do.   

[Gnarly4X]

Isn't that 130 cfm per port/cylinder?  If so, then the engine can still flow 200+ CFM assuming a minimum of 85% VE at 5000 RPM.

As to the second question I quoted:  Geek out.  It's what I do.   

Hey Plainview,

I enjoy learning and getting into technical discussions, however getting into the weeds on head design will go WAY beyond my very basic current knowledge or experience. 

Head design, cfm, flow and velocity are generally considered to be THE most important engineering design aspects of any engine where high RPM performance (race applications) or volumetric efficiencies (street) are targets.

So you’re a “flow geek”?

Are you asking if 130 cfm is the flow per port?  Do I assume you are referring to the intake ports?  Then,  doing the math, 130 times 4 equals 520 cfm, right?  Using your 85% VE figure - that would be 85% of 520 cfm which equals 442 cfm, right?

Can you please explain where you get the numbers?

Thanks,

Gnarls.

[Plainview]

The only numbers I have are what have been thrown about in this thread.  I have no idea what a 22R or 20R head flows.  I saw your post above where you mentioned 130 cfm, which I can only assume is an intake port...  I'd find it hard to believe one of these ports flows less than that.  I've never seen any flow data on a Toyota head.

I'm actually kind of surprised by this.  Toyotas have a pretty big following, the 22R/E is an extremely popular engine, they made millions of them, and there are a lot of people still building and modifying them today.  That someone hasn't plopped one of these heads on a flow bench and published the results is, well, confusing.  Maybe slightly less confusing is the idea that someone has indeed done this and my lame google-fu just hasn't turned it up.  Links welcome!

In my other life, which consists of old American musclecar performance, my preferred cup of tea is Pontiacs.  A Pontiac V8 hasn't rolled off the assembly line since 1981 and those were the lame 301s that no one cares about.  A desirable Pontiac V8 hasn't been produced since '78 and yet there is tons of data out there about those engines.  Lots of people have flow tested factory heads in both stock and modified forms and published the results.

The engine airflow demand equation is one that H8PVMNT posted and I also found it on the web when googling "engine airflow demand."  I don't know where or how the constant in that equation is derived, thus my question above.

I'm just a bit geeky about engine performance and I'll pursue design questions & performance parameters as far as I think it makes sense to.  I understand a lot of the basics about how port volume, cross section, valve sizes, etc. play into performance *in general* but I'm not an engineer, just an enthusiast who likes to understand the math and the logic behind the story he's being told.

With the 22R/E we're dealing with a ~150 ci engine.  Unless there's something about the design of the heads that prevents it, I'd think it should be easy to get into the 125-140 horsepower range with these engines and still enjoy good cold starting, low speed drivability, and broad torque bands.  Or maybe the heads just suck, along with the commonly available piston designs, and wishing for more than 120 HP is a fool's dream...?

[Gnarly4X]

Great discussion...  and I don't mean to go off on a tangent from H8PVMNT's main topic.

- Plainview - The only numbers I have are what have been thrown about in this thread.  I have no idea what a 22R or 20R head flows.  I saw your post above where you mentioned 130 cfm, which I can only assume is an intake port...   I'd find it hard to believe one of these ports flows less than that.  I've never seen any flow data on a Toyota head.

So the mathematical formula for an IC engine flow cfm is well known, but it’s theoretical. The variables involved in actual cfm flow are very complex and very difficult to accurately analyze. Changes to any component in the engine – head ports, intake, valves, pistons, compression, exhaust, fuel, etc. cause an affect, either predictable or unpredictable, and every engine design can be affected differently by those specific changes.  Just because you bolt on a 600 cfm Holley 4-bbl double pumper on 307 Chevy SB that had a 250 cfm 2-bbl Rochester, does not mean you will suddenly see a power gain. Most of the published data on this has been for the “race” community, and as you say, mostly during the early carb’d muscle car era. Obviously testing for performance increases in a race engine that are typically designed for WOT over sustained periods is WAY different than the daily driver, fuel mileage, maintenance, and emissions compliance are key design considerations.

- Plainview -
I'm actually kind of surprised by this.  Toyotas have a pretty big following, the 22R/E is an extremely popular engine, they made millions of them, and there are a lot of people still building and modifying them today.  That someone hasn't plopped one of these heads on a flow bench and published the results is, well, confusing.  Maybe slightly less confusing is the idea that someone has indeed done this and my lame google-fu just hasn't turned it up.  Links welcome!

 I agree, I’m not sure why that test data appears to be so secret.

- Plainview - In my other life, which consists of old American musclecar performance, my preferred cup of tea is Pontiacs.  A Pontiac V8 hasn't rolled off the assembly line since 1981 and those were the lame 301s that no one cares about.  A desirable Pontiac V8 hasn't been produced since '78 and yet there is tons of data out there about those engines.  Lots of people have flow tested factory heads in both stock and modified forms and published the results.

Back to my comment above.

- Plainview- The engine airflow demand equation is one that H8PVMNT posted and I also found it on the web when googling "engine airflow demand."  I don't know where or how the constant in that equation is derived, thus my question above.

Here’s one link that describes the formula…  http://www.widman.biz/English/Calculators/CFM.html

I'm just a bit geeky about engine performance and I'll pursue design questions & performance parameters as far as I think it makes sense to.  I understand a lot of the basics about how port volume, cross section, valve sizes, etc. play into performance *in general* but I'm not an engineer, just an enthusiast who likes to understand the math and the logic behind the story he's being told.

Me too.

-Plainview- With the 22R/E we're dealing with a ~150 ci engine.  Unless there's something about the design of the heads that prevents it, I'd think it should be easy to get into the 125-140 horsepower range with these engines and still enjoy good cold starting, low speed drivability, and broad torque bands.  Or maybe the heads just suck, along with the commonly available piston designs, and wishing for more than 120 HP is a fool's dream...?

Right… at .060” overbore from stock, the 22 is about 150 CI.  I believe that the increase from factory stock to 125-140 HP is possible and fairly easily done with a 22R. BUT… with the 22 EFI, it is not as easily done, and requires much more tweaking and careful selection of components and changes. For example, I don’t know what MommaECU will “allow”?  It’s been stated that the stock 22RE injectors will only pump about 125 HP worth of fuel?

The reason I’m curious about compression is because I very seldom see any data on this after a rebuild.

A displacement change (overbore) and a reasonable increase in compression, with a mild change in a cam profile, on top of a ported head, added torquey header and slight increase in exhaust flow, it’s my belief that we should be able to see and dyno test an increase in torque and HP numbers that will be very noticeable and still allow the 22RE to have reasonable fuel mileage and excellent driveability.  But… I may be dream’n.

Gnarls.

[emsvitil]

I did this a while back to visualize the flow requirements of various cylinder engines.

The lower the cylinder count, the more you need..............  Flow requirements are based on peak flow for low cylinder counts.

This is for a 6 cylinder.      peak and total are about the same.      For above 6,   total comes into play; as more than one cylinder is pulling from the carb at a time.    Below 6, you use peak flow.

My rule of thumb is to take the volume of 1 cylinder, then multiple by 6 to determine carb size for engines with 6 and below cylinders.

[Gnarly4X]

For me, flow bench testing, for either cylinder heads or carburetors, is perhaps the most mysterious engine performance enhancement efforts to be commonly done to increase power – most typically in race applications.  Most of the results and the data would not mean very much to most people who are not flow experts and highly experienced in flow testing on a quality flow bench.

After establishing a baseline test for cfm and velocity for a given intake port on a head, then doing the magic porting or polishing is often considered as much an art as it is a science.  There are most likely many hours of trial and test time and the actual results can only be accurately determined by dyno testing.

Increasing flow or cfm to gain power (torque and HP) by changing a cam profile is somewhat predictable.  Increasing the size of the intake manifold, valves, and adding a larger carb, then adding an exhaust header with opened exhaust, are also predictable.  All are, more or less for many of us average DIYers, the basic modifications.  To determine the results of those modifications, we can test with our butt-dynos, look at the spark plug color, or have your reputable local speed shop chassis dyno the vehicle BEFORE the modification, then chassis dyno test the vehicle AFTER the modifications.

That’s just my opinion – it may be worthless.

[H8PVMNT [OP]]

Golly gee wiz, I take a few days off and you guys go nuts! 

[H8PVMNT [OP]]

This is a great thread!  My Weber 32/36 is pissing me off so think I'll play around with the old Aisin and see how it stacks up.

Couple questions/thoughts about airflow and CFM ratings.

What is the basis for the formula you use to calculate the airflow demand of your engine?  I found the same formula online but not sure how the numbers are arrived at and no time to research at the moment.

CFM ratings of carbs are usually determined at a specific pressure drop.  Different manufacturers may use different numbers.  I wonder what Aisin uses?

I gathered from the posts in this thread that your engine has a 20R head and an aftermarket cam...?  Do you have a link to your engine build? 

Thanks!

OK you asked for it...  http://board.marlincrawler.com/index.php?topic=97297.0

I started with a fresh stock 22r setup and swapped a 20r head and an adjustable timing gear this winter when my cheap aftermarket head gasket let go.  Cam is a stock 22r/re profile.  Fiddling with the cam timing did make noticeable changes in the seat of the pants driving experience.  I highly recommend an adjustable cam gear.

There is a lot of living in that thread.  You will see the more recent engine changes in the post from about January 17 on.

CFM formula is just the standard one floating around on line and on carb websites.  Not sure it it's correct, the 20r carb experiment I did would suggest otherwise .

[H8PVMNT [OP]]

Our buddy fireitup is doing a nice carb rebuild/cleanup thread with lots of pics. 

Here is that thread:  http://board.marlincrawler.com/index.php?topic=102038.msg1141517;boardseen#new

[Plainview]

OK you asked for it...  http://board.marlincrawler.com/index.php?topic=97297.0

I started with a fresh stock 22r setup and swapped a 20r head and an adjustable timing gear this winter when my cheap aftermarket head gasket let go.  Cam is a stock 22r/re profile.  Fiddling with the cam timing did make noticeable changes in the seat of the pants driving experience.  I highly recommend an adjustable cam gear.

There is a lot of living in that thread.  You will see the more recent engine changes in the post from about January 17 on.

CFM formula is just the standard one floating around on line and on carb websites.  Not sure it it's correct, the 20r carb experiment I did would suggest otherwise .

Thanks!  I'll take a read through your thread soon.  Super busy with work and trying to get both my trucks roadworthy by the weekend.

[helipilot77]

I saw in the latest issue of 4WD Toyota Owner that low range off-road now offers a reproduction aisin carburetor. So no need to dig through wrecking yards to try to find a salvageable unit. I actually enjoy digging through wrecking yards though.

http://www.lowrangeoffroad.com/toyota-22r-new-reproduction-replacement-carburetor.html

[H8PVMNT [OP]]

That's a really good deal too.

[fasterspider]

I saw in the latest issue of 4WD Toyota Owner that low range off-road now offers a reproduction aisin carburetor. So no need to dig through wrecking yards to try to find a salvageable unit. I actually enjoy digging through wrecking yards though.

http://www.lowrangeoffroad.com/toyota-22r-new-reproduction-replacement-carburetor.html

Geeze, I wish this was known to me two years ago when I needed a carb. 😯
The price tag of $184.00 is only $34.00 more than I paid for a rebuilt used carb.

[redneckcustoms13]

Raman from the parts house is less than $200. I enjoy building my own though.

[fireitup]

I saw in the latest issue of 4WD Toyota Owner that low range off-road now offers a reproduction aisin carburetor. So no need to dig through wrecking yards to try to find a salvageable unit. I actually enjoy digging through wrecking yards though.

http://www.lowrangeoffroad.com/toyota-22r-new-reproduction-replacement-carburetor.html

FYI I went ahead and bought one of these to assist in my ongoing carb woes.  Going to start a writeup about it as it is (intentionally) missing some of the EGR additions to the carb.  Came with a "For Off Road Use Only" warning.  Not a big issue for me here as all emissions inspections are strictly visual, and most of the folks don't really care.

Probably would be an issue for those in Cali or anywhere that does a tailpipe test if going onto a street rig.

Also, hey everyone it's been a while!!

[helipilot77]

Cool. It will be good to hear how driveability is with it.

[L5wolvesf]

H8PVMNT

I found this post while looking into how the HAC operates and if it could be useful when converting to a Weber. Your Aisan study and info has been very interesting. My thought is the HAC is a useful item in spite of being part of the dreaded emissions system. What it does makes the vehicle run more efficiently by adjusting for environmental conditions on the fly - a real good thing IMO.

I won't be converting my '84 Toyota Pickup (22R, 2x, 4sp) to a Weber so the Aisan carb info should be useful if I decide to get into the carb. I wouldn't mind a bit more power, but the MPG sacrifice wouldn't thrill me - I currently get around 22 MPG. I drive it fairly easy since it is my DD.

I haven't read every word yet but I was wondering where you stand on the HAC after your experimentation.

[H8PVMNT [OP]]

The HAC is worth while on the Aisan in stock trim for sure.  I wouldn't bother trying it on a Weber since they lack the extra ports to make use of it, plus, it's pretty quick to just swap a jet in a Weber if you have a huge change in elevation.