Holley Avenger EFI on Budget 532 lbs-ft 383

[user-612937456]

David I have been following this thread word for word sitting on the edge of my seat lol I've got upcoming project that this will fit precisely Especially the 87octane part. can you share the details of the components or does one of your books in particular have this specific recipe in it?

[David Vizard]

David I have been following this thread word for word sitting on the edge of my seat lol I've got upcoming project that this will fit precisely Especially the 87octane part. Can you share the details of the components or does one of your books in particular have this specific recipe in it?

Sure - but rather than spend Lord knows how long typing it up PM me with your phone # and a time to call and I will spill the beans.
DV

[ap72]

David I have been following this thread word for word sitting on the edge of my seat lol I've got upcoming project that this will fit precisely Especially the 87octane part. Can you share the details of the components or does one of your books in particular have this specific recipe in it?

Sure - but rather than spend Lord knows how long typing it up PM me with your phone # and a time to call and I will spill the beans.
DV

Quick question on your cam choice- how many street miles do you think the valve train would hold up? Does the old "keep it under .500" lift" rule still apply if you want 100,000 miles out of it? I know roller cam and spring tech has come a long way but what about rocker wear and valve guides?

[wyrmrider]

just a comment on the 100,000 mile street comment and over .5 lift
you want to avoid cutting down the guides so you have to think through the longer valve and change of valve tip to rocker arm length drill then get the right springs
better quality valves 3/8 ex stems etc are also considerations-
it can be done
just IMHO here
geometry has to be right to go anywhere near that long

[David Vizard]

David I have been following this thread word for word sitting on the edge of my seat lol I've got upcoming project that this will fit precisely Especially the 87octane part. Can you share the details of the components or does one of your books in particular have this specific recipe in it?

Sure - but rather than spend Lord knows how long typing it up PM me with your phone # and a time to call and I will spill the beans.
DV

Quick question on your cam choice- how many street miles do you think the valve train would hold up? Does the old "keep it under .500" lift" rule still apply if you want 100,000 miles out of it? I know roller cam and spring tech has come a long way but what about rocker wear and valve guides?

Pick a good set of profiles and set it up with a top quality spring having a high resonant frequency to deliver the minimum spring forces consistent with the rpm and use a good engine oil and this setup with 50 or so 1/4 mile passes a year should go 75,000 miles.

[PackardV8]

For those who've actually done it, what's the bottom line cost these days, going from carb and mechanical pump to the Holley EFI?

(Some of you will not be surprised, a guy came in complaining about his EFI conversion requiring a return line, a new high pressure fuel pump, a wideband O2 sensor, etc. "Jeez, the ad in the magazine made out it was easy, like swappin' carbs; and it is supposed to tune itself." And no, it doesn't, because he's still not figured out that suggested method of getting it to idle with the too-big cam.)

what I normally do with anything that has much overlap where it is obviously rich when the lambda says otherwise is shut learning off a few hundred RPM above idle & manually tune the AFR below that. Just grab about 9 points around your idle & lean them til the RPM drops like you would do with a carb difference being instead of a screwdriver.. while kicked back in your easy chair........ you use the up/down keys. Reason is with much overlap the O2 sensor will read lean when it isn't & keep adding fuel. Can also happen with the sensor too close to the exhaust opening

[NewbVetteGuy]

David,

Is this build documented in detail anywhere? -I'm happy to buy another book; I've got your "Building High-Performance SBCs on a Budget" book, but I think the newest release is 2009 or 2012 and this build isn't in there... Is this build documented in some other published book? Sitting on a Publisher's desk waiting for a publication date? Lost forever in a desk drawer somewhere?


532 ft lbs @ 4,800 is a number I didn't think I'd see on an NA 383 SBC, especially with an HP peak of 5,800 RPM and definitely not without a long runner intake.

I have a slightly less aggressive hydraulic roller cam with the same goals as this build and a 110 LSA vs. the 128 rule's 106.5 LSA so I'm super interested to dive into the details and see what difference the more aggressive ramp and LSA made. Note: I need the extra vacuum and like the wider curve of the 110 LSA and have a great cam so I'm not going to change it, but I do want to understand what makes this beast tick and what the differences are.

-What rings are you running with this build? Vacuum pump or no vacuum pump? (I'd imagine not given the 5,800 max RPM but the torque # at that RPM has me questioning everything.)

Given that this was already running a Holley EFI, do you feel that you could've got even another 5 ft lbs by using a 60-2 /58x crank trigger and LS ignition coil for immaculately accurate ignition timing? (Because that last 5 ft lbs would put this build over 1.4 ft lbs / cube; those last 5 ft lbs would've driven me nuts; I'd think if you could decrease the dyno room's air temps by a few degrees you could've hit 1.4 ft lbs / cube.)


Adam

[Scotthatch]

.Cam was a Comp single pattern Hyd QXI roller series 285/233 delivering a measured 0.630 lift with high ratio Scorpion rockers. Incidentally my 128 LCA formula, when applied to this engine, came out at 106.7 degrees and the cam, computed on COS-Cam, was ground on a 107 LCA. Note the big torque/cube numbers and the fact that at peak torque it closely approached the 1.4 mark and this was all done with very basic parts. So once again for the record if you don’t like/agree with the 128 formula for a SBC don’t use it. BTW the cam was power timed in. Cannot remember where it ended up for best output.


I think you already missed what he did

[Scotthatch]

If we look at what we do know you will see he says 260 cfm Max. We don't know if that is Max for the head or at Max lift but we can use that number to see where it goes ..

The engine made 542 HP and that comes out to 263.5 cfm so to make use of the 260 cfm we need 101.4 port efficiency or a closing point on the intake valve of at least 57 degrees ... the closing point straight up is 69.5 degrees but he also states that he fussed with how it was installed so maybe +4? That would put it at 65.5 degrees ... if the intake flow was a little low or flow at peak lift a little lower then 260 the few extra degrees would make sense for peak HP ...

If you look the intake opens early this exposes more valve at peak piston velocity and allows more air to fill the cylinder at lower rpm ... this is your torque .... the problem with running a big enough cam to do this is that the overlap damages power at low speed by contamination of the charge ... to stop that the cam is a lot smaller on the exhaust side ....

Drawing below is this cam ....green circle numbers are +4

15270173735590.jpg

[NewbVetteGuy]

.Cam was a Comp single pattern Hyd QXI roller series 285/233 delivering a measured 0.630 lift with high ratio Scorpion rockers. Incidentally my 128 LCA formula, when applied to this engine, came out at 106.7 degrees and the cam, computed on COS-Cam, was ground on a 107 LCA. Note the big torque/cube numbers and the fact that at peak torque it closely approached the 1.4 mark and this was all done with very basic parts. So once again for the record if you don’t like/agree with the 128 formula for a SBC don’t use it. BTW the cam was power timed in. Cannot remember where it ended up for best output.


I think you already missed what he did

Nope; read all that. I'm interested in the details that WEREN'T in that paragraph. There's got to be more to it to get those numbers, right?
-I'm sure we could track down which Chinese casting @ 200cc has a 260CFM flow, but were there any other tricks to this like a super thin ring pack?

You can't get those results just bolting those parts together and quickly porting the exhaust ports of those Chinese heads or we would've seen something close to these numbers already, right?


Adam

[Scotthatch]

It's all in the camshaft I'm sure ... look at it when was the last time you saw a dyno run with a cam like that ??

About the only other thing knowing him is what temperature was it at and what fuel

As for the heads I have not worked on any of Chinese heads yet but I would guess they are a copy of another 23 degree head ... not a lot of mystery left in 23 degree heads anymore

[NewbVetteGuy]

It's all in the camshaft I'm sure ... look at it when was the last time you saw a dyno run with a cam like that ??

About the only other thing knowing him is what temperature was it at and what fuel

As for the heads I have not worked on any of Chinese heads yet but I would guess they are a copy of another 23 degree head ... not a lot of mystery left in 23 degree heads anymore

Right but AFR 195cc heads and the Profiler 195cc heads have another 20 more CFM at a lower min CSA than a 200cc 23deg head and should have higher velocity through the ports and see at least these results, then but we don't see it. There are TONS of AFR 195cc 383s with Performer Air Gaps -do you really think anyone slapping one of these Comp Cams QXI 285/233 cams in one with a 107 LCA is going to see these results?!? I still find these numbers hard to believe without some other tricks; there would be more examples out there if the only key was the cam.

The parts are common; the collection of parts probably isn't too uncommon; the results are quite uncommon. Why?

For the max torque under 6,000 RPM SBC 383 geeks the results of this build is the 23 degree street motor holy grail as far as I'm concerned. A street BEAST with off-the-shelf parts; now what are all the little things that have to be replicated to replicate the results? A fair question that I'm happy to pay to get the answer to, but this build is too great to keep a secret.


Adam

[MadBill]

If we look at what we do know you will see he says 260 cfm Max. We don't know if that is Max for the head or at Max lift but we can use that number to see where it goes ..

The engine made 542 HP and that comes out to 263.5 cfm so to make use of the 260 cfm we need 101.4 port efficiency or a closing point on the intake valve of at least 57 degrees ... the closing point straight up is 69.5 degrees but he also states that he fussed with how it was installed so maybe +4? That would put it at 65.5 degrees ... if the intake flow was a little low or flow at peak lift a little lower then 260 the few extra degrees would make sense for peak HP ...

If you look the intake opens early this exposes more valve at peak piston velocity and allows more air to fill the cylinder at lower rpm ... this is your torque .... the problem with running a big enough cam to do this is that the overlap damages power at low speed by contamination of the charge ... to stop that the cam is a lot smaller on the exhaust side ....

Drawing below is this cam ....green circle numbers are +4 15270173735590.jpg

Scotthatch, unless I'm reading it wrong, your chart seems to show (and later posts assume) the cam as having 285° intake & 233°exhaust duration . David's original post stated it's a single pattern with 285° advertised, 233° @ 0.050...

[Scotthatch]

If we look at what we do know you will see he says 260 cfm Max. We don't know if that is Max for the head or at Max lift but we can use that number to see where it goes ..

The engine made 542 HP and that comes out to 263.5 cfm so to make use of the 260 cfm we need 101.4 port efficiency or a closing point on the intake valve of at least 57 degrees ... the closing point straight up is 69.5 degrees but he also states that he fussed with how it was installed so maybe +4? That would put it at 65.5 degrees ... if the intake flow was a little low or flow at peak lift a little lower then 260 the few extra degrees would make sense for peak HP ...

If you look the intake opens early this exposes more valve at peak piston velocity and allows more air to fill the cylinder at lower rpm ... this is your torque .... the problem with running a big enough cam to do this is that the overlap damages power at low speed by contamination of the charge ... to stop that the cam is a lot smaller on the exhaust side ....

Drawing below is this cam ....green circle numbers are +4 15270173735590.jpg

Scotthatch, unless I'm reading it wrong, your chart seems to show (and later posts assume) the cam as having 285° intake & 233°exhaust duration . David's original post stated it's a single pattern with 285° advertised, 233° @ 0.050...

My bad .... you are right .... that's what I get for reading too fast

[NewbVetteGuy]

My best guess is that this build used the Promaxx 200cc heads; they advertise 280 CFM @ 0.600" but a few reputable places have ended up with 260 CFM on a 4.060" bore when flowing them themselves. [Edit] Nope, I'm way wrong; the ProMax 200cc heads have way better exhaust ports than 160CFM...

The AFR 195cc heads flow 280 CFM @ 0.500" and for a worst-case let's assume that the flow doesn't increase up at the max valve lift with this cam; the min CSA on the AFR 195cc heads is only 1.905".

The Profiler 195cc heads flow 274 CFM @ 0.600" so again worst-case let's assume no flow increase at max valve lift with this cam -the min CSA is 2.15" on the 195cc Profiler heads.

The Promaxx 200s have 260 CFM @ 0.550" and again worst-case let's say no flow increase further at max valve lift; I have no idea what the min CSA is on the Promaxx 200s; can't find it anywhere to save my life.



We could easily do the FPS calculation for the AFR and Profiler heads and then if by some miracle the Promaxx flowed it's 260 CFM on the same Min CSA as the AFRs, it being down 20 CFM at the same min CSA it would still be down on average and max torque- the max torque and average torque only gets worse if the Min CSA is closer to or even larger than the Profilers.


This build should gain further ft lbs with AFR 195cc heads and the same cam and bottom-end for sure...

I'd love to see someone already doing a 383 build with AFR 195cc heads and an Air Gap just swap whatever cam they were going to use for this same QXI and do a before and after- you'd need an AFR head with the 8605 spring upgrade, but I think it would be super educational and a great real-life test of the 128 rule... And a monsterous peak torque # for bragging rights even if it doesn't hit 532 ft lbs.

I just can't get enough of builds like this... BigBlock-like torque out of a lowly 383.


Adam