Slant Six Forum :: turbo header build

IN MY IGNORANT opinion, that cam would be better suited for a normally-aspirated engine than a turbo. It seems to me to have waaaay too much duration for a turbo application and that will result in too much overlap, which will allow too much boost to be blown out the exhaust. The numbers for that cam were 240/250@ .050"-lift which compares with 210/220 for most successful applications I have read about. The cam in our turbo car has 210/210 and displays performance and driveability manners that do NOT cry out for more duration. I think the boost takes care of that, (cylinder filling) and we only are running ten pounds at this time. Also, the lobe separation angle... I'd like to see it increased to 115-116 degrees in this instance. Insurance against losing boost out the exhaust on ovelap, and smooths the idle while fattening up the mid-range torque.

Author:	73Sam [ Sat Jul 06, 2013 12:17 am ]
Post subject:	Re: Camsfat specs
Quote: RE: "the OCG 270in 280ex 112deg LSA turbo cam and lifters (still need installed) $160.25." Can you elaborate on the specs of that cam, please. I want to make sure I have correct information before I comment. Thanks, Bill x2. Id like to hear more about it. I haven't heard of a turbo cam being available for the slant 6.

Author:	Volare4life [ Sat Jul 06, 2013 7:27 am ]
Post subject:
its the 977 cam grind from OCG that i had ground on 112LSA as per their reccomendation -Mike

Author:	billdedman [ Sat Jul 06, 2013 8:50 am ]
Post subject:	Cam recommendations
Mike, Thanks for posting that chart; I appreciate it. Please understand that I am anything BUT an expert on this subject, having VERY little experience with slant 6's and even less with turbochargers. TaKe what I say with a grain of salt, please... I probably shouldn't even be commenting on this subject due to my lack of experience. Having said that, I'll offer my opinion because I'm anxious to find out what some of the more experienced builders here on this board will have to say about it. There are a LOT of guys here who are eminently qualified to speak on this, so I hope they'll chime in with opinions and recommendations. IN MY IGNORANT opinion, that cam would be better suited for a normally-aspirated engine than a turbo. It seems to me to have waaaay too much duration for a turbo application and that will result in too much overlap, which will allow too much boost to be blown out the exhaust. The numbers for that cam were 240/250@ .050"-lift which compares with 210/220 for most successful applications I have read about. The cam in our turbo car has 210/210 and displays performance and driveability manners that do NOT cry out for more duration. I think the boost takes care of that, (cylinder filling) and we only are running ten pounds at this time. Also, the lobe separation angle... I'd like to see it increased to 115-116 degrees in this instance. Insurance against losing boost out the exhaust on ovelap, and smooths the idle while fattening up the mid-range torque. Your build, from what I could tell, is a pretty mild one and a milder cam is called for. The wonderful thing about turbos is, if you're not happy with the level of performance you're getting, a simple twist of the waste gate boost-adjuster can fix that... Like I said, this is coming from someone with NO credentials to give advice, so take it for what it's worth.... probably nothing. But the numbers seemed so far off from what I was expecting, I had to say something, even if it is wrong... Let's see what some of the "old guard" has to say about this. Thanks for listening and good luck with your project; it sounds like FUN!!! Bill in Conway Arkansas

Author:	billdedman [ Sat Jul 06, 2013 1:54 pm ]
Post subject:
Quote: its the 977 cam grind from OCG that i had ground on 112LSA as per their reccomendation -Mike Please note that the #977 cam to which Mike refers is NOT the one highlighted on the chart. Bill

Author:	DusterIdiot [ Sat Jul 06, 2013 2:17 pm ]
Post subject:	No Bill you're correct...
Quote: IN MY IGNORANT opinion, that cam would be better suited for a normally-aspirated engine than a turbo. It seems to me to have waaaay too much duration for a turbo application and that will result in too much overlap, which will allow too much boost to be blown out the exhaust. The numbers for that cam were 240/250@ .050"-lift which compares with 210/220 for most successful applications I have read about. The cam in our turbo car has 210/210 and displays performance and driveability manners that do NOT cry out for more duration. I think the boost takes care of that, (cylinder filling) and we only are running ten pounds at this time. Also, the lobe separation angle... I'd like to see it increased to 115-116 degrees in this instance. Insurance against losing boost out the exhaust on ovelap, and smooths the idle while fattening up the mid-range torque. No not ignorant, this is all logical, the boost is making up the volumetric efficiency that NA builds only gain with compression and intake reflection tuning....the more duration of the cam increases the overlap event which in NA would bleed down the high cylinder pressure allowing the engine to reduce detonation, and help promote scavenging with the headers. Even running a really wide lobe separation high duration cams can have overlap events that are still much wider than the smaller cam with a narrow separation...if the overlap event is too long the boost will push most of the mix right through the chamber and in to the exhaust. I use the 549 cam in stock format (112 LSA) since the hyperpak intake is sensitive to intake reversion so the overlap event has to be controlled to prevent this...even at 112 the 250/250 @.050 cam has an overlap of 55 degrees or so (which works great for 11:1 comp to overcome the bleed down, but is open enough to let the headers pull extra mix into the cylinder, but sacrifices manifold vacuum that it won't be a daily driver...)...for a turbo I would expect the overlap event to be in to the 20-30 ball park like the smaller stocker/RV cams so the exhaust closes sooner and the cylinder can be packed...(Theorhetically it makes the case for a cam I had used but disliked for NA use the Comp Cam Xtreme 256...which was like the little 252 cam but had a .466 lift instead of .435...would provide a little more opening for the boost if needed, but in NA the cam only liked high end rpm and was not so good for street use...overlap was only 26...) I'd be toying with the idea of the 609 at 110-112LSA if I were to do a turbo engine, based on posts garnered here and from other sources in my library, moderate lift, very low overlap. -D.Idiot

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turbo header build https://slantsix.org/forum/viewtopic.php?t=51347	Page 2 of 3

Author:	Dart270 [ Sat Jul 06, 2013 3:08 pm ]
Post subject:
I recently ordered a 224int/219exh @ 0.050" w/113 deg LSA cam from Oregon. I have the MP 0.436" cam in there now, and this one is about the same overlap, but a bit more lift and duration (esp int). I agree that anything much over 220 @ 0.050" will not work as well or will make power up where we don't want to spin a 225. Lou

Author:	ceej [ Sat Jul 06, 2013 7:18 pm ]
Post subject:
Just so everyone knows, there are links to the OCG cams in the FAQ attached to the Engine part of the forum. CJ

Author:	Volare4life [ Mon Jul 08, 2013 8:38 pm ]
Post subject:
..... well thats a bit frustrating, for me atleast, I talked to the guys there, broke down the build, and layed it out as clear as i could, and thats what they recommended to me, so i went with it, I was planning on running the stock cam and lifters for now, not sure if she has an exhaust leak or its the 3" exhaust dumping straight down but she sure is noisy as hell lol I will take her for a spin tomorrow if i can, debating holding off on the intercooler piping kit till after i get back from deployment, can't see the sense in spending $120 on IC piping for a car my wife refuses to drive, and at this time would not accommodate our nearly 2yr old son lol, damn gutted race car lol

Author:	RyGuyTooDry [ Mon Jul 08, 2013 8:57 pm ]
Post subject:
What about the ocg 645? Wide lobe sep (114), not too high of a lift (.444), BUT the duration is a little bit high (228). If you had engine builder valves with a big intake and carb, that would be a great turbo cam. It'd be good to spin up to 5500 - 6000. Just my 2 cents, -Ryan

Author:	Volare4life [ Fri May 02, 2014 8:37 pm ]
Post subject:
well back from deployment, spent some me time and money, that about another $800 in parts and tools, mostly parts lol new ryobi sawzall/drill combo kit new aeromotive 13301 bypass FPR new aeromotive stealth 11140 340LPH FP 1/2" aluminium "return" line 3/8" steel "fuel" line new carb feed line with ss flex and hardline fittings in -6 various -6 and -8 fittings to plumb the system Spa Turbo adjustable wastegate new 2.5" 90* silicone IC piping elbows New 23"x11"x3" with 2.5" inlet/outlet bar and plate intercooler new AEM wide band got a 64-99 jet kit from the local speed shop Spectre filter for the 4" turbo inlet FREEEEEEEE aircraft 10micron w/-6 fittings choke horn is gone, ported mainbody for better flow now time to make sh!t happen !!!

Author:	billdedman [ Fri May 02, 2014 10:15 pm ]
Post subject:
Welcome back!!! And thanks for the nice write-up on the progress you've made in acquiring the parts and tools necessary to get this baby on the road! Looks like you have done a lot of research and really have your homework under control, so please keep us notified of the progress you're making on this project; we are vitally interested!! The more details, the better! Thanks, Bill PS Some details on the drive-train??? If they were posted earlier, I must have missed them..

Author:	Volare4life [ Wed May 07, 2014 8:31 pm ]
Post subject:
small up date, waste gate welded shut on turbo exhaust housing and a jig i set up to cut the pipe at an angle for the new external waste gate hopefully more soon

Author:	billdedman [ Wed May 07, 2014 10:13 pm ]
Post subject:	More progress..
Thanks! I continue to be impressed that you don't seem to miss a TRICK in this build (the angled waste-gate pipe.) Keep on keepin' on; you're doin' GREAT!!! Bill, in Conway, Aekansas

Author:	Volare4life [ Sat May 17, 2014 7:29 pm ]
Post subject:
lil more updated got the external waste gate elbow welded up manifold isn't super straight gonna hit it with a belt sander to try and even it out tomorrow its easy to mock everything up when its not on the car too lol and how it currently looks

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Author:	Volare4life [ Sun May 25, 2014 6:35 am ]
Post subject:
got turbo mani wrapped with titanium lava rock exhaust wrap, had to take it off couldn't fit stupid triangle washers on 2 of the bottom studs, looks pretty don't it