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2005 Cadillac CTS-V
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Discussion Starter #1
Hey Guys. Well, I finally got my car dynoed at Livernois Motorsports in Dearborn, MI. They have a dyno jet, I think the only one in Southeast Michigan. They did three pulls and the best RWHP was 376 and the best RWTQ was 380. The dyno guys were quite taken aback and said they didn't think I'd get those numbers without headers. So I achieved a 35rwhp gain (440hp) from installing Random Technology high flow cats, Volant Cold Air intake, a VMax ported throttle body and mail order tune. It made my day!
 

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Discussion Starter #4
rand49er - what other performance/raceshops do you know about/recommend? When I googled dyno shops in my area the only one listed was Livernois Motorsports in Dearborn. I live in Rochester and it took me an hour to drive there. Is there anything closer?
 

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2016 ATS Premium 6-spd MT
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Rich Gala at what is now Motor City Speedonline in Wixom is who I used, but at that time (May '07) they were Wheel to Wheel Powertrain in Madison Heights. Wheel to Wheel bellied up and some of the guys there, including Rich, formed Motor City. It's not much closer to you, but I know Rich Gala is highly capable.

http://www.motorcityspeedonline.com/#!dyno/c1wko




Historical fact: For the old timers here on this forum, Rich was forum member/moderator/V owner/curmudgeon "Florian's" roommate in college ... if that matters at all to you.

Florian was hilarious in his very to-the-point posts and was even "awarded" with his own smilie: :florian:

Sorry. Just reminiscing a bit this morning.
 

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That sounds right. I didn't go ported throttle body, but headers with no cats, catback, intake and tune and got 41.

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Where is that g00b, Florian, anyway?
 

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2005 CTS-V Maggied
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rand49er - what other performance/raceshops do you know about/recommend? When I googled dyno shops in my area the only one listed was Livernois Motorsports in Dearborn. I live in Rochester and it took me an hour to drive there. Is there anything closer?
I'm near you and I went to Dr Phil. He does his dyno work out of Jake's automotive. Great guy to deal with and awesome tuning skills. He is well renowned throughout the LS community.
 

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I'm near you and I went to Dr Phil. He does his dyno work out of Jake's automotive. Great guy to deal with and awesome tuning skills. He is well renowned throughout the LS community.
There you go, Derek. More than one to choose from. Make sure you post up your results.


... Where is that g00b, Florian, anyway?
Didn't he transfer (demoted?) as moderator to something like the Catera section of this forum or whatever?
 

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Discussion Starter #9
Thanks for the other dyno shop leads in my area - Jake's, for example, is 25mins from my house compared to the hour drive to Livernois Motorsports. Glad I asked. So, anyone want to guess how much additional horsepower I'd get if I pulled my heads and had them ported (plus new valve job) - the two shops I talked to said WITH headers I'm looking at a good 40-50hp gain but I'm wondering how much I'd sacrifice w/out headers? I was really, really close to saying to myself just get the headers (along w/the ported heads) and be done with it, but I really don't care for the sound (I know, I'm weird). I'd like to get to 400rwhp - I'm currently at 376rwhp - would ported heads get me close to 400rwhp? What do you guys think?
 

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ported heads would easily get you there without the headers. Yes you would gain a little more with them but not more than 10 HP at peak levels. Most shops I have talked to and read about say on average 30 HP out of simple ports and cleaning of the valves.

BDV
 

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Discussion Starter #11
Thanks BDV - the heavy wrenching involved in pulling the heads is worth it to me seeing I have 155k on the engine and need a valve job anyway and a 30rwhp gain accross the powerband obviously has tremendous appeal too. It'll be my next project when time/money allows. For now, I'm just going to enjoy the car as is.
 

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... I really don't care for the sound ...
Putting headers on an otherwise stock Gen 1 CTS-V (LS6) plus a tune netted guys between 20-25 rwhp "back in the day." I never baselined my car when stock, but most guys (again, "back in the day") were seeing about 320-325 rwhp (stock LS6) on DynoJets. I did dyno my car (DynoJet) after the headers and tune and saw 350 rwhp (SAE corrected), so that seemed to be in agreement with others.

If you're already at 376 rwhp, I'm not sure what effect headers would have for you. They do sound borderline uncivilized, so I can understand you not caring for them.

I haven't read much about ported heads. If you do them, be sure to post up a thread on your results.

Just to belabor it a bit more, my theory is it all depends on what it is about a particular engine's layout and the air flow into, through, and out that's dominates as the limiting factor. There can be only one at any one point in time, though everything may be in close balance so affecting the one that limits you may not get you much. Could be too much turbulent flow in the heads or some other kind of restriction in there that's choking your motor. In that case, porting will have a beneficial effect. In my case right now, I know where the restriction is (78mm TB), but I've chosen to not pursue modding it. It would be my luck to trade off the reliability I enjoy now for a "walk home" event. I'm getting too old for that. :D
 

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I have looked into ported heads quite a bit myself. it will be one of the big power mods i do with a cam hopefully by next summer. need to pay a few things down so I can free up more money for it. I know a guy local to me does head and cam packages starting at 1150. The heads are worked over and ported and a valve job is done and new double springs are put on for 800. The cam is the rest of the price. I know there will be some other odds and ends like gaskets and pushrods and whatnot. I also want to do the old TPIS 90 mm LS6 intake and get a LS2 TB or have at the very least mine ported and polished up to optimize it as much as I can.

BDV

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and his HP numbers of 30 or so are for his stage 1 setup. With step up in stages he uses larger valves which in turn gives more power but he doesn't port them anymore than he does in the first stage.

BDV
 

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Discussion Starter #14
So I've decided I will go ahead and get my heads ported by Advanced Induction this Spring. Now I have the challenge of knowing when to stop the "fine-tuning" - the bigger stuff...I'm not going to upgrade the cam (check) and I'm not going to install headers (check, side-stepping that one). Now for $400 these guys can port the stock LS6 intake manifold for a gain of 8-12hp. I'm on the fence on this one and would like to get the opinion of you guys. I guess the question is this: with the increase in airflow from the ported heads where does the restriction truly lie in the intake manifold, the throttle body and/or intake manifold itself? I've already ported my throttle body which I personally think attributed quite a bit to my solid dyno numbers (although I have no way of proving this) so I guess I'm wondering how much of a restriction the stock LS6 intake manifold is with ported heads and/or if the $400 price tag is worth it. As an aside, I found a guy that will port (not hone) my stock exhaust manifold to better match the airflow of the ported heads which is a no-brainer for me and only $125. Anyway, any thoughts on whether to port the intake manifold or not. I'm thinking not because I don't have a blower and I'm thinking the stock intake manifold flows pretty well...
 

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An alternative would be a FAST 90 intake manifold. There's one eBay right now, but with three days left it's already up to $615. You'd need a cam plus valvetrain alterations to take advantage of it I'd think:

http://www.ebay.com/itm/Fast-90mm-intake-manifold-TB-complete-LS1-LS6-/121571790276?pt=Motors_Car_Truck_Parts_Accessories&hash=item1c4e3e4dc4&vxp=mtr

So, $400 for a ported LS6 int man would seem less expensive, though I don't know the flow comparison between the two.

Not sure if I've ever heard of someone porting the OEM exh mans ... sounds interesting.

I doubt your 78mm TB is your restriction especially if its ported. Heck, I'm running an unported one and with the maggie I'm drawing about 40% more air through it than you.

Finally, I'll be the first to admit that I lack empirical experience in all this. Be interested to see what others think.
 

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So I've decided I will go ahead and get my heads ported by Advanced Induction this Spring. Now I have the challenge of knowing when to stop the "fine-tuning" - the bigger stuff...I'm not going to upgrade the cam (check) and I'm not going to install headers (check, side-stepping that one). Now for $400 these guys can port the stock LS6 intake manifold for a gain of 8-12hp. I'm on the fence on this one and would like to get the opinion of you guys. I guess the question is this: with the increase in airflow from the ported heads where does the restriction truly lie in the intake manifold, the throttle body and/or intake manifold itself? I've already ported my throttle body which I personally think attributed quite a bit to my solid dyno numbers (although I have no way of proving this) so I guess I'm wondering how much of a restriction the stock LS6 intake manifold is with ported heads and/or if the $400 price tag is worth it. As an aside, I found a guy that will port (not hone) my stock exhaust manifold to better match the airflow of the ported heads which is a no-brainer for me and only $125. Anyway, any thoughts on whether to port the intake manifold or not. I'm thinking not because I don't have a blower and I'm thinking the stock intake manifold flows pretty well...
The stock LS6 manifold will lob flows above 265 cfm, which is good fit with stock 243 heads, but not a particularly good fit for the flow rates one would expect from competently CNC'd 243 heads. So, if you've got the coin, you should consider upgrading the intake manifold with the heads. Because the reworked heads increase flows at lower valve lifts (sub-265 cfm zone) you will still see gains with the stock LS6 manifold. With respect to the exhaust manifold modification, I would not expect large gains unless the existing port match is off by a considerable amount, or the process will increase flow capacity (internal diameter) of the entire length of the cast-in primaries.
 

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Discussion Starter #17
Thanks Rand49er - the guy that can port my OEM exhaust manifold, if I understand him correctly, said he uses the stock manifold gasket as a "template" and smooths off all the factory edges/corners of the eight openings so there isn't any restriction/lip disturbing the (increased) air flow. Heck, for $125 I figure there's no harm in having him take a little bulk off those entrances to increase flow - he said you'd be surprised how much HP you get from something as simple as this. I'm basing this mod on the fact that by simply replacing our OEM manifold with a stock LS7 manifold (if you could get it to fit in the engine bay) would yield us an additional 15rwhp. If I can gain 10rwhp by porting the stock exhaust manifold I'll be happy.

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Just read your reply, Darkman. Okay, so conventional wisdom says if you are increasing air flow as much as you do with reworked heads, it follows that increasing the air flow of the stock intake manifold to match would be wise/prudent. I seem to remember you saying on another thread that the reworked heads will be pushing the stock intake manifold to the max so a ported throttle body probably isn't enough to handle the increased air flow...
 

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Your stock 243 cast heads should flow about 255 cfm at 0.550" lift (stock cam valve lift), which is below the 265 cfm the stock LS6 intake can flow. I would expect your reworked 243 heads to flow about 300 cfm at 0.550" lift (which is the lift of the stock cam) and to flow at least 265 cfm (the LS6 intake limit) at every lift at or above 0.400." You might want check these flow rates with someone at Advanced Induction and asked them what the ported LS6 intake will flow. (Even a ported FAST 102 will have trouble hitting 300 cfm).
 

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Discussion Starter #19
So if I don't port the intake manifold does this translate into me not getting peak horsepower at high rpm's (the 8-12hp) or will I lose some torque and horsepower on the bottom end too? I can live with not squeaking out an extra 10 hp at 6,000rpm but if I'm losing power under the curve as well, I might feel differently.
 

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The shortfall caused by the more restrictive intake will occur throughout the rpm range. After all, the valves travel through the entire range of lifts (0"-0.550"-0") with each cycle regardless of rpm.
 
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