rskrause....need suggestion on blower cam, long but detailed.

Ok, first off...I must say this buildup has been one hell of a journey. Started as a spun rod bearing and was just going to replace it with stock engine...to a forged 383ci Stroker, S/C and Nitrous injected LT1 project.

Anyhow Ill list all the specs first before anything. I have read many, many posts and know that your suggestions will probably be the 224/236(cause I know the 214 is too small for what I want) Im just not sure if I should go bigger than 224/236 or not. Specs on my setup are:

Forged 383..Eagle 4340 3.75"crank and Eagle 4340 5.7" hbeam rods with ARP L19 bolt upgrades(good for over 1000hp), JE -31cc blower pistons, Hellfire rings, 4bolt studded main caps(3 center ones), Clevite bearings, internally balanced.

My heads(this is where it gets complicated). I will be running AFR sometime down the road to get my cr down some more to really run some boost, but due to major backoder and such...Im going to go with a set of ported stockers to get the car up before inspection/emissions in june. Then over winter(hopefully AFR will get its **** toghter by then) I can install the AFRs(with 64-66cc chambers on the 220cc castings). Till then the stock ported LT1s will have to do.

Specs on heads are as follows: (ported intake/exhaust, opened up cc and polished it as well, Race Flow stock size, backcut valves..and super great 3 angle valve job and bronze valve guide liners, new seals, 612springs(retainers/locks), 1.6pro mag rr arms). BTW...I had another set of ported LT1 heads, but the low-mid #s were not very good and they only had 52cc chambers after major milling to fix the overheated heads.

Lift Intake Exhaust E/I %
.100" 81.6 68 83.3%
.200 145 111 76.5%
.300 200 148 74%
.400 230 173 75.2%
.500 250.2 187 74.8%
.550 257 194 75.5%
.600 258 194 75.1%

Final Average E/I % ratio=76.34%
Finished cc's was 55.5cc after being milled .016"
-I had the combustion chambers opened up slightly on these heads before milling

Felpro Head/Intake/header gaskets, head gasket =.039" compressed height

Block is not zero decked and *estimated* .010" deck height(block is at shop and apart again).

Pistons are the -31cc JE blower pistons(for 5.7"rod, .030"over). I did rough calculations and with my ported LT1 heads(55.5cc chambers) and the -31cc pistons, .039"gasket and .010"deck(estimated via what engine guy said over the phone) gave me roughly...9.1xcr Now what I had wanted, but the wapred heads and milling forced me to lose about 2cc. However, It will work ok till I get the AFRs installed(over winter) Ill be running a good cooler setup and race gas anyhow.

I did the calcuation to find the max rpm I need to reach the full potential with the heads and my 383ci engine(assuming N/A). It came out a little over 6430rpms. So dose that also affect how the blower will make power in that it wouldnt make power over 6,400rpms? Or is that just for N/A since it would make peak power there but be maxed out anything after that in turn chocking the system(thats what I though)?

Anyhow, all the rest of my setup is/will be up to task as well. Twin intank pumps, low independence fuel injec convet and injectors, the street twin clutch, roll cage, tubular Kmember(for extra clearance), Hoosier slicks/15" wheels/skinnies for track, sbc, moser 12bolt, LT headers, true duals(soon when its up and running that the next place it goes)and so on. Ill also be running 104(or higher if I find I need it...local shop can get me 55gallon drums of it) race gas mixed at about 50% with every tank of fuel(94). My car only comes out for shows and races so that wont be too much trouble(only gets about 2k miles a year at the most)

Now for the fun parts...the rest of the setup will be a Procharger F1 with a custom cooler setup(still searching all that now). And Ill be spraying my 125shot of nitrous on top of that occasionally for track use(dont think ill be able to handle that on the street). My overall goals are to have a 9 sec, 140+mph car. I intend on running it around (~14psi, just another atmosphere or so :) to get close to 650rwhp or so(if possible with the stock ported head), but I want to know I have more there if I need it one day...cause that day always comes, sooner or later) . For the most part I want to have at ~650+rwhp with blower/stroker on that modest boost level(for nontrackuse). With the ability to really crank up the boost and spray it to run some easy 9s when at the track :D I would like max power to be made around or a little after 6000rpm, with shifting at or before 6500rpm. Do you think these deisred RPMs are too high or out of wack for my plans/setup?

For the time being...I have to get my stroker in the car so I can pass emissions. Its at the shop right now getting balanced, then Ill get it back put it together and get it up and running and broke in for the s/c(so I dont miss my June inspection, in which im always emission exempt due to low miles. But, If i miss it, Ill have to take emissions again..not good). Then after that little break in period and emissions/inspection(june)...Ill have the funds saved up for the rest of s/c setup(acutally do now for the most part, but still shopping around for the perfect setup) and then Ill bolt that onto the just broken in 383. I got 36# injectors and stuff to keep the N/A 383 happy till the blow and all its mods come mid summer.

So, ::::takes a breath::: now that I typed that book. What cam do you recommend for my setup? I want to stay with XE grind blower cam. But most are very high lift and my heads basically stall above .550" so I would like to keep cam lift that high on both i/e sides. Problem is all the ones Ive seen Combo are either too low lift or too small duration, or too high lift. I guess I can mix and match rocker arms if I have too, but would like to keep my 1.6 arms if possible(and im thinking lift in the .550 range would be ideal for my heads??). If you even made it to the end of this...I thank you very much!

Justin

BTW...pics of my POS can be seen on my site in my sig. Im working on uploading new pics of the stroker sb(thats the 355sb pictured on my site) and all the newr parts not pictured.

Justin: it seems like you are building a "race" car that will occasionally see the street. I assume it won't see a lot of miles and the 1/4m performance is the primary consideration here? If that's the case, you may as well aim for a 7,000rpm redline. Not higher, because unless you left something out, you will be using an OEM PCM.

You will need a bigger cam (than the 224/236) if you are willing to go with a near 7,000rpm redline. Since you will be getting the big AFR's down the road, I think you'd be best getting the cam for those heads, unless you are willing to change the cam when you do the heads? The AFR's won't "stall" until quite a bit higher lift, but I wouldn't advise >~0.600-0.625"" unless you are willing to put up with very short spring life. If you really want max performance from the AFR's you might consider getting a bigger exhaust valve at the expense of a smaller intake. Nitrous + SC is going to make a large volume of exhaust.

My advice follows, but for a project of this magnitude you might want to contact Bret Bauer about a "true" custom cam for exactly what you are building.

Something like CC #3122/3170 would give you 236/248 @ 0.050" lift and .608/.576" lift with 1.6:1 rockers. A 114LSA with at least 4 degrees of advance would work as would the XE lobes 3196/3318 which gives 236/248 and .624/.600". You will need very good springs with either of these.

What about a solid roller?

Rich

Yeah...I guess you could call it that. It does see street time, but I want to favor asskicking, race winning performance on this build. Streetability is number two on this list(but would like to keep as much as I can). FWIW, I plan on keeping my AIR, EGR and all since I have to be able to pass the visual emissions(even when exempt). I will be using the stock computer to do the tuning and will use low indep conv and large fuel injectors. I might upgrade to FASTwhen I get the AFRs and another cam(depending on how high ill be reving). But for now, Ill be using the stock comptuer to tune. I dont mind buying a cam for the stock heads setup...then a cam later for the AFR heads setup. If I was that tight on money...then I wouldnt even be doing this build. Im amazed at how much it has cost me already and im only halfway there.

For now, I want to focus on the stock ported heads setup as far as cam selection goes. Ill worry about the AFRs and thier matching cam this winter.

So what would you suggest for my stock heads setup? I dont mind reving close to 7000rpm(but not over due to stock comptuer) as long as my heads(which by calculation will stop flow increasing at 6430rpm) will not be chocking things(i dont know if that would apply to a FI car or not?). However, I think I would like to make the deisred power a earlier then that(at least by 6500range). Where in the powerband did you make power(rpm wise) with the 224/236 and what heads where you running then? How about the 236/248...any experience with it? It sounds scary huge for my stockers...but if itll work, then Im up for it. What do you think about the 227/239 that combo has? That seems like a good medium betoween the two. I didnt get adversited numbers and/or crunch the numbers at say .200" to compare to other cam makes yet...so I dont know for sure if its acutally a bigger or smaller cam the the other options. I wouldnt mind doing a fully custom cam either. Do you think the Cmotorsports guys are up to the taks as selecing a optimal custom came for me? I wonder about them sometimes based on things they tell different people on here. How about Bret Bauer, how do I find him?

Im willing to swap springs again if thats needed(i have swapped all parts on this project about 2x or more each so far already, lol)...but i dont know what more will fit in my heads without work. Ideally I would like to keep my 612springs(ie less that .600lift) so I dont have to throw much more cash into these heads with machine work, springs, ect....till I go with the AFRs and then swap it all, again. Also, will I see much of a gain if the heads dont flow much past .550, but I run a higher lift cam anyhow? N/A I would think no, but Im new to the FI world....so I am not sure if the same rules apply or not(im thinking not due to always having positive presssure to force the air in!?!?) Thanks for any response I get back from you. I know my novels are a PITA to read/answer. Thanks.

Justin

The CM 227/239 cam sounds like it might work for you, with either set of heads. I am not sure on the lift though, so I don't know if your current springs will work. The AFR spring pockets can easily be cut for a larger spring, at least to 1.550" and probably larger. So once you swap heads there are a lot of possibilities for springs. I don't know how big you can cut the stockers though.

When I ran the 224/236 cam I was using unported AFR 195's and the power peak was 6,300rpm, though it didn't really drop off much up to 6,700, which is as fast as I ran it. As far as rpm range on a blower car vs. an NA car as related to cam duration, I don't think there's a real simple answer. I know from experience though that using a blower does not seem to raise the rpm where peak hp occurs to any great degree. I have thought about this and am not sure why.

Rich Krause

Hi. Thanks for the reply. Here are specs from combo site....227/239 duration, .560"/.577", 114lsa . Lift wise its about perfect for me(due to my heads flow and springs rating to .600). And duration seems to be in about the right range also. Now, Im wondering...what kind of lobe is it ground on? Ill call combo later today(in a few hours) and see what they have to say about that cam. If not, then I think Ill go with your proven 224/236(for my stock head setup)....then swap down the road when the AFRs arrive if the 227/239 wont be efficient enough for now.

I do have another question though about the flow on my heads. I went and dug up the old flow sheet for the heads. I had them tested on every port when they were done. My max average cfm at .550 was 257. Now between there and .600: 2 of the ports gained cfm to about 260 by .600. 3 of the ports stayed the same(257-258 from .550 to .600) and the other 3 dropped silghtly between 2-5cfm between .550-.600. The lowest/worst one is 252cfm@.600, the other 2 are 253cfm@.600

Now, my question is...with a s/c forcing air into the cylinders. Will I have issues running a cam above .550" since a few of my ports lose a few cfm above .550"(although most are = or a slight gain)? I know that turbulant/flow stall air is not good at all for N/A setup...but how will this affect a blown setup running lift into the range of the stall/loss on a few ports? With having positive pressure on the ports waiting to cram air in...I would think its not as big of a deal on a blown setup?!?! Correct me if Im wrong. Sorry for all the question...this is one of my last ones for now ;) Im just trying to decide between lift at .550 or something a little closer to .600. Ill hopefully get this cam selection figured out today. Thanks again, Later!

port stall should not directly correlate to the gross valve lift. Highest port effeciency should be placed at mean piston speed. everything else is just their to get the valve open (for the intake atleast). The biggest trick with a "serious" blower motor, is getting the exhaust valve closed quick enough that it builds cylinder pressure, but still has enough time to blow down the cylinder. Port speed should also be checked at cylinder and port exit if ultimate performance is necessary. Also, their are many alloys availible today that will tolerate large gross lift, at short installed height , with little fatigue. Plus don't forget the old rule of an additional 10lbs of spring pressure, for each lb increase in atmospheric pressure.


Thanks
Dennis

Originally posted by airflowdevelop
port stall should not directly correlate to the gross valve lift. Highest port effeciency should be placed at mean piston speed. everything else is just their to get the valve open (for the intake atleast). The biggest trick with a "serious" blower motor, is getting the exhaust valve closed quick enough that it builds cylinder pressure, but still has enough time to blow down the cylinder. Port speed should also be checked at cylinder and port exit if ultimate performance is necessary. Also, their are many alloys availible today that will tolerate large gross lift, at short installed height , with little fatigue. Plus don't forget the old rule of an additional 10lbs of spring pressure, for each lb increase in atmospheric pressure.


Thanks
Dennis

Agree about the spring pressure. That's why I raised the question of a SR setup. More to follow.

Rich

Ok, well...Im waiting for the guys from combo to call me back. Im going to ask combo this also, but do you guys think I can get away with my 612springs assuming I dont go over its max lift with about 14psi(till i get the afrs)? If they are not going to be enough to fight the psi forces...then I guess I might as well swap them while they are still new and returnable. But, if they will work(remember, Ill only be running this stock head setup for a few months(summer/fall), then swapping to 220 AFRs this winter). Itll be another PITA(kind of) to switch the parts to solid roller setup...but I can if thats my only option out. I really would like to stick with what I already have..if its possible. I dont want to have to deal with the solid roller issues(like checking valve lash, noisy engine bay, possiblel knock sensor problems, etc) if I dont have to. Im looking forward to any other useful info you guys post later. Thanks!


BTW....I just bought a 2003 silver/black Yamaha YZF R1 (from germany, but was originally from the US..guy imported it there with him), its running 9.7s@144mph as it is being shipped(has good amount of mods on it :). I should have it in 9 more days as of yesterday(shipping it next monday via FedEx). This way Ill have a fun ride this summer since the TA project probably wont be completed till late summer/early fall the the rate its going. Just wanted to spread the good news...Im almost more excited about the modded bike then I am about my car project anymore due to it taking so damn long.

Hi. Ok, I have made my decision. I spent a good amout of time on the phone with various engine builders, and places like Cmotorsports, LS1 speed, and a few other common ones on these boards.....Im sticking with hydraulic setup for now.

They all said that solid roller setup isnt needed(even for my application and that most people just way overdo the bottom end of the block). However, this was based on the fact that my car needed to do good at low rpms cause it does see street use. And, I dont plan on reving much past low 6k rpm rang. Anyhow, Im going to use the comp r lifters for now. the Combo guys said that they have run as little as 130lbs seat pressure and as much as 170lbs seat pressure on the comp r lifters and they have seen them fail and withstand both. But they said very few fail anyhow and that just as many solid roller setups fail as comp r lifters(due to oiling problems, usually and low rpms we subject them too. They said so many customers call and say im buiding a race car and go solid roller...then it only sees one track trip and mostly steet miles...in turn, killing their setup cause thats not what it was for and having failing solid roller setups. My car will see just as much street as track(although not too much of either) so the hydraulic is the way for me to go. Plus, I figure if something does fail, go wrong...then this winter when I swap to the AFR heads, I could do solid roller at that time. Should I feel its needed and the hudraulic is giving me problems. Combo said not to run a rev kit cause its a waste of money for my not to high reving setup and not needed with the comp r and 612 springs, but im going to run one anyhow. Just in case a lifter or something does fail, itll be cheap insurance for the expnesive shortblock. If that does happen, then Ill consider a solid roller :cool:

Also, thy said that the 612 springs installed at 1.780 will be enough to take 15psi and their cam of course. They are very, very similar to the 616 for the LS1 they said and the are running both on cars with over 15psi and 700 and 730rwhp. Also, i talked to more shops then just them(but combo is included here)...and they ALL said the "rule of thumb" for boost(psi) and spring pressure is...for every 1lb of boost, you lose 1lb of seat pressure and in turn need 1lb more of seat pressure for each 1lb of boost. NOT 10lbs of extra seat pressure per 1lb of boost like someone said. No wonder I was having an impossible time finding springs with that much pressure, lol. Thanks guys :rolleyes: It makes perfect sense when you look at the numbers.

Anyhow, Im still deciding on if I want to try the 227/239, or go with whats proven to work 224/236. Ill make up my mind in the next few hours(thinking the 224 since I dont want to rev too high and thats about the only difference between them is the 227 will rev a tiny bit higher), cause im mailing my parts back to them today. Finally gonna get this POS together soon(again). Thank for the help you did provide.

I don't think you need a huge increase in seat pressure with a blower car. But 1lb/lb sounds fishy to me. A 2.02" intake valve has an area of over 3^2 inches. So, 15psi will exert ~45lbs of force to the back side of the valve.

Good luck in any case. And those cams are awfully close, so don't sweat it either wqay.

Rich Krause

Hummm...I think I just realized something. I think Im adding putting the numbers together then what mr airflowdevelopment was saying.

Initially, I thought that I would need 10lb of seat pressure per psi on top of the needed pressure for the cam.

ie. 130lbs+(15psi x 10lb)=needed spring seat pressue
130lbs + 150lb=280lbs closed.
As soon as i started to look for that, I quickly realized thats not what he was meaning.

Instead, he means for me to start from 0lbs(including stock seat preassre at ceratin height needed for the cam) and add 10 lbs per psi till you get to your desired PSI(which would also be including the needed pressure for the cam)
15psi x10lbs= 150lbs closed needed spring pressure for total setup(blower psi and cam)

So, this would give us an acceptable numbers to work with and appears to be what he was saying. Now, what if you do it the way everyone else is saying and add 1lb per psi of boost on top of the already known needed value for the cam.

130lbsclosed+(15psi x 1lb)=needed lbs or cam/blower
130lbs+15lbs=145lbs

So, it seems the method that adds 10lbs per psi starting from 0(assuming that is what he meant) and adding 1lb per psi starting from stock installed lbs/height...both come out to be close. Not exact by any means, but no too far apart either(espically since once they break in, they all lose 10+lbs anyhow. BTW, I apologize mr airflow if I misunderstood what you said.

Ok, well...my plans have changed majorly again. I got my heads back today and they got damaged in shipping. The surface areas are alll scratched up(USPS is refunding money cause they were insured). Anyhow, the heads are already at my local shop to get milled some more to fix the damage. Problem is...the combustion chambers will be too small for my setup now(and I can get pistons with any large -cc dish than i have).

So, Im getting AFRs now. I talked to phil from Ai today and ill soon be on the waiting list now, 9-10weeks :(. I have to let him know by the end of tomorrow what ones I want to run/order...then im going to give him my down payment. I was thinking of the 220 race ready version for about $1900, then Illhave to mill them down to 64cc or so. Do you think these will be good for my plans? He also listed the 210 comp port, but they were around $2300 which I dont want spend that much on them(and I want to have extra to work with a year or two down the road). I will cosider the 210race readys if that slight reduction in intake cc size will help my blower setup. Will it? I dont want to get any of the competition port versions cause they charge too much IMO for the little extra they get out of them(and IMO 210 or 220 race readys will provide more than enough cfm for a blower steup as they are)...im just concerned abouthe rev limit potential(how crappy down low power difference is betweenthe two, and effect on boost with the larger intake ports on the blower setup. I think Im going to just go with the 220 race readys, unless someone changes my mind for me.

Originally posted by rskrause
The CM 227/239 cam sounds like it might work for you, with either set of heads. I am not sure on the lift though, so I don't know if your current springs will work. The AFR spring pockets can easily be cut for a larger spring, at least to 1.550" and probably larger. So once you swap heads there are a lot of possibilities for springs. I don't know how big you can cut the stockers though.

When I ran the 224/236 cam I was using unported AFR 195's and the power peak was 6,300rpm, though it didn't really drop off much up to 6,700, which is as fast as I ran it. As far as rpm range on a blower car vs. an NA car as related to cam duration, I don't think there's a real simple answer. I know from experience though that using a blower does not seem to raise the rpm where peak hp occurs to any great degree. I have thought about this and am not sure why.

Rich Krause

Could it be that the boost increases due to the fact that at higher rpms there is less time for the air to enter? even when the S/C is spinning faster not necesarily is pumping that much more flow THROUGH the engine... not sure.. just a thought... Like injectors and duty cycles?

Originally posted by N2OpwrdTA
Ok, well...my plans have changed majorly again. I got my heads back today and they got damaged in shipping. The surface areas are alll scratched up(USPS is refunding money cause they were insured). Anyhow, the heads are already at my local shop to get milled some more to fix the damage. Problem is...the combustion chambers will be too small for my setup now(and I can get pistons with any large -cc dish than i have).

So, Im getting AFRs now. I talked to phil from Ai today and ill soon be on the waiting list now, 9-10weeks :(. I have to let him know by the end of tomorrow what ones I want to run/order...then im going to give him my down payment. I was thinking of the 220 race ready version for about $1900, then Illhave to mill them down to 64cc or so. Do you think these will be good for my plans? He also listed the 210 comp port, but they were around $2300 which I dont want spend that much on them(and I want to have extra to work with a year or two down the road). I will cosider the 210race readys if that slight reduction in intake cc size will help my blower setup. Will it? I dont want to get any of the competition port versions cause they charge too much IMO for the little extra they get out of them(and IMO 210 or 220 race readys will provide more than enough cfm for a blower steup as they are)...im just concerned abouthe rev limit potential(how crappy down low power difference is betweenthe two, and effect on boost with the larger intake ports on the blower setup. I think Im going to just go with the 220 race readys, unless someone changes my mind for me.

Is this on a 383?? i have 31cc dish pistons and are going in with 62cc valves...

TEA Told me that hte competition reay wasn't really worth it and I've been waiting 12 weeks almost for my heads... i ordered the race ready 210 for 1800 including tit retainers... They should flow in the 285cfm range and its cnc.. so all ports should be the same and flow the same which will help a boosted application...

Just so you know... and i am going owth a 224/236 3192/3196 lobes @116lsa as recommended by master richard ;)

What lift of the 224/236 are you going to run? This is for a 383(eagle 4340 3.75"crank/5.7"Hbeam rods with L19rod bolts, Hellfire rings and JE-31cc pistons, felpro gasket(.039) and i wasntn going to deck it before due the cr problems I had with stock heads, but now that Ill have the AFRs(eventually)...Im going to have the block 0 decked also so get my squish/quench height perfect via the felpro head gaskets).

I am holding a spot with Phil for my set of AFR heads, but I didnt tell him what I want yet(still deciding, i need to make up my mind ASAP). I wanted 220s initially, but im thinking itll be too much for my plans since those heads dont flow good till up very high in the lift/rpm range. The 210s however, are starting to look perfect for me. The got decent low numbers for that large cc head, but also great mid/high nuumbers in the race ready form. Ill be purchasing mine in race ready version. I dont think its worth the $500+ for them few cfm extra, espically on a blown setup. Also, most of their great cfm gains are up so high(like .750" lift) that Ill NEVER come close to getting their full potential anyhow. No , matter what I get, Ill have to have them milled(here locally, i get better deal) down to get me to 8.4-8.5cr with my current setup.

Thanks for the info and stuff. Later.

exactly my setup....

i will be using high lift version.. im expecting 650+ rwhp on pump gas