ultraviolet70

I don't get over here to TGO that often, but I know there is alot of knowledge on this forum and alot of experience with the HSR so I'm hoping someone has experience or first hand knowledge with this.
I'm having trouble finding solid info on the capabilities of the HSR.
I know the HSR produced 2006 and later can opened to a Felpro 1206 and be ported to flow in excess of 300cfm, but I can't find any info that tells me how much.?

So I guess what I want to know is how much can one these be opened up to flow?

Whats the largest cubed engine you or you have heard of/seen the HSR sitting on?

How much horsepower can the HSR support (no boost/no nitrous)?

I know looking at the base of the HSR it strongly resembles a tunnel ram manifold, how close would the HSR perform to a tunnel ram?
I can't find a dyno sim for the HSR but running a sim using the tunnel ram I can make huge power, which is what kind of spurred this thread.

Thanks in advance guys for any info/input you can give me on the subject

brians88gta

i believe it will flow 1200cfm and is 50 hp over a tpi at 6500rpm

customblackbird

iTrader: (15)

i beleive it was 2006 or 2007 that holley fixed the problem with the HSR as far as adding more material around the intake ports so it can be ported to the felpro 1206. I did this myself but opening it up to the felpro 1206 doesnt leave much material for gasket sealing. i have maybe 1/8" to seal my gaskets, i wish i would have not had ported it this much but i gasket matched it to the felpro 1206 since thats what my patriot 195cc heads use.

i believe outa the box the HSR flows somewhere around 275cfm but they can be ported to flow more. i would check out this thread
https://www.thirdgen.org/forums/alte...gal-whats.html

there used to be a site called stealthram.com with all the info and compared it to the LT1 and TPI etc with modded TPIs and had all the flow numbers. etc

The HSR is just like every other intake... it can take all the boost and NO2 u can throw at it... the large plenum doesnt really cause any lean conditions at the rear cylinders or anything and since its a closed sealed system theres no issues with running boost or NO2. whats going to limit u is the injector size and fuel rail DIA, the HSR fuel rail kit comes with billet rails that are 1/2" in DIA in the inside... they can support somehting like up to 1000hp. if you go beyond that u might need larger DIA fuel rails but ur deff gona have to match the injectors to the HP output.

essentially the HSR is basically a tunnel ram... they took a tunnel ram and casted injector bungs etc and threw on a plenum and a TB and walla! they flow simular but EFI is a different ball game since TB size and injectors etc play a big role in RPM capabilites not to mention cam/heads and engine displacement. the HSR will make more tq than an LT1 but make more hp than a TPI etc. its like a middle ground between the LT1 and TPI.

Ive seen the HSR on some large small blocks. 383s like mine, up to 400-427s etc. Its a big HP intake that can hang with the big boys. Im not totally sure on the HP it can support since that has more to do with engine displacement and cam/heads. but making 550hp is not really a problem with the HSR. ill be making close to 500 with mine. (ive ported mine and portmatched it as well) This intake would work well with 383 and larger small blocks, since u lose alil low end tq due to the shorter runners, larger cubes will make up for this. not saying the HSR wont work on 350s-355s but they are gona revvvvvv easily to 6500. my 383 will peak around 5500-6000.

ultraviolet70

A flow number like 1200 cfm is relative to the throttle body not the intake. Intake are usually rated per runner not overall flow numbers. For example I know a stock Stealth Ram is rated somewhere around 275 cfm out of the box(rating per runner, but that does not mean it flows 2200cfm (275cfm x 8 runners). Approximate throttle body flow numbers are as follows 58mm twin= 1000cfm, oval monoblade= 1300cfm (but this also does not mean an intake will flow this just because you slap the appropiate throttle body on it (i.e. a stock TPI won't flow 1300 cfm because you put a monblade on it).

Here is the hypothetical build I'm looking at.
Some serious worked over AFR 220cc heads, on a 427 short block with the appropiate cam. I know with a carburated tunnel ram I can make close to 700hp . What I'm trying to figure out is if a Stealth Ram properly prepped and worked over could feed a setup like this and make even close to the same power. I know with those horsepower levels and a tunnel ram drivability is going to be seriously compromised, I'm thinking with a fuel injection/a Stealth Ram and the tunability I could still make this drivable on the street (if the Stealth Ram can support these kind of numbers).

vetteoz

iTrader: (13)

Most of the big cube / big Hp guys are running modded single plane intakes with a 90 degree hat and monoblade

ultraviolet70

I appreciate the reply, and do realize this, but....

If you run sims and analyze the flow characteristics of a tunnel ram manifold more power can be made running a tunnel ram than a single plane.
Now I know a tunnel ram and a Stealth Ram are not he same, but the Stealth Ram is strongly modeled after a tunnel ram.
I like the design of the Stealth Ram and really want to see what can be done with it. So with this thread I'm hoping to find examples of someone really testing the potential of this manifold and maybe I could match or maybe even exceed it.

What I'm partially basing my curiousity on is if you search Holley's catalog. Part number
91406201
brings up a Stealth Ram package that includes 42lb injectors that can supposedly support up to 670hp.
Here's a link at Jegs (Note in the blue box " 575-670 HP Range") or if you search that part number anywhere else you'll find the same info.

http://www.jegs.com/p/Holley/Holley-...61888/10002/-1

Which if Holley rates this to support 670hp out of the box with 42lb injectors and a 58mm twin throttle body, I would think with the right injectors, the right porting and a monoblade throttle body it should be able to support 670hp plus (that being if Holley's ratings are accurate).

Just thowing out what info I'm coming up with and seeing what feedback I get.
Again I value all info and opinions, please feel free to toss out thre what you've got.

formularpm

I would go with the EFI single-plane. Tried and true on lots of big-hp combos...and as a bonus it will also prevent some of the pesky rich conditions on back cylinders inherent in a front-pull intake.

BadSS

I think the StealthRam is great for engines under 500,, and approaching 550 horses with the front feed throttle body. Even at those levels,, I'd be a little worried about distribution problems. Now,,, it's based on the Wieand street series carbed tunnel rams - and you can swap out the plenums. I bought a dual carbed plenum and was going to run dual 750cfm throttle bodies on it,,, but sold the car. I still have the plenum,, and that might be a decent project - dual top fed t/bs - hood clearance would be an issue (lol)

I've built a number of carbed 600 plus HP 406s and a few 434s using the Brodix HVH intakes and 850 annular discharge Holleys that deliver fuel injection type throttle response,,, and that's what I plan on running as a back up to the FIRST project I've started back on. I'm afraid the SS might not break into the 10s with the FIRST,, and I know it will with the converted HVH.

ultraviolet70

Thanks Badss for the response. I've been told to watch for your response and it seems to go inline with pretty much what everyone else is saying "that a single plane is going to be the simplest most effective wqy to achieve the power levels I'm looking for" (to all others that said this as well, Thank you.

Orr89RocZ

iTrader: (20)

I'm alittle late but heres my thoughts.

miniram has support big hp numbers on big inch motors. Has been opened up to over 350 cfm. One that i know of custom cut/epoxied flowed at 400cfm.

HSR is suppose to do 275 out the box. I would not think it be unreasonable to expect 350cfm out of it. Depending on how far you grind. I took mine to only 1205 port and worked the middle alittle bit and there was ALOT more room to go.

Alot of carb manifolds wont do 300 cfm out the box so they all need work.

My street 383 put down 400whp through the 700r4 auto and locked up 3600 stall. Ran 118-119 mph in the heat. Strong motor. Simple AFR 195's and 230 degree cam.
Good news is that it pulled strong as hell to 6800 rpm. I shifted 6600 most of the time. Power didnt drop off from its peak at 6250 to 6500 where dyno stopped. I shifted 6800 and didnt lose much ET at all so it will support lots of RPM

I was gonna go with a 240/243 cam last winter for this summer, but decided to do a twin turbo motor. BUT with that cam i was expecting another 20-25 whp. If i went with proper head like AFR 210's, I would have loved to see 440-450whp.

My buddy's miniram 406 is probly near 475-500 whp based on his trap speed and its a basic AFR 195/miniram/242 TPIS solid roller car. He traps 126-127 on motor, same as my 383 did on a 150shot. HSR i dont think would give up too much over the miniram if anything at all

Largest motor i've seen HSR on with results was a 427 on here that made 500whp n/a. So HSR should support plenty of power.

700hp out of a n/a small block is no small feat no matter what intake/heads you run. Thats a serious motor. I'm not sure how ported those heads are and how big of a cam your thinking but the heads better be something incredible to support 700 n/a power. I think 600-625 is a more realistic street car goal. Thats 500-520's whp through an auto i guess.

There are alot of guys with 408 inch LSx motors making 550whp on a good day so asking a small block to do that is pretty tough.


Like above mentioned, there are some distribution issues with front fed intakes. I saw one on my 383 but not sure if that was an idle low speed condition or general WOT condition. May have been from the wet shot forcing to much fuel in the rear (makes sense based on how fast that spray came out and where my nozzle was) My 2 rears were richer than any other cylinder. If you do go for it, i'd put a bung in the rear cylinders to measure its air fuel ratio as well as front cylinders. Depending on which EFI setup (aftermarket) they usually have sequential type injection to beable to compensate rear cylinders fuel flow to even out air fuel ratios.

Most top fed carb efi setups do not have a problem with distribution but its gonna depend on the casting i'm sure.