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Dialing in LH2.4 on the General Leif and dyno tuning basics?

Finally did some actual tuning on the car! Got a few hours of driving in today with the computer connected, and the VE table is now close enough.

Conclusions:
  • This cam is big.
  • I need a bigger throttle body. By 5800 I've lost 3-5 kPa of manifold pressure (maybe more - I forgot to start data logging :-( )
  • Did I mention this cam is big? It starts to pull around 4500, and the shape of the VE table suggests peak torque is somewhere between 5k and 6k. This might change slightly with a larger throttle.
  • I need to swap in my t5, because the 2-3 gap is way too wide on an M47 now.

Track day tomorrow at Pacific!
 
I would love one of the 59mm throttle bodies from Timos Motor but they seem unwilling to help a brother out...trying to see if I can find a source for just throttle blades, I'll do my own oversize. Maybe if we had a bunch of people that wanted to do this, it would be worth their while.
 
shoestring said:
More is always better!!

Isn't it?
Click to expand...

It is! However, bigger can mean controllability problems at the bottom end where a small change in angle causes a very large change in area, which makes it hard to putter around (but will make power at the top). I'll eventually (maybe this moves it up the priority list) mill an adapter so I can switch to a Ford electronic throttle body that's ~75mm. Since it's electronic, you can keep really fine movements down at the closed-end so it doesn't hurt drivability (and also do other magic like automatic rev matching...).

I now have data from running the car on track, so I have a log with lots and lots of 3-6.5k RPM pulls.

Here's something pretty awesome:
9nu4k8w.jpg

Y axis is MAP, and X axis is RPM. Color is VE, but you can mostly ignore that for now. The whacky dip-then-bump in the 4800-5200 range indicates that the cam really loves 4800 rpm, then doesn't like 5200 as much, then starts to like things again back above 5600. However, since it's losing a full 7kpa between the peak at 3500 RPM down to the trough at 4800, the throttle needs to be bigger.

And the shape of peak VE agrees:

XAQMrkV.jpg


This suggests the sweet spot is around 4200-5000 on this cam, which feels about right driving it.

The resonance in the intake manifold is certainly a contributor here - that peak in VE is too flat to be from a well-matched cam and intake (which is a feature - it flattens out the torque peak).

tl;dr I (probably) need an intake that isn't the LH2.4 intake, and I need a bigger throttle.
 
shoestring said:
More is always better!!

Isn't it?
Click to expand...

Sorry dude, I was just messing with Cam here. The Timos throttle body upsizes are from the stock 55mm to 59mm, which ends up being something like an 11% increase in area.

75mm is frikkin huge, but being that you're looking at going electronic you're probably smarter than I and can make it work.

I am enjoying the science above. Testing+data+documentation>butt dyno.
 
Yay!
mck1117 said:
need to swap in my t5, because the 2-3 gap is way too wide on an M47 now!
Click to expand...
Get shorter tires and run a 4.10/4.30/4.56 rear end so you can use 3-5th gear and it?ll be much better. The spread with those gears is ok. Or get the T5 in there If you have one with the 2.95 1st gearset.

mck1117 said:
It is! However, bigger can mean controllability problems at the bottom end where a small change in angle causes a very large change in area, which makes it hard to putter around (but will make power at the top).
[...]
tl;dr I (probably) need an intake that isn't the LH2.4 intake, and I need a bigger throttle.
Click to expand...
850 NA throttle body solves that low throttle opening problem for us, it?s fine now! But yes, curious how a better intake works out for you and would like to see what you come up with on a dyno at some point. An intake and exhaust with proper dimensions for your target rpm range and camshaft should probably be done before you bother dyno tuning, if you think you?ll do them any time soon?

Those graphs and logs are definitely the benefit of running programmable EFI unlike shoestring/redblockpowered and I here...
 
Oh, by the way, I turned Lambda feedback on for our race at PIR because the car was running too rich in the lighter load areas(13:1) and I wanted to try and make sure we had no fuel capacity issues again. Because of that, it ended up learning and leaning out the WOT stuff a little more than wanted but I sort of expected it(I could adjust the tables to keep it from happening above a certain load and/or rpm, but didn't). It was between 13.2-13.8:1 with it mostly being around 13.5:1 during the race. I want a little more fat than that to keep the engine cooler, but I don’t know if that had anything to do with why we were having some warmer engine temperatures. I don’t think the radiator leak was helping.... hah
 
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Yea I've always found that once you get the map the way you want it, if you turn on lambda feedback, LH will lean it out. I guess you just have to go richer than you want up top to log the result down to where you want it once it's leaned out?
 
klr142 said:
run a 4.10/4.30/4.56 rear end so you can use 3-5th gear and it?ll be much better
Click to expand...

For some reason I thought I had a 3.54 (which isn't great anyway), but I looked it up and my car should actually have a 3.31 (though it has no sticker on it, so who knows). I think my real problem is that my axle is a 3.31. I do have a legit Volvo 4.11 gearset from a 1041, which I think will swap in to my 1031 housing if I use the 1041 yoke.

Out of curiosity, why do you recommend using 3-5 instead of 2-4? With a 4.11, the T5 I have (3.35 1st, 0.68 5th) should put 2-3-4 in a pretty nice spot (61-91-121 mph respectively at 6500 rpm).

klr142 said:
An intake and exhaust with proper dimensions for your target rpm range and camshaft should probably be done before you bother dyno tuning, if you think you?ll do them any time soon?
Click to expand...

Agree - probably not worth putting it on a dyno until I have an intake sorted out. The exhaust is already sorted, it's a KL 4-2-1 header to 2.5". We'll see if intake gets done before October. There's a good chance, as there isn't too much else left to do on the car.
 
klr142 said:
Oh, by the way, I turned Lambda feedback on for our race at PIR because the car was running too rich in the lighter load areas(13:1) and I wanted to try and make sure we had no fuel capacity issues again. Because of that, it ended up learning and leaning out the WOT stuff a little more than wanted but I sort of expected it. It was between 13.2-13.8:1 with it mostly being around 13.5:1 during the race. I want a little more fat than that to keep the engine cooler, but I don?t know if that had anything to do with why we were having some warmer engine temperatures. I don?t think the radiator leak was helping.... hah
Click to expand...

I tried to be smart and disable logging channels I didn't need - but accidentally disabled logging AFR in the process. However I was running auto tune the first two sessions, so it got the fueling pretty well dialed in while I was driving. From looking at the gauge, AFRs across the top row were dead flat 13-13.2 all the way across, leaning out as you dropped off load. Car sat dead on 81-82 degrees the whole time (mechanical fan, stock 240 radiator). Though it was in the rain, so take it with a grain of salt.
 
muppetman342 said:
Yea I've always found that once you get the map the way you want it, if you turn on lambda feedback, LH will lean it out. I guess you just have to go richer than you want up top to log the result down to where you want it once it's leaned out?
Click to expand...
Yes, but the learning and leaning is reduced if you have the tune lean enough to begin with that it doesn't need to adapt and lean out further. To some extent, anyway...

EDIT: I think a lot of it is that the higher load/low rpm stuff needs to be leaner than I have it on my main fuel map, and the low load high rpm stuff also needs to be leaner. If I can get those to pretty much stoich/14.7:1, it won't learn as much. I should also tinker with having the oxygen sensor feedback/closed loop operation limited to under a certain load and rpm to finalize it further. So far, just having it off or on has been fine with more tuning, too.

mck1117 said:
Out of curiosity, why do you recommend using 3-5 instead of 2-4? With a 4.11, the T5 I have (3.35 1st, 0.68 5th) should put 2-3-4 in a pretty nice spot (61-91-121 mph respectively at 6500 rpm).

That was in regards to using an M47 transmission, but with your T5, I would set it up for 2nd-4th gear as you suggest.

Agree - probably not worth putting it on a dyno until I have an intake sorted out. The exhaust is already sorted, it's a KL 4-2-1 header to 2.5". We'll see if intake gets done before October. There's a good chance, as there isn't too much else left to do on the car.
Click to expand...
See the red with the first part, but can you tell me the tube diameters on your header?

mck1117 said:
I tried to be smart and disable logging channels I didn't need - but accidentally disabled logging AFR in the process. However I was running auto tune the first two sessions, so it got the fueling pretty well dialed in while I was driving. From looking at the gauge, AFRs across the top row were dead flat 13-13.2 all the way across, leaning out as you dropped off load. Car sat dead on 81-82 degrees the whole time (mechanical fan, stock 240 radiator). Though it was in the rain, so take it with a grain of salt.
Click to expand...
Oops! What temp. thermostat do you have in there? I'd go up to the 87/88? one if you have the 82? for slightly better efficiency. We also have an 82? in the General Leif but I want to swap it out as it was dipping near warm-up enrichment territory and we aren't detonation limited which was one of the reasons for going slightly cooler.
 
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Bump! I fixed the broken link with the dyno run picture.

I also wanted to BUMP this because we have the head off and I see now that it's basically a stock 405 head with some exhaust valve throat area. The ports, when viewed from the manifold mounting surfaces, look stock. So, this is basically a B230 with a shaved 405 head, unshrouded exhaust side of the chamber, larger camshaft, b21F intake manifold with a relocated larger throttle body, custom exhaust and some tuning. Pretty basic stuff!

Also, mck1117, you never mentioned what size your header was. There are some that are so small that they're only good for a basically stock engine.

And some more also... Our current downpipe off the stock(slightly ported) stock exhaust manifold is made of 44.5mm(1.75") OD piping that is approximately 650mm long before the 2-1 merge into a 2.5" exhaust system. Speaking with Erland Cox, he suggested going up to 51mm(2") OD piping on the downpipe with 650-700mm long runners. Then having the first muffler around 400mm behind the merge, or 800mm behind the merge. If running more mufflers, the next one could be 1600mm or 3200mm behind the merge.

I am going to have the head flowed soon to see what it does and compare it to my big valved 530 head for NLMGG that has some port work. I'm curious to see how they compare as the engine seemed stronger with the more "stock" 405 head on it. It did have higher compression with the 405 head, but I can't imagine that was the reason for all of it.

We will also be putting our camshaft that is similar in size to an ENEM C2 camshaft in the car for this season(105LSA is not ideal for the setup, but it'll run). I spoke to various europeans about camshaft selection for use with stock/near stock base circles and Enem suggested their K14 which is a step up in duration compared to the K15 and C2 which are a step up in duration from the K13, but still with 12.5mm of lift and a stock base circle. AGAP recommended their R33-254-13 cam as being the largest stock base circle came and to use with a relatively high 110LSA to help with the close to stock manifolds and LH2.4. Erland Cox's first suggestion was the ENEM C2 as being great bang for the stock buckets.

Ps. We ran the stock redblock thermostat temp of 87/88? in October at PIR with no issues. Engine ran great the whole time and we came in 2nd place in class on one day and had multiple issues with the throttle spool on the second day. Both days we should have one in class but that's racing. Our strongest B class competitors were having issues or not participating that weekend, so we can't stop improving. The bar keeps going higher, anyway!
 
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klr142 said:
Bump! I fixed the broken link with the dyno run picture.

Also, mck1117, you never mentioned what size your header was. There are some that are so small that they're only good for a basically stock engine.

And some more also... Our current downpipe off the stock(slightly ported) stock exhaust manifold is made of 44.5mm(1.75") OD piping that is approximately 650mm long before the 2-1 merge into a 2.5" exhaust system. Speaking with Erland Cox, he suggested going up to 51mm(2") OD piping on the downpipe with 650-700mm long runners. Then having the first muffler around 400mm behind the merge, or 800mm behind the merge. If running more mufflers, the next one could be 1600mm or 3200mm behind the merge.
Click to expand...

It's this header: https://shop.klracing.se/sv/artiklar/extraktoirgrenror-volvo-240-8v-4-2-1.html. 42mm primaries, 48mm secondary, 2.5" outlet.

You interested in it? We've switched to a (low boost) rotary muffler, so I'd be happy to sell it to The General.
 
No thanks, that's barely larger than stock and we don't really have room for anything. No more high compression and big camshaft build anymore, aye?
 
klr142 said:
No thanks, that's barely larger than stock and we don't really have room for anything.
Click to expand...

Oh right, I forgot the 142 has zero lateral space for a header to exist in. I think this header would be inside your frame rail.
 
redblockpowered said:
You have the 2-1 downpipe choke point thing cut out, right? That made a difference for us.
Click to expand...
We have a custom downpipe attached to a slightly cleaned up factory cast manifold. Erland is suggesting we build a new one out of 2" pipe for 2" secondaries(47-48mm ID, 50-51mm OD). It's actually not a bad setup, as can be seen by us running a near stock head with high compression, a camshaft and B21F intake manifold with a tune to get 150+whp.

mck1117 said:
Oh right, I forgot the 142 has zero lateral space for a header to exist in. I think this header would be inside your frame rail.
Click to expand...
Correct!
 
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