LQ9 408 forged need Supercharger advice

Guys saw this post of sand car engine build with dyno run and I am building similar set up for street application.

"408 LQ9 / GM 1.9 LSA Dyno to tune on 91, 11:1 engine
First pull stock ctsv lower crank pulley and the upper 2.55 it made 3 or 5lbs of boost not impressive.
Change the lower out and underdrive it by 7%.
With the 2.55 and the 8-7/8 lower it made 660rwhp at 6400 rpm / 675rwtq at 3800 rpm at max boost of 9.8lbs on the Dyno at 3800 rpm.
LSA turned 23k rpm at 6400 engine rpm. Recommended max rpm for LSA supercharger is 25k rpm and they go boom around 27k I believe."

Difference is 9.5 compression in my street application, question is will OEM 1.9 GM LSA run out of volume with 408 and 9.5 compression?
I don't want to spin it to the moon either, strictly street / fwy application. I live in Cali and actually drive my car in 100+ deg weather and want as little heat as feasible which means spinning blower slower but keeping volume to feed stroker.

Would this combo be better off with more expensive 2650 OR full ported GM 1.9 (joker/boost district sells for 3800 bucks) the difference is about 2,900 dlls more for Kong 2650 priced at 6,500.
Goal: is similar 660rwhp at 6400 rpm / 675rwtq at 3800 rpm at max boost of 9.8lbs but realistically id be fine with 650hp/600tq in the specified RPM range if it translates into the DD Pump gas friendly LS3 manners I had with last 453 rwhp / 412rwtq ls3.

Using as cast LS3 ported heads with 5 angel valve job and btr lsa stg 2 cam.

Why not the Magnuson Heartbeat 2300? I really like those systems.

Andrew

i thought the Maggie 2300 would run out of volume on a 408 lq9, no?
If not the case the Heartbeat 2300 works for me, may even fit under stock hood.
I see its priced at 6k so poses the question if going to spend that much why not 2650 priced the same, more air les rotor spin, less heat, unless Heartbeat is just that efficient to carry 408 with equal or less compressed heat.

Though the 2650 is a great supercharger, it is big and tall. You may want to see if there are dim's available from Magnuson to see if it will fit. The Kong 2650 may be a lower profile option but fitment should be confirmed.

Finally pulled the trigger but have question about compression for supercharged application.
Have new -11 cc Wiseco pistons 4.070 and 64.5 cc heads, stock stroke 3.622 and rod length 6.098, with BTR stg2 Positive displacement cam. 227/242 .614"/.592" 122+6. Im at a static compression ratio of 9.94:1 and a dynamic compression ratio of 8.54:1, is this too much compression for 8-10lbs of boost with intent for 12 lbs on E85?

I'm already to send my knock off LS3 heads(PCE), 65.5cc, to Terry over at Wilkes Perf. for full CNC porting and 5 axis valve job and he said he could easily CNC my Wiseco pistons to -15 cc no problem netting me 9.55:1 static and 8.21:1 dynamic, am I splitting hairs at this point?

Is it better to have more compression than boost to keep timing or more boost than compression and sacrifice timing? NOT an max effort build, strictly street weekend duty 300mi loops. using crappy Calif 91 octane swill and stupid hot 100 degree summer weather (will use octane booster for sure)

Scored a new Whipple 2.9 "hot rod kit" for $5100", picked up 6.0 ls2 bare block for $650 from Steve, owner at Race Engine Dev in Oceanside for full Darton dry sleeves, 4.070 bore, $1995 ttl 2655

I'm running an SBE L92 that comes with 10.5:1 compression stock, stock LS3 heads, stock LSA Blower and lid with a 2.5" upper pulley and stock CTSV lower. I only replaced the bearings in the shortblock and gapped the rings for boost .024/.026. I'm running the Summit Ghost cam 8715 which is a stage 1 boost cam. My car just made 630HP/619TQ on a Dynojet. I'm seeing just shy of 11psi at 3K rpms and it trickles off to around 10 by 6500 rpms.

Going back to your first post about your boost numbers, they seem low for a 2.5" upper pulley/stock lower CTSV combo. I know that boost is a function of restriction, but from what I gather a stock CTSV or ZL1 will make around 8-9 lbs. Usually can subtract around 2 psi for headers, and add around 3 psi for an upper pulley. Also since you have a larger cube motor, you could likely subtract another psi for that. Based on what I've seen, I would imagine that you should see at least 8-9psi based on your setup.

Lots of guys are running 11:1 compression or higher without issues with boost of some kind. It all comes down to the tune.

I had an issue when I first got my supercharger up and running with a low boost situation just like yours. I played around with the bypass which can actually leak down your boost if not adjusted correctly. I then determined that I had a weak bypass valve. I ordered a new one from GM, and that was the ticket. I did the same thing I had been doing, leaving the car in 4th at like 45 mph then hit the throttle to build load on the motor for max boost. Well this time it build 11 psi and spun the tires! Night and day after that. Many LSA guys report seeing a gain of a few PSI by properly adjusting the bypass valve. From the factory they can be slightly open which doesn't give you full boost.

Sounds like you are going in a different direction now, but if you decided to keep the LSA for testing purposes I'd bet your issue is bypass related. If not hopefully this info may help others.

Ryeguy, appreciate the feed back to the earlier post unfortunately that build put rods 1&2 through the sides of the block.
Was too depressing to post about it then ha ha, have since moved on to the build above recently posted, totally different components, could use your eye on the parts selection regarding compression calcs, thx
Darton sleeved ls2 with 4.070 slugs at -11cc, should be something close to 377cu.
LSA is swapped out for 2.9 Whipple
Kept PCE 64.5cc heads but having them cnc ported, just wondering if i shouldnt mill pistons to -15cc or let be.
-11 cc Wiseco pistons 4.070 and 64.5 cc heads, stock stroke 3.622 and rod length 6.098, with BTR stg2 Positive displacement cam. 227/242 .614"/.592" 122+6. Im at a static compression ratio of 9.94:1 and a dynamic compression ratio of 8.54:1, is this too much compression for 8-10lbs of boost with intent for 12 lbs on E85?

:jawdrop:

That's some carnage right there...

So are you saying that RED was able to install Darton Sleeves in your LS2 for around $2k? That's pretty good if it is.

Also, curious why you aren't going for a bigger bore than 4.070" and sticking with a stock stroke?? Having a 2.9 Whipple will likely want more cubic inches I would think. If it's not too late, I'd see if they would do a 4.125" bore. You could keep the stock stroke still to make a 388, but I'd be wanting more inches to feed that 2.9 Whipple. Plus, you will make more power on less boost with more cubic inches. If you went with a 4.125" bore and 4" stroke, you'd have a 427. A 427 with ported heads on 8 psi should be easily over 800 hp. If you are buying an all new rotating assembly anyway, it likely won't cost much more to go bigger. My 2 cents.

IMO, with today's technology your compression could go higher. Lots of guys are swapping LSA blowers on stock LS3's and making a ton of power. I've read that one of the biggest failure points for engines is breaking the piston Ringland because the ring gaps are too tight for boosted applications. I gapped mine per Mahle's instructions for supercharged application and was very pleased with the power I made. I'm at 10.5:1 Static, but I think the LS3 guys are more like 11:1 or even higher. Someone will probably correct me.

I'd say ring gap and your tune are going to be the most critical points to a boosted build.

YUP, caught a deal at RED or would of wound up using an LQ9 I have laying around.
As far as not going 4.125 im Erroring on the side of caution for once in my life not going for big inch build or maxing some thing out haha.
Already had set of forged 4.070 pistons, forged crank and H beam rods from another build project (LQ9) and made financial sense this go around since i shot my mud on a New whipple and sleeve job resulting in no duckets left to score another set of slugs.
I figure stock stroke will keep spinning forces on the bottom end optimal, resulting in piston skirts staying in the cylinder bore BDC, limiting piston rock shortening skirt wear life, not to mention the security of added wall thickness strength when occasionally cranking up boost on E85.
Should I ever score a cylinder bore for any reason, pending total disaster of course, there will be plenty of meat left to over bore.
My goal is longevity since it is truly a daily driver, before torpedoing last engine car saw M-F action 12 mile to and from work AND weekend 200 mile loops to Long beach and New Port beach, not to mention any excuse to grocery get in it, def not a trailer queen or weekend duty only.

Ah, well if you already had the rotating assembly that makes sense. With a fully forged rotating assembly, thick cylinder walls, I'd think you could turn the boost way up and be more than fine. I'll bet with the new supercharger, ported heads, thick cylinder walls you'll be easily in the 700s. Even more if you add e85, but just remember that you need to adjust your tune for more timing to get the benefits of e85. Are you going to add a flex fuel sensor? That's by far the easiest way to add in the power. No thinking about it, just fill up and go. What ECU are you running and what car/truck is this in?

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Originally Posted by MAGONSTERZ68

Finally pulled the trigger but have question about compression for supercharged application.
Have new -11 cc Wiseco pistons 4.070 and 64.5 cc heads, stock stroke 3.622 and rod length 6.098, with BTR stg2 Positive displacement cam. 227/242 .614"/.592" 122+6. Im at a static compression ratio of 9.94:1 and a dynamic compression ratio of 8.54:1, is this too much compression for 8-10lbs of boost with intent for 12 lbs on E85?

I'm already to send my knock off LS3 heads(PCE), 65.5cc, to Terry over at Wilkes Perf. for full CNC porting and 5 axis valve job and he said he could easily CNC my Wiseco pistons to -15 cc no problem netting me 9.55:1 static and 8.21:1 dynamic, am I splitting hairs at this point?

Is it better to have more compression than boost to keep timing or more boost than compression and sacrifice timing? NOT an max effort build, strictly street weekend duty 300mi loops. using crappy Calif 91 octane swill and stupid hot 100 degree summer weather (will use octane booster for sure)

Scored a new Whipple 2.9 "hot rod kit" for $5100", picked up 6.0 ls2 bare block for $650 from Steve, owner at Race Engine Dev in Oceanside for full Darton dry sleeves, 4.070 bore, $1995 ttl 2655

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Id stick to 9.5:1 with the crap fuel and the heat.

More boost/less timing to make the number.

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Originally Posted by ryeguy2006a

Ah, well if you already had the rotating assembly that makes sense. With a fully forged rotating assembly, thick cylinder walls, I'd think you could turn the boost way up and be more than fine. I'll bet with the new supercharger, ported heads, thick cylinder walls you'll be easily in the 700s. Even more if you add e85, but just remember that you need to adjust your tune for more timing to get the benefits of e85. Are you going to add a flex fuel sensor? That's by far the easiest way to add in the power. No thinking about it, just fill up and go. What ECU are you running and what car/truck is this in?

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I'm still running the GenIII pcm, my buddy owns a speed shop locally so I get all the dyno tune time I need, he said no problem at all scaling tables to what I need.
Wanted to upgrade ECM to Holley Terminator Max X but again low on funds ($1700) however I did add a Continental flex fuel module, 1050cc injectors and vapor works return less pwm system with dual CTSV fuel pump, may have to add voltage boost a pump down the road if I max out the pump, wont know till its all together and get a tune in it. Should be a kick in the arse! hoping the wifey gets the Christmas gift hints imma dropping for the Smoothflow boost controller recently out for the whipple 2.9 that way I can tune for E85 at max boost then just dial it back, LITTERALLY, with a turn of the knob when on garbage Calif 91 octane. I know it don't need it but, hell what's need got to do with it any of it! haha

Its all going back into my 68 Camaro Vert.
Attachment 194064Attachment 194065

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Originally Posted by protour_chevelle

Id stick to 9.5:1 with the crap fuel and the heat.

More boost/less timing to make the number.

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More boost less timing was a consideration and still on the table as haven't sent pistons off to get cnc'd from -11 to -15.
I spoke to Paul Williams and of course he likes more timing than boost for street applications stating it will feel punchier on the bottom end where it will live majority of its time.
I always thought more boost less timing as well but of course for the application which is 100 percent street DD he may have a point.

thanks for the input,

Well it happened, the snow ball effect!
Santa was good, got holley max x for Christmass, gutted original PSI harness cleanly from every connections and rerouted Holley harness through original opening.
Wired in Vapor works dual pump, pwm, return less fuel pump system.
Now in the process of connecting all the sources, fan triggers, whipple GM map and IAT, WOT A/C cut out to VA unit and last but least speedo/cruise control signal, etc.... Fun fun fun.
Of course block is still at machine shop for Sleeves so asked them to change up to 4.125 sleeves which means i sent my 4.065's back and re order new slugs, smh. why not at this point.

You'll love the X Max. Just make sure that you have all of the sensors set up correctly in the tune first. @andrewb70, Andrew is the guy to talk to with you tuning needs.

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Originally Posted by ryeguy2006a

You'll love the X Max. Just make sure that you have all of the sensors set up correctly in the tune first. @andrewb70, Andrew is the guy to talk to with you tuning needs.

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I saw Andrews services being touted in a few posts, would it be prudent to have him flash a tune with my parameters to upload prior to first start?
Have been tinkering around in the software and still not clear on the verbiage or some applications.