Hey guys, been a member here for like 14 years now which is wild...haven't posted in a bit since the FB groups got so popular but I miss the genuine input. I'll try to keep it from being too longwinded. I've searched at length and NOBODY runs this combo it seems...or cam.


Have a 2003 M6 Coupe that I had put together a blower setup for about 5 years ago. Build was an SBE LS1 with stock 241s. Ayruns (CCP/BTR) Jam Cam, BTR spring set / pushrods, CHE trunions. Stock LS6 intake. Paxton Novi2000 with a flip drive, 10 OD IW balancer, 3.6 upper. ID1000s, Dual Stage Alkycontrol, ECS stage 1 fuel with ring and hobbs activated AEM 380 (iirc). ECS race core with Turbonetics Godzilla, Full exhaust, twin disc blah blah. The car was tuned at Hutter Performance on a Mustang Dyno where we had to really dial things back to live while making our own restrictor plate, dyno with the hood down and limit rpm and timing. In this configuration it made 573/495 with obvious room to grow.


Appx 2 summers ago it finally broke the #7 ringland from a semi-loaded 40 roll in 2nd. Probably too much load too low in the rev range. I ended up purchasing a built longblock that was intended to road race with the idea that I'd make it work for my application. I am now considering just running the car N/A and using it shoot for the magic 500whp on motor with a high goal of 520-530 but unsure if worth the squeeze.


Setup:

372 cui stroker

L33 based 5.3 block (bored)

3.9" BTR forged crank (.0016-.0023 clearance range on mains, .024/.026 rods, .002 thrust)

6.125" ProLS forged rods

3.898 DDS forged pistons -3cc (.21/.24 current gaps, .051 compression height , 001 deck)

ARP studs, rod bolts etc

HV oil pump with double roller chain

Improved Racing windage tray (and Dan Olsen fab F body pan that I don't think I can use)

Cam is a BTR LS3Stage 5 V2 - its aggressive - .235/.25x .646/.646 at 111

Currently wearing STOCK 799 heads with BTR .660 platinum/Ti duals with BTR shaft mount rocker setup - From the advertised compression via DSS, it should be appx 11.18:1

GM LS7 lifters


The estimated power production was to be around 470-480whp as its completely fresh at current. My original intentions were to open up the ring gap, slide in my Jam Cam and run a AFR Mongoose 230 v2 72cc head for @10.2:1 static, remove my restrictor plate and just let it eat. Leave the LS6 for now but maybe upgrade? Guessing that would land me somewhere in the 7-750whp range. The old setup could be a lot on the street at times. Its a street /strip car that might see the track once a year or so. Random pulls etc and Mexico.


I am strongly considering going back to N/A to make it more handling focused, losing the annoying drop cradle and keeping it a bit more simplified in packaging. BUT, I know I'll miss the noise, the civility (maybe?...I like rowdy and have multiple cars, but I would like to drive it more). I think a good balance of having power, traction and the above lands in that 520-530 range and in hindsight wouldve been easier achieved with an ls3 / 4" bore setup to take advantage of the heads.


I DO think having a high rpm screamer would be just as fun as the blower and I can wail on it without worry forever, My intial ideas were:


Run the shortblock AS IS with the big cam, add a pair of 62cc heads at either a 215 or 230 cc TFS or AFR head, BTR trinity / shortrunner and spin it to 7,500-7,700+. Would it make the numbers at 11.5:1 and 93? I keep hearing a 3.9 rod will soak up some of that cam to tame it, but its also slightly smaller bore than an LS3. Would be swapping out injectors / fuel system for smaller. Could potentially run my speed density UICP as a 5" intake or back to a Vararam.


Decisions, decisions...fell free to discuss, call me an idiot. If you want extra details just ask incase I forgot something. Car doesn't have to be insane. High 10s on motor and more handling sound appealing.


-Tom

 

Pics for attention...nobody just likes words anymore.

 

You have my dream garage, just change the viper out for a gen 4. beautiful cars dude for real

 

tight

 

Ha, thanks! Missing 4 there 😅

 

I don't usually cruise the Tech page anymore but this one caught me right away.

Interesting dilemma. I've b en in a similar one having yanked the F1R off the 427 and having the tt402 stuck mid build.

I feel for NA, the cam intended for the LS3 and 11.18cr and ported heads will shoot past your power goal a slight bit. If a ripper is what you want I say send it. No worries. Mash the foot. Instant tire smoke.

As for SC... The jam cam is considered old tech now. I have a fresh one oiled and bagged, perhaps one of the final new ones produced. BTR and their spintron found ways to make more power with lower specs and keep a more durable valvetrain I hear.

The weight of a blower and the drag of the belt/head unit is one thing I suppose.... But once they kick in you don't feel the weight at all. Maybe a split personality is the answer. Hotter cam and run two BOVs like wastegates to tool around without boost or st a set boost. And then when you want to get rowdy cap em. I'm setting up Mac valves on my turbo car to let the R3 run boost by gear and maintain traction strategies as well. The same principle applies here. But run the "wastegate" before the fmic so when it cycles the air in the system has room to smooth and not be fluttering pressure at the throttle body.

The only downside would be the constant vacuum cleaner wooshing noise of a supercharger running at steady rates.

Option C: sell the blower kit, keep displacement small to allow full ranges of use, go turbo and keep it or them really small and responsive. Whole new adventure. I will say however that a blower is a lot simpler to toss on or off. They just suck that extra 100 or 200+ hp from the engine to turn them depending on power level.

 

Oh god... It's you.... Just sell the thing already

I don't like undersquare motors, especially undersquare ls motors. I know we talked a little ways back about your choices.

I would either do another ls1/6 based motor with a slight dome piston... A tfs 215/220 with some slight port work, lighter valves in them (intake side, turned down ls3 hollow stem). Get the compression around 12.5:1, that way you can run 93 still or E85.

Remember my car made over 500 wheel when it had the ls6 still and I shifted it around 7800 with the hi ram. This was with the power peaking about 7k. Mine had the original stage 4 btr ls3 cam (233/250 615/596), so the stage 5 or whatever would get you there.

I am unsure on the trinity, but staying cathedral port really doesn't give you much options (unless you let me cut your hood ). I still shifted the car at 7400 or so when I had the fast on it. Biggest thing to pay attention to is the valvetrain and making sure it is solid, but lightweight.

I really need to take you for a ride in mine at some point when the weather gets nice out.

 

If I'm reading this right, the OP is running a 3.8980" bore and a 3.9000" stroke. It may be considered technically undersquare, but-WOW-By .002"???? That amount of undersquare wouldn't amount to a piece of ant **** at the bottom of the deep end of an Olympic size swimming pool!!! Yes, there are other ways to achieve a 372 cubes with a bigger bore and shorter stroke. But the power difference would be virtually non existent for what the OP is doing, and would cost thousands of $$$$ more. Unless he's planning on running 7,000+ rpm 99% of the time, it would be a huge waste of money. My opinion.....

 

Ha, yeah it’s basically exactly square but with a longer stroke which should make better torque on the street.

 

Oh this car should’ve left my possession a decade ago but here we are haha.

I really don’t consider it under square, it’s basically exactly square. There’s never much actual tech talk on FB just regurgitation and it seems here is a bit dead anymore from builder standpoints. Figured I might catch an opinion as I struggle with making my mind up.

I definitely do NOT want a high ram or a cut hood lol, the trinity more or less shifts everything higher rpm which would do better with that cam. BTR sells it as “max effort”, so I’m presuming it’s going to see a good amount of torque loss through the middle. Longer rod motors seem to make up for this while being near square shouldn’t hamper overall rpm windows.

i plan to keep the car on 93 either way. If had to guess it’ll end up landing blown still. The car had perfect manners and made great power, I just think n/a puts it down easier when you don’t want to run a radial and all that. I’ve so much other stuff that I thought maybe the Vette could be a bit wilder.

I didn’t start the journey to have the car NA; if it did there’s no way I wasn’t looking for something over 400 cui or trying to destroke an LS7.

I 100% want a ride though!

 

The gated stuff is a fun idea. Played with that on a friends car before. This will never be turboed though. I’ve been down that road and it’s not for me.

i think my weight argument is more balance related than parasitic. Having a lot of seat time in track focused and forced induction Miatas have screwed with my head.

 

Re trinity... I am setting one up for my 427. I got it because it was the far more affordable option at the time for the car I am not putting money into. For a 6500 redline it is a mismatch in my case, yet it starts to wake up around 5500 and keeps my soft top end from going flat.

Ol Mr Tooley apparently tuned the intake pulses and big plenum such that the thing lags and chokes for flow under that rpm but it seems to smooth out and shine as it climbs with those short runners. I have not modeled it into the 7500 range but am positive it leads the field where the msds and fasts nose dive. Too bad it isn't nylon is my only thought for sake of heat soak and retention.

 

The FAST 102 LSXr stuff seems to be the king for mid range power and anything staying under 7k or so. You REALLY need forced induction or high rpm to make use of the trinity. I agree that a composite option would’ve been nice.

FWIW this is just a fun street car and intend it to stay that way. I don’t want to make confusion as if it’s for competition use or constantly 1320’d on a trailer. For constant open track I’d want far less aggression in the cam for longevity.

 

I'm on the opposite side of sane trying to neuter a low cr 427 with high flow heads and time it so it's snappy. And yet the voice remains in my head to sell the Trinity and swap out for the 102 and grab an instant 20+ wheel under the curve. It's hard to break habits. But I'm trying to have the "send it all day and don't think about it" thing in this car to have a different experience vs the nasty boosted monster.