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20SS06 01-19-2019 06:42 AM

Help Choosing a Cam for my LSX 454
 
Hi guys,

I have a 2008 Corvette Z06 with an LSX 454, RHS Pro Elite LS7 heads, ID1000 injectors, Fast 102 intake, Comp Shaft Mount Rockers, McLeod Dual RXT clutch.

Last time I got a custom spec cam I got a smaller than desired cam. 236/248 .634"/.634" 117+3 lsa. I went ahead, bought it and installed it. It runs great and strong especially after 4000 RPM till redline @7100. Idles great too. Not stock drivability but very minimal surge at low speeds.

I have plans to build a maxed out streetable NA setup.
What cam will gain me the most power for my setup?
I want a streetable car since all my races will be drag races from a roll to very high speeds.

I know and realize I wont have stock like idle nor drivability and I don’t care. I just want the most powerful streetable setup.

Custom spec cams are a hit and miss based on my experience. What do you guys recommend? Whether it be custom or off the shelf proven cams?

Cam will be a hydraulic roller cam not solid.

Your input is much appreciated.


Che70velle 01-19-2019 09:06 AM

Hydraulic or solid roller?

JakeFusion 01-19-2019 10:49 AM

How does that 236/248 not drive perfect in a 454? What's the LSA?

I'd say 247/261 114+3...

20SS06 01-19-2019 10:53 AM


Originally Posted by Che70velle (Post 20033612)
Hydraulic or solid roller?

Hydraulic

20SS06 01-19-2019 10:54 AM


Originally Posted by JakeFusion (Post 20033653)
How does that 236/248 not drive perfect in a 454? What's the LSA?

I'd say 247/261 114+3...

117+3

Not sure. It has 8 degrees overlap but Im not sure thats why.

spanks13 01-19-2019 11:24 AM

Your fast 102 is going to be a major restriction when looking to max out a 454.

20SS06 01-19-2019 11:32 AM


Originally Posted by spanks13 (Post 20033670)
Your fast 102 is going to be a major restriction when looking to max out a 454.

How major are we talking? And why?

Che70velle 01-19-2019 01:27 PM

I’m running a 254/268 solid roller, which is equivalent to a 247/261 hydraulic in my 434”. Drives great on the street with a tolerable amount of surging at 1700-1900 rpm, but only at no throttle/very light load. As usual, JakeFusion is correct with his info. I could have went bigger...much bigger indeed, but wanted driveability over a 680ish dyno number.
The Fast 102 will be a restriction, even ported, compared to a ported MSD. The issue today is that guys who are going max effort LS7 builds, myself included, are finding even the ported MSD is holding the engines back. Some have tried a highly ported hi-ram and a 108 throttlebody, and found that to be a restriction. The latest experiment is a sheet metal intake with dual openings for dual throttle bodies, similiar to a LME intake, but with longer runners. Your 454 will want way more air than the fast/102 can give it. Gains of 35-40 have been found going to ported MSD.

20SS06 01-19-2019 03:16 PM


Originally Posted by Che70velle (Post 20033711)
I’m running a 254/268 solid roller, which is equivalent to a 247/261 hydraulic in my 434”. Drives great on the street with a tolerable amount of surging at 1700-1900 rpm, but only at no throttle/very light load. As usual, JakeFusion is correct with his info. I could have went bigger...much bigger indeed, but wanted driveability over a 680ish dyno number.
The Fast 102 will be a restriction, even ported, compared to a ported MSD. The issue today is that guys who are going max effort LS7 builds, myself included, are finding even the ported MSD is holding the engines back. Some have tried a highly ported hi-ram and a 108 throttlebody, and found that to be a restriction. The latest experiment is a sheet metal intake with dual openings for dual throttle bodies, similiar to a LME intake, but with longer runners. Your 454 will want way more air than the fast/102 can give it. Gains of 35-40 have been found going to ported MSD.

Yes, my surging is exactly at 1700 - 1900 RPM at no throttle/very light loads. I’m thinking of a 250+ intake duration and 260+ exhaust.

I actually made up my mind on getting a Mamo ported MSD very soon. I am just trying to squeeze every HP I can.
I have also thought about Harrop’s ITB LS7 intake. @70+ wheel hp, that thing is no joke and very well might be considered a power adder LoL. But I will need to change my hood for that. I haven’t seen many posts anywhere about it online. Maybe just a post or two. Thing costs $5000+!!! Is it worth it? Who knows.

Another thing that surprises me is the fact that not a lot of people are running LSX 454s. There is a considerable number but not as much as I thought given that the engine has been around for a while.

All the posts I see are mainly in articles on online magazines. But the way they build them are not streetable at all. I would not, for instance, put a cam with over 1 inch lift. I’m trying to be reasonable too.

The last thing I’m thinking of doing after everything is where I want it to be is add an LS race vacuum pump. That frees up a good amount of power depending on the setup.

For now, the Mamo MSD is number one on my list.

JakeFusion 01-19-2019 03:39 PM

8 degrees overlap in a 454 should drive like stock.

So, it's in the tune. I was able to tune out the light surge with 16 degrees of overlap on a 346. The only place it wouldn't go away was in closed throttle coast down. The overlap would pollute the intake charge at idle condition.

It's off-track, but to fix it, you need to adjust the timing and A/F mix.

And an MSD 103 is going to pick up huge over a FAST 102. But it'll still be a restriction. To the point where I wouldn't look at an LLR or anything like that. Stay Hydraulic. You'll have issues pushing past 7K RPM. You also need 300+cc ports that can push 420+cfm.

20SS06 01-19-2019 04:16 PM


Originally Posted by JakeFusion (Post 20033778)

The only place it wouldn't go away was in closed throttle coast down.

Exactly my case.

What are my options for the least restricting intakes?

Che70velle 01-19-2019 05:27 PM


Originally Posted by 20SS06 (Post 20033797)
Exactly my case.

What are my options for the least restricting intakes?

Check out the dual throttle body intake that I was referencing in my earlier post. Something like this would allow the 454 to get enough air to make power north of 7500 rpm. I’ve been told that the intakes have short runners, but I haven’t spoke to the guys at LME personally about it.

https://www.latemodelengines.com/ind...ld/ls7-bi.html

Che70velle 01-19-2019 05:30 PM

And oh yeah...NOTHING from this point forward Is going to be cheap. The LME unit is like $4500. Big power equals big bucks.

20SS06 01-20-2019 05:01 AM


Originally Posted by Che70velle (Post 20033828)


Check out the dual throttle body intake that I was referencing in my earlier post. Something like this would allow the 454 to get enough air to make power north of 7500 rpm. I’ve been told that the intakes have short runners, but I haven’t spoke to the guys at LME personally about it.

https://www.latemodelengines.com/ind...ld/ls7-bi.html

That looks amazing. But how would this fair with Harrop’s ITB intake since they’re both in the same price range?

and how much better is this with the dual tb than a Mamo ported MSD?


Darth_V8r 01-20-2019 07:09 AM


Originally Posted by 20SS06
That looks amazing. But how would this fair with Harrop’s ITB intake since they’re both in the same price range?

and how much better is this with the dual tb than a Mamo ported MSD?


Whatever you don't go ITB, because I'm going ITB and I want to be faster than you. :jest:

ITB will give great drivability even with a HorseCock Cam

20SS06 01-20-2019 07:19 AM


Originally Posted by Darth_V8r (Post 20034005)
Whatever you don't go ITB, because I'm going ITB and I want to be faster than you. :jest:

ITB will give great drivability even with a HorseCock Cam

LOL

It’s on! Hahaha

are you thinking of getting Harrop’s ITB?

20SS06 01-20-2019 08:37 AM

Was just researching for ITB LS7 intakes and there are a lot!

They are also much cheaper than Harrop's ITB. What makes them $4000 cheaper than Harrop?!

Check them out below:

https://www.ebay.com/p/OBX-ITB-INDIV...S-7/1734017262

https://speedmaster79.com/chevy-gm-l...-system-satin/

http://www.compsystems.com.au/index....whole-ls-range

https://store.jenvey.co.uk/chevrolet...it-ckct05t-kit

Darth_V8r 01-20-2019 10:15 AM


Originally Posted by 20SS06
LOL

It’s on! Hahaha

are you thinking of getting Harrop’s ITB?

I was gonna go with Pantera efi. Do a package deal on ITB and a custom controller.

JakeFusion 01-20-2019 06:46 PM

Hot Rod Magazine Tested an ITB intake against other LS3-based intakes. The Speedmaster IR Downdraft, which is a $2k intake. I don't know the quality compared to Harrop or whatever. But there you go.

But, the Short Runner FAST made the same power and slightly less torque... Holley Hi-Ram beat it overall. While the Holley Sniper, Edelbrock Victor Jr. and Super Victor, and Edelbrock Crossram all were better in power and same in torque (with Crossram beating out even the long-runner FAST).

The new FAST XR/pTR made the most power and torque of anything. And the Edelbrock Pro-Flow XT was right there with it.

Point is, I just don't see this being a justifiable $4k or more upgrade. It is cool and may make tuning of a bigger cam easier. But if you use a newer PCM, tuning a big cam is much easier than the Gen III PCM with it's IAC garbage. But if you cut your cowl to fit the ITBs, you could run a Pro-Flow, Hi-Ram, a Super Victor, or the new FAST XR, and it would make more power. Especially with an LS7 head.

Dyno between a stock LS3 intake and the ITB...
https://st.hotrod.com/uploads/sites/...take-chart.jpg

20SS06 01-21-2019 03:05 AM


Originally Posted by JakeFusion (Post 20034274)
Hot Rod Magazine Tested an ITB intake against other LS3-based intakes. The Speedmaster IR Downdraft, which is a $2k intake. I don't know the quality compared to Harrop or whatever. But there you go.

But, the Short Runner FAST made the same power and slightly less torque... Holley Hi-Ram beat it overall. While the Holley Sniper, Edelbrock Victor Jr. and Super Victor, and Edelbrock Crossram all were better in power and same in torque (with Crossram beating out even the long-runner FAST).

The new FAST XR/pTR made the most power and torque of anything. And the Edelbrock Pro-Flow XT was right there with it.

Point is, I just don't see this being a justifiable $4k or more upgrade. It is cool and may make tuning of a bigger cam easier. But if you use a newer PCM, tuning a big cam is much easier than the Gen III PCM with it's IAC garbage. But if you cut your cowl to fit the ITBs, you could run a Pro-Flow, Hi-Ram, a Super Victor, or the new FAST XR, and it would make more power. Especially with an LS7 head.

Dyno between a stock LS3 intake and the ITB...
https://st.hotrod.com/uploads/sites/...take-chart.jpg

which Fast XR are you talking about? Is it the regular LSXR?
I’m not finding it.


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