turabo87

Hi folks,

I'm saving up and planning for an NA street build next year to wake up the Vette. Currently stock 1999 LS1 with a Magnaflow Catback. Scenario A for mods I want are a cold air intake (SLP Blackwing or K&N style), 1-7/8" catless Long Tube headers (Speed Engineering or bargain used long tubes), Brian Tooley LS1 Stage 3 Cam (or similar TSP grind) and Supporting Cam Package, and a rolling dyno tune. Scenario B is same as A but with additional mods; getting an LS6 or Dorman LS6 intake manifold and/or maybe swapping the cylinder heads to used LS6 heads or having my current LS1 heads ported. Reasons for the BTR Stage 3 is sound and driveability (don't want to lose midrange torque and streetability) and I'm open to changes.

My goals is just to have a liveable daily NA build with a semi-rough idle, and push somewhere north of 400whp, and be cost-efficient in the process. Just want to learn from others so I can budget wisely for it, and know where and where not to skimp. Also, I'd like to know what Scenario A and Scenario B could possibly land me in whp. Also, I'm not planning on any other engine supporting mods unless it comes highly recommended to do so as preventative measures. I'd like to keep my budget between $3-4k if possible. Thanks.

FYI: Mine is a 1999 FRC 6speed manual with 3.42 gears and Z51 package, with C6 Grandsport wheels and on 89k miles on the odo.

RockyMtC5

turabo87

What were your mods? Was this with labor? Let me clarify that my budget is parts budget and dyno; I plan to do all the labor of the parts removal and installation myself since I have access to a shop and tools.

RockyMtC5

RockyMtC5

turabo87

So, let me get this straight, you were still able to get to 430rwhp without swapping or porting the heads? You kept the stock LS1 head castings? That would be awesome news because I was planning to get all the parts and do all the work on a couple of days with the Vette in my brother's shop. Didn't want to take the heads out for porting due to the lead times and the Vette will be down too long while I wait on heads, and new heads are just too much cost for me, and used LS6 heads well there's always a risk with that.

PS: I would consider your FAST 90/90 setup if price is right for added airflow. What would it include?

RockyMtC5

Time for a C-5

You can get to 400 pretty easy. Not sure how livable/daily friendly a BTR3 cam is...that's subjective. It's a good size cam. I got there with a much smaller/friendlier 222/226 cam but with ported 243s. Definitely upgrade your LS1 intake. There's a lot of "while you're in there" parts like the oil pump, timing chain, balancer, lifters and trays, rocker trunnions, and obviously the valve springs and pushrods. Once you're done you'll make good power to close to 7k rpm but you're clutch hydraulics won't want to shift properly over 6k rpm, so keep that in mind.

If i had to do it all over again I would give serious thought to a supercharger. I'm thinking about it now and obviously rockymtc5 too. You would still want to do the exhaust and shore up the valve train (springs, pushrods, trunnion kit) but it would be just as streetable as it is today with a lot more power and a little more cost.

turabo87

You were spot on all along. I finally finished my build and tune. Stayed with the 853 heads, but went with all other supporting boltons including offroad long tubes, LS6 intake and cold air intake. I ended up with a mild cam (.585/.585/228/230). Made 397rwhp/397rwtq. My full results post is here https://www.corvetteforum.com/forums...n-results.html

Kingtal0n

Good, Lift is below .600
If you want the engine to last, use less than .600 lift (.585 is about as high as I would go)
And use the 'weakest' spring for that lift, usually PAC1218 is used with that cam (sloppy stage-2 from Jegs is like $250 or less) The whole cam+springs job can be done for $360

edit: Info added;
https://sites.google.com/site/sloppy...sloppy-stage-2

How does it sound at 6L?
That guy made 1000 RWHP on a dynojet with that cam, PAC1218 springs, in a stock 6L motor (turbo). Then it went 9's off a footbrake stall.

turabo87

Yea, that's my cam, the Sloppy Mechanics Stage II. I got it from JEGS. I know I could've gone with single PAC springs and put less strain on the valvetrain, but I went the Scoggin Dickie dual valvesprings for some extra insurance. All my other valvetrain components were beefed up anyways (new BTR hardened 5/16" pushrods and new LS7 lifters and trays, and upgraded rocker arms with trunnion upgrade.) I don't know where you got your $360 cost from though lol. I think you missed an extra 0. I did the whole job myself, including the heads removal and spring replacement, cleaning valves...etc. Lot of extra crap too such as replacing oil pump and timing chain, the LS6 intake floor modification, changing my exhaust manifolds for long tube headers and offroad x pipe...etc. The whole cam job and cylinder head job is closer to $3000 job laborwise if you ask me, but I saved myself all the labor.

Kingtal0n

most people just do the cam/springs and go because they are doing it to a $400 engine (4.8/5.3/6.0) and don't want to risk anymore than that.
Heavier springs don't add insurance unless it actually requires them (insane ramps or very high rpm with solid lifters)
Heavier than necessary will add valvetrain wear and tear, reduce total mileage and increase the probability of having catastrophic failure.

Time for a C-5

I thought I was the only person on this forum running a single spring.

turabo87

Kingtal0n

The less pressure, the less stress, the better for everything. That goes for all mechanical systems, fuel pressure, blood pressure, air pressure, fluid pressure of any kind, and mechanical force in general.
Engines using PAC1218 will do 1000rwhp and go 50,000-100,000 miles.
There is no reason an engine with half the power needs something stiffer.
It just means more stress. Even at idle that cam has to push the lifter up and force that spring open... over and over and over. Even just to crank the motor everything will be under more stress with the stiffer spring.
I've seen failures due to high spring pressures across a slew of platforms, 4-cylinder 6-cylinder and 8 all do the same thing. The valve drops and the engine turns to trash.
If someone actually needed the high pressure spring for some kind of racing abuse its a necessity. But daily driven cars that sit at idle in traffic and go long distances on the highway are NOT suitable candidates for serious springs.

Kingtal0n

The extra spring is a great idea. Just not the extra pressure. It will probably be fine, I tend to be over dramatic and assume the worst case scenario.
But surely you realize that with the extra pressure comes additional wear (you seem to understand that) just make the next leap and realize that additional wear occurs everywhere, including the guide, as the valve may wiggle side to side after so much bronze wear and escape the lock at high rpm (during an improper rev-limiter event is common), regardless of whether the springs themselves fail or not. In other words I don't think the springs breaking is the concern, its more likely wear and tear gradually loosens everything up and that is what causes the failure. In all the 4 and 6 cylinder motors that dropped valves with high spring pressure I've never seen the spring break as the cause.

turabo87

Interesting about the failures. I happen to agree with you, it's just mechanical common sense on any mechanical system, but I just I think it was a little over dramatic like you said, but yes I agree with you there is additional wear. But just for fun, I wanted to quantify and lay out the facts about the SD7650 dual springs I have versus the PAC1218 in my actual application. Here's the facts:

SD7650:
k = 392lb/in
closed pressure = 160lbs@1.800"
actual max open pressure @ 0.585" lift (my application) = 229lbs + 160lbs = 389lbs.

PAC1218:
k = 313lb/in
closed pressure = 130lbs@1.800"
actual max open pressure @ 0.585" lift (my application) = 183lbs + 130lbs = 313lbs.

Will that extra 76 lbs at max lift cause me issues long term? I doubt it but undeniably I will see more wear long term. How much? Difficult to say. I'm still pretty happy with my decision and at .585 lift I'm not that concerned.

PS: That's some clean squat form, good job.

Kingtal0n

thanks for posting the info for the springs!

Its more that I just want the info 'out there' because people tend to buy things that other people buy without really knowing why or what they are getting.
So I always emphasize "use the weakest spring for the application /etc" in any related thread just as a public announcement/service to educate

It wasn't directed at you or the specific springs you choose. You obviously knew what you are getting.

When the search comes up for others though, they will see the info and it becomes more of a choice, rather than just a blind purchase. Or at least lead them to investigate further about something which they may have never considered.

---
Squat bench dead- not sure I could live without it now. The flexibility and strength is a modification to the body, which is really a vehicle.
So we modify our vehicles through diet, training, get good sleep. Wake up, go outside and modify our other vehicles to make them faster as well ;D

turabo87

Good philosophy brother. That's my next project build, my body. Gotta get back at it and get lean again. Seems the more I invest in the vette, the fatter and more out of shape I've become. Time to change that around and get lean again. I see you're at Miami too. Maybe I'll see you around. If you see (or hear) a cammed, black C5 FRC out there, it might be me.

Kingtal0n

Interesting video I just saw thought I would pass on

Good example of a valve drop without spring failure
also innovative = junk ;D