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Discussion Starter · #144 ·
For what they are, they flow like crap compared to the other heads I've seen and this is with the 2.08" intake.. Huge differential between int/exh CFM:
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I don't have any experience with them but the flow numbers look similar to my heads IIRC.

I will share this little gem with you though. I like using this site to compare other builds to what I'm working on. It gives me something to reference when I see what kind of numbers a build produced with what heads, cam, etc.

 

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Discussion Starter · #146 ·
@xxdabroxx I think you sent that to me before too. Thanks !! Yeah, flow numbers don't always tell the full story as the port shape and contour really does affect the total ability as well as the comb chamber and quench areas. I did quite a bit of research AFTER I got the Brodix and found they really flow only about as well as a pair of Vortec heads, maybe a little better but they ARE aluminum so, weight saved, higher compression and boost as well as using E85 can let me run a significantly higher boost pressure than with an iron head, all day long. Another not too well-researched purchase by me, thankfully, Speedway Motors only charged me $10 to return them for shipping via UPS and I have a UPS drop right around the block so all good. I've been calculating potential flow numbers and potential HP/TQ of heads and their flows and the higher the differential between the int/exh, the lower the total potential HP/TQ is. The Brodix and the MAXX heads really don't have that great of flow numbers between int/exh... they'd need quite a bit of exhaust work especially for a boosted motor given they each have well over what I would call acceptable differential. The Brodix with the 200 cc int port flows 261 cfm and has 85 cfm differential at 0.600 and flows 253 cfm and has 82 cfm at 0.500, the MAXX with the 200 cc int port flows 287 cfm and has 88 cfm differential at 0.600 and flows 274 cfm and has 81 cfm differential at 0.500... Again, not the full picture but a good starting point to thoroughly evaluate the flow characteristics of the int/exh potential... I have boxed up the Brodix heads to ship this morning and have purchased the BPE heads instead. Slightly less than the Brodix and I have not seen any bad reviews on them and they flow quite a bit better than a blended Vortec + they're aluminum... a little port and bowl work and they should flow great!


In contrast, the BPE 195 cc int port heads:
200 cc int port @.500 the BPE flows 252 cfm and have a flow differential Int/Exh of 45 CFM
200 cc int port @.600 the BPE have 245 cfm and have a flow differential Int/Exh of 32 CFM

Not needing the 0.600 lift in total valve lift as this will be a blower motor and boost will create atmosphere... so the 28" of water is irrelevant. The focus is on getting the crap out of the engine as easily as it comes in... maximizing the laminar through-flow potential for volumetric efficiency. This is only a 355 motor and not a radical cam so, with the 1.6" rockers, I may see a total intake valve lift of close to 0.500... Maybe...
 

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The pro max heads I think are a good budget head and you can always port them yourself and turn out to be a good head, instead of paying close to 2,000 for any other heads. But it all depends on what you're doing with the car. If you're taking it to the track every weekend or just a street bruiser.
 

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My opinion you are putting too much emphasis on exhaust numbers, even supercharged. The incoming pressure from the blower is going to override any lack in the exhaust port....it would only be a problem if the exhaust ports only went 135-150 cfm max like a stock head....once you get to 190 cfm on a 1.6" valve it is going to be good enough to not matter.

Get it too good and you just end up blowing good mixture out the exhaust during overlap.
 

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[QUOTE="Stroker Ace Ventura

Check out the info on brodix web page on track 1 series heads flow chart vs promaxx heads flow chart all at @ 28" water.
The promaxx heads flow better even on the exhaust side .
Let me know what you think. Can't copy it you have to go on their site. 1240.00 compared to 1700.00. The 1240.00 price is for the promaxx solid roller spring heads, with the big 2.08 valves. I'm thinking promaxx is the way to go for me anyways, and save 500.00
 

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Discussion Starter · #154 ·
My opinion you are putting too much emphasis on exhaust numbers, even supercharged. The incoming pressure from the blower is going to override any lack in the exhaust port....it would only be a problem if the exhaust ports only went 135-150 cfm max like a stock head....once you get to 190 cfm on a 1.6" valve it is going to be good enough to not matter.

Get it too good and you just end up blowing good mixture out the exhaust during overlap.
I hear ya, just trying to keep my boost down on the exhaust side by flow rather than compression. I do know that I lost 2 psi just swapping out to a different muffler on my Lightning and even more when I changed the restrictive factory wye to a smooth merged collector so... I ended up with only about 7 psi from the previously-measured 10 psi and the power stayed the same in both HP and TQ. If I can reduce the restrictions on the exhaust, I can also reduce the boost and still make the same power, or relatively close to it without so much detonation and final compression ratio based on mechanical CR + boost. I do hear you and agree, but again, this is an experiment and if I flow well on both sides, I can better calculate final CR and know flows will be more equalized on the exhaust to intake. Still gotta port-match both in/ex too so that'll be a good bit of laminar increase too. Sorry it took me so long to get back with you, been slammed with work and projects due for the state so... fun must wait and I've been working on our pop-up trailer trying to get it completed before our coast trip in two weeks. I have a lot to do :p ... Oh, and The Governor's Cup last weekend.. YAY!!! NOVAS EVERYWHERE!!!!!
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Discussion Starter · #156 ·
Good time until first run after the sun went down on a low 9 sec Nova. Woman lost traction on second nitrous stage and lit up about mid track, couldn't correct and went through the K-rails, big boom, big fire, extrication and fir truck response. Closed the track for hours. Not sure of her final condition status still.
 
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