Dyno Testing Promaxx LS3 Small Bore Heads
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- เผยแพร่เมื่อ 9 ก.พ. 2025
- I show the dyno test results of the promaxx small bore ls3 heads. I also give flow numbers and other info on the heads.
Link to purchase dyno results being tested.
weingartnerrac...
Link to preorder book
weingartnerrac...
Some people have nothing to do but question & argue, and this seems to me to be the biggest dowfall of turning the comments on. I can not imagine the time you spend managing your channel, let alone the dyno testing & your full-time job. You earn every penny you make. I appreciate you doing this & sharing the information.
Dude, it's the comment section, people are allowed to express their opinions, you actively have to click on the section to read the comments.
So if you don't like comments, just watch the video and don't read through them.
I actively will avoid channels that disable comments.
Wow. This will be my second set of pro max heads. They really bring an engine to life.
Eric, I still can't believe you're actually testing stuff, and we have armchair mechanics arguing with you. I love these videos
Appreciate the data and tests. With 2 points compression increase and 20 cfm I thought also 700 would be doable. I guess no matter how much we dream about it at night and keep theorizing it's ability to reacha goal, we will never know unless we dyno it.
I really think where the "LS is Superior " argument originates is in Stock form. Average LS power numbers versus a 70's or 80's era factory smallblock will show a vast power improvement. When both units utilize the best aftermarket parts available, the playing field definitely balances better.
Well said
What the small block lacks in head flow potential it makes up with less oil pumping losses unless you use dry sump oiling.
@@sebbonxxsebbon6824 There is no Universe where oli pumping losses will eclipse a 30-40+ cfm increase in head flow.
@@sebbonxxsebbon6824lmao that's ridiculous
I love cars bikes snowmobiles well almost anything that has HP lol!!
Iv been doing small engine work since i was 11 im now 45. Ported my first engine at age 14 2 stroke 488 fugie. Anyway made great power with twin pipes milled heads it was stellar. But it finally blew ring caught exhaust port. I didn’t taper port enough live u learn. Iv had camaros since i was 16 some were hot rods other ones some bolt ons. Im new to car engine building iv learned a lot just from watching a few of ur head porting videos.
Heard so much BS from people threw the years it’s hard to believe anyone or anything.
But with guys like u that actually have the shop the tools to prove what u do or say i trust.
Great stuff thanks for sharing
Great test, it’s great to see real world results, not Magazine Dyno numbers made to placate to advertisers
Love your real world vidio and dyno numbers. I believe the horsepower gain came from the 2 points in compression and if you can live with 13 to 1 they're great heads cant wait to see the bigger camshaft numbers
Great recommendation, specially if there are different parts on an engine when they try to compare things to another that is different.
Really appreciate what you do Eric
Im still going back to this is more crank stroke than a factory setup.
But I guess that factory cid combinations have been beat to death.
I am happy to finally see there is no magic cam change with stock heads and 5.3 or 6.0 that makes 700 hp.
And you are still not getting there without aftermarket heads and 4.00 stroke aftermarket crank for sure.
The LS engines are good. The dyno secessions are great.
Still some really great power.
Im going to go back and watch all of them again.
And then I’m going to go back and watch all the sbc videos with my books out and make notes.
Happy dynos are here again FDR - all over the internet My old flow bench had a tilted tube manometer and my dyno read torque on a big analog scale. Actual numbers? no but we could see trends NO SWEEPS
It seems that with that tall a manifold you could run a tunnel ram might help with those spread intake ports
Does look like an E 85 build, Change the ex seats I like Dura Bond sintered for my HD builds but I retired before much lS
do you check rocker geometry with higher than stock lift cam> lash caps and shorter pushrods might be a fix with those fixed fulcrum heights Are pushrods holes large enough for large pushrods or enough meat to open up? Nice work Eric
Incredible that LS engines make so much power with little duration @.050 on the camshaft.
That’s exactly what I said, 678 hp is darn good for that cam, if he went with the same duration cam but with a solid roller grind, he would probably be over 700,
I agree
It would make less the same duration on a hydraulic roller is several degrees smaller on a solid roller with lash.
@@WeingartnerRacing I should have been clearer and said same actual* duration not advertised, however I still wouldn’t be surprised if made more simply because of the valve action you can get with a solid roller, the valves should open quicker than what you can with a hydraulic roller, thanks for the response, I actually watched the video twice today! I tell everyone I know that’s into this stuff to watch your channel
@drivinwithdrew7676
the speed a valve opens or closes is a function of lobe design, not weather it has a hyd or solid lifter.
Thanks for testing . Really impressive work
Eric, it would be cool if you did a dyno test of the Titan oil billet oil pump versus the moroso shark tooth billet oil pump versus a conventional spur gear pump. Very interested to see the results from that.
I did one between spurr gear and titan.
I remember, but you did it with both the Titan oil pump and a new oil pan so, can't say where the 30 horsepower came from I would assume most of it came from the pan.. maybe emailing or moroso donate one to the cause for a future tests.
I think I will be using these heads for my LS build.
Stage two cam, LSXR intake and these heads on a 38X stroker should be plenty.
That's awesome HP out of that cam. Would be awesome in a street car and drag race it.
It is my understanding that you can bore the 5.3 iron block to 3.905, which is an LS1 over bore size. They even have shelf pistons for that size.
Hope you can test the 2 piece lS3 intake that Charles Servedio just got done with. He did a great job! The numbers and the even runner flows look very good. Thanks for the videos.
Before the internet it was magazine articles, whatever Hot Rod. Car Craft, or Popular Hot Rodding said was gospel truth. I worked at a machine shop in the 80's, it was constant, I suspect it always will be.
Eric plz read. Long time sub. In a vid you did a while back about the swirl in a head reversing after a certain lift point, Darrin morgan talks about it in his video part 2 of 3 around 27 minutes in. You have mentioned before that you have talked to darin before for insight. One of his key talking points, especially about square port LS heads, which you have been testing recently, is pressure recovery at the valve in the chamber. especially how detrimental laying back the short radius is to low rpm power. I think a video showing pressure recovery with the head flipped over and showing air speed around the valve would be great insight to your cylinder head videos. Its something I havent seen you talk about and it would show intake reversion problems with every cylinder head you flow. Darin is the only person i have seen talk about this, and I feel like it is a crucial figure that should be observed regarding cylinder head flow.
also, please stop responding to internet trolls in your videos. It will be hard, but noone cares what they say. They have no proof to their "claims" and I promise 99.99% of your viewers do not read the comments. They feed off of your replying to them. If you want to address trolls, do it at the end of the video, and only if you feel like it is a comment that absolutely warrents a reply.
I also want to thank you for a video you did years back, about not flowing exhaust ports with a pipe and the effect that different pipe sizes and TURNS they make effect the results. It was illuminating to say the least. TY for all you do.
your data aquisition is top tier. id sugest using excel as way to do comps. it would show u some data u r missing.
Sweet video as usual man, I think it peaking earlier with those heads, may be telling you it’s out of cam, in my opinion that’s bigggg power for a cam that little and no direct injection,
I might buy the data off you, if it has all the port numbers it would be good to model it in engine analyser pro, so I can play around with cams a bit.
I'm leaning towards this head for a 5.7 build.
My mate has a commodore that caught fire after a burn out, it's a tired old leaky 5.7 ready for a rebuild.
641hp seems REALLY good for a 408 with that cam. Of course it’s more compression and more octane than what I’m comparing it to.
Could that little longer runner length be the reason the promaxx peaked sooner than enforcer?
In the end, Ls and small block fans are arguing over who’s 2nd best. Big Block is King.
Stock vs stock, the LS is better. Stock being key word. Throw cash and tuning in, it becomes a personal taste argument (chest or butt fan)
Except Ford guys, they’re the feet weirdos
I just got done reading a comment on a fbody board. Guy was asking about putting a big block in a 4th gen fbody. Bet there was 20 plus guys that said to just ls swap it it make more power cheaper than that boat anchor. Lmao the ls fan boy crowd just don't know.
@@michaelstoker6710 you can make as much horsepower. I am with my build. You can do it with a small block too. But people forget the almighty torque number. Build for build, you can’t beat the big blocks torque. I went with a Ls just because it’s my daily and I can’t afford to feed the beast. 😂😢 real world problems. Pay to play
Thanks for the video.
Yeah I saw that you tuber Knick that valve seat, looks like he already lapped the seats too. I didn’t say anything though, who knows he may have touched it up real quick with a stone or something without showing it. There’s all the stuff we don’t see you guys do.
I’d like to see it with a bigger cam but you don’t need a solid roller for big power in an LS. Go look at the LS hydraulic records
Maybe we can put solid rollers on a hydraulic cam and really knock it out of the park. 😂😂😂😂😂 Geeze
What size is the cam, I missed that
Years ago a group of acousticians tried to fix the spread of an error in the formula to calculate Helmholtz resonators caused by a misprint. They couldn’t keep up with the error proliferation. Their data showed a 9:1 ratio of bad to good. I changed it to 10:1. Things have to have gotten worse and since I just created a new FUD we’ll see which one wins. 😂
Motown LS Dyno build next please 😂
I was thinking the LS was a better platform for making power than the good ole SBC. If I am interpreting correctly this is proving difficult.
What kind of air filtration system do you use in your grind shop. Just wondering how you work with a full beard.
The test results will be ok for the big bore will be completely different to a small bore engine that they are made for. So not really a compatibility test that would show the small bore guys how they would work. Wouldn't it?
Im wondering how these would do on a lq9 with a ls3 intake and 92mm tb. Ive got the above mentioned with stock ls3 heads (supposedly 64 cc chamber but doubting it) and a 227 231 cam with 620 lift.
I know all dynos are diferent but the car only put down 391wheel, unknown tq through a 4l80 and 323 gears. Only traps 115 in the 1/4 and 92in the 1/8th.
Comb has been together for 7yrs though. Car is a little over 3700lbs with me in it.
Maybe a larger solid roller cam and a nice set of 2” headers would make 700
Maybe more intake duration and a little more lift would benefit to get close to 700hp I ran a custom tsp 233/250@113 on a high ram 6.0 in a 01 Silverado single cab and it kept up with built ls3 5th gen Camaros
I can feel you typing right now!! 😂😂
fwiw, the efficiency from compression is in every thermodynamics textbook. 1-R^(-0.4). Going from 11.1 to 13.1 compression is 4% power, if all else is equal.
If all is equal
@@WeingartnerRacing The compression IS 4% - anything else you do may add or subtract to that. It's good to know that you gained power, it's better to know WHY you gained power, or why you lost power.
@@chrisstavro4698if it only worked like the text book claims because it rarely does. When you gain or lose compression how did you do it? Did it reduce quench, make flame travel worse? I can go on and on. This is why formulas aren’t absolutes.
In the lower compression ratios like going from 8.0 to 9.0 you can gain 4-5 percent power. It’s like everything else in that diminishing returns takes place the higher you go.
@WeingartnerRacing do you know the cranking compression psi or the dynamic compression on this?
I know you ran 110 but I'm curious if 93 would suffice based on dynamic/cranking?
What would you consider the psi/dynamic limits of pump gas, or is that just a DV thing?
Thanks
I didn’t check.
@WeingartnerRacing if you have time next time, will you?
I think it'd also be a good segway into how cam timing affects compression. ie, the high compression engines back in the day that rolled off the line with high compression for the available pump gas and survived.
I'd like to see how advancing and retarding cam timing affects dynamic compression. Orrr, how to reduce a high static comp engine by choosing a specific cam to reduce comp to be able to run pump gas.
Thanks for all you do
Should have ran it out of the box as-is, with the leaking valves because that's how most people would buy and run them. Who in their right mind buys ready heads to redo a valve job and blend again. Sound like a QC issue at Promax
I couldn’t do that. My luck it would have fatigued the valve and broke it.
@@WeingartnerRacing understandable you want to fix poor QC. If you have pictures and/or videos how they were out of the box and publicize them in a manner 'what to watch for' and not a slam at the supplier.
I deal with similar things in the import world. I don't expect parts to be clean or 100% right out of the box, although it's nice when that happens, but I have dealt with huge, reputable suppliers offer oil pans with packing lint all over the oil pan and baffle. It's not a problem as I clean everything, but they Loctite the baffle bolts. What kind of a message does that send to the customer when the parts are dirty, but final-assembled. After pointing out the strange decision by the manufacturer, I was made to be the bad, crazy guy. I do 'right out of the box' posts to show what the customer will expect to see and what they need to address to avoid failures. I can't imagine how many of those oil pans full of packing paper lint and debris were slapped straight on the motor and called good.
Keep up the nice work. Dyno comparison is a great tool.
Dynos don't lie unless the correction factor is being intentionally messed with. I have seen that intentionally done on the Superflow to inflate the numbers to the customer via fudging the correction factor.
I have to say that this type of presentation is much better.
If these are a "mast" ripoff you can get a more affordable set of shaft rockers from yella terrra for it.
Yella Terra, good ol Aussie company, they make heads for our 202 and 308/304
I watched some “other” dyno testing. No one clarifies that water and oil temp are consistent.
It’s been said in magazines for years. Especially. When the emc challenge was going on
Can you dyno test a SBC 383? And take it from mild to wild?
I plan to.
Your numbers look really really good for what it is. What rpm rate is the dyno pull?
600
@WeingartnerRacing what did you achieve for ring resistance? You got something going on. These are stellar results
@@bowsertownesit’s not that stellar. Many engines are better.
@@WeingartnerRacing for 4.030 bore and what it is, it's a great little build.
Eric, will you develop a port for the afr 227 competition SBC head ?
Probably
Do your flow benches correct to for temp. and atmospheric pressure?
No on orfice bench you don’t have too.
Is this the video that started the Camshaft challenge?
The one after
Any chance on adding the liberty performance LS3 heads to your test???
No. The wouldn’t warranty a head with there seats breaking on because I blended there valve job. I’m not supporting them.
That ls3 had a point or two of compression over the 406 sbc right?
Yes two points on these heads.
@@WeingartnerRacing now I’m wondering how good the sbc would be with that much compression🤔I’m starting to think like you from all the testing that you’ve done, the LS platform isn’t as superior as popular belief says it is.
Eric does more flow always equal more power?
I'm not Eric. But, No.
No
@WeingartnerRacing
It'd be cool to see you ALL OUT port and VJ the LS3s, just to see what a bad ass set is capable of, IF you have the time of course.
@@WeingartnerRacing I’d be curious to see the big pro max heads vs the small bore. That’s why I asked about flow.
Why are you using such small headers? Can explain please?
Probably only ones he has I'd assume. But typically 1 7/8" does better in performance LS applications (not a parrot,lol)
I know there are many variables involved before an Absolute could be given on how much compression I can get away with on my project on pump gas, But I almost can't help from asking the question anyway. So i'm leaving this comment, just to Distract my fingers. 🥵
Bad info on the web proliferates at a 10:1 ratio to good info which ends up getting buried.
Lol at that 10:1 stat. Not sure but it is sure alot.
Ain’t nothing new or unique to the internet. Back in the -60’s, there was a saying, “bullsh*t / talkin’ sh*t, makes the world go around…”
@georgedreisch2662 that tshirt is interesting. The internet just made more people realize how common things are.
Great testing thanks
@weingartnerracing speaking of parroting, do/have you watched Richard Holdeners videos and all of the testing he's done?
Or, the engine masters video series? (I know you were a REAL competitor, lol) You probably don't have alot of time to sit and watch YT videos but, i wanted to hear your opinions on BOTH of them.
IMO, i feel like it's more realistic than a guy's opinion online or (magazine back in the day) trying to sell you something.
I feel like this is where alot of the parroting comes from.
I watched engine master and some of Richard’s stuff. Both are good but both of them are tests primarily done for magazine publishers. They have vested interest in seeing certain brands do well because of advertising. This isn’t a blanket statement because many are amazing tests.
Some people will only show the results they want, your showing all you have, thanks for sharing, all the best to you and your loved ones
What kinda valve job?0
45 degree
Mr. Weingarten,
isn't everything we do somewhat "pairing"? Everything from old history 2 things n the Bible r paired. Science and math can b paired but we can prove both with our own experiments. I think we r brainwashed 2 believe what others say instead of doing what u did and finding out ourselves.
I wish we had the equipment and raw info they use to speculate on climate change and other scientific theories that are pushed as facts. I’d like to do that myself.
Don't be a parrot that's funny. So dang you would thing would gain a lot more than that but like you always say that's why we test. I myself am still surrounded by idiots that think oh yeah I think I'd I do this it will make way more power. My way is the right way and I go ok sure in my head lol.
Test some CID heads too