JakeRobb

UPDATE: the plans and questions here are out of date. Jump to post #29!

First, PFA:


I have a 2002 Z28 M6. The engine is all stock; power mods currently include a lid, a Corsa catback, and a 15lb forged steel ACT flywheel (paired with a McLeod RST twin-disc clutch). I have also done a bunch of brake and suspension work which isn't really relevant to this conversation.

It made 325rwhp on a Dynojet before I did the clutch and flywheel. I don't actually care about power numbers, but they're a good point of reference. Torque peaked at 4400, power at 5200 -- just like the specs say. The point being, it's a normal, healthy, stock LS1.


I live in Michigan and DD the car whenever there's no salt on the roads and it's warm enough for summer tires. Whenever I get the chance (about once a year, currently pushing for twice), I do an HPDE. I have been to three HPDEs so far, and I've been improving a lot. I measure my lap times and make videos.

As you can see in the above video, I have an axle hop issue under braking. (I just skimmed through and found one example of it at 12:22 as I brake after cresting the hill.) In addition to upsetting the car, the violent shaking has been breaking parts. First, it ripped the exhaust hanger off the pipe, leaving the exhaust to sit on and rattle against the panhard brace.


So, I had a friend with a welder pop the hanger back on, and I was back in business. Then, during my last session of my most recent HPDE, that very issue sent me into the gravel pit outside T1 at Grattan Raceway.

When I restarted the car, I discovered that the exhaust was broken again. This time, it was the Y-pipe right at the header flange.


Now, I have a strict policy of not replacing broken factory parts with more factory parts when there's an obvious upgrade available. I also have a policy of not buying low-quality parts. That means it's header time!

Here's where the snowball builds:
If I'm doing headers, that means a tune.
If I'm paying for a tune, I want to maximize the value of my money and time, so I'm going to do whatever other power mods might make sense.
Since it's a 4th gen, and **** is hard to reach in general, that means I'm taking this opportunity to replace the factory-original spark plugs (car has ~120k miles on it).
Since I spend time on a road course, I want to put due consideration in on any opportunity to improve reliability and cooling.
Since I like going fast, I want to consider opportunities for more power (but since it's a DD, I don't want to do much that hurts drivability) and less weight.

That all culminated in a call to Sam Strano, who hooked me up with this pile of goodies:


The pile includes:
Kooks LTs and catted Y
Magnecor plug wires and NGK iridium plugs
UMI road-race K-member
UMI adjustable LCAs (hoping it helps the axle hop)
Strano swaybars (replacing the BMRs I have on now; the BMRs make the car too tail-happy on a road course, and Strano says this will help.)
Full set of Moog bushings for the front suspension

So, the plan is:
1. Lift car off front cradle.
2. Remove engine from factory K-member, put on engine stand.
3. While on the stand, do unspecified things to engine (see below).
4. Move things over from factory K.
5. Put engine back on.
6. Put car back on the front cradle and button it all back up.


Thanks for sticking with me so far! Here's where we come to the part where I need your help.

I want to do a cam and valvetrain, plus everything I need to support those updates and keep it super-reliable. The goal for the cam is to broaden the torque band, raise the power peak, increase the rev limit, maintain drivability at 1500rpm, and make minimal to no sacrifice in reliability. I don't want to have to tear the engine down again until I'm ready for more power.

With the engine as-is plus headers and tune, I'm expecting it'd be ~350rwhp. I think that there is a cam out there which will meet my criteria and get me in the 380-400rwhp ballpark. I'm not super interested in going higher than that right now.

I want to keep temps down as much as possible, so I am planning on wrapping the headers. Currently looking at Thermal Zero's Lava Wrap. Anyone know how much wrap I would need to cover down to the collectors? I can buy 2" wide wrap in lengths of 25', 50', and 100'.

Because road course, I am also considering:
Improved Racing oil pan baffle & windage tray
Some kind of oil cooler -- advice on this would be appreciated.

I'll definitely upgrade the rocker trunnions. I was considering going to Yella Terra rockers for the additional stability, but I've done a bunch of reading and I think that's a waste of time and money. Upgraded stock rockers will suffice until I can afford a full shaft-mount setup from someone like Jesel.

I'd appreciate your thoughts on:
Cam (and please don't just tell me to get a BTR3. Tell me why you think that fits my needs. I'm also interested in advice regarding cam manufacturers. Comp? Advanced Induction? Lunati? Cam Motion? If you have a cam that you think would fit, I'd appreciate sound clips and dyno graphs when available -- especially dyno graphs that include the lower RPM range!)
Valve springs (Beehive? Conical? Dual? Manufacturers to prefer / avoid?)
Pushrods (Reduced orifice to reduce oil pooling in the top end?)
Timing Set (LS2? Do I need to / should I replace the dampener? Should I bother with anything adjustable?)
Lifters (LS7? Should I get trays too, or are my current trays fine? I'm planning on drilling them to improve oil drainage.)

While I have everything apart, budget permitting, I also want to do:
Oil pump (Melling? Open to suggestions and advice here.)
ARP rod bolts (I've heard that you can distort the factory rods installing these. Is there any truth to that? If yes, is there an alternative, or a way to mitigate/eliminate the risk?)
ATI Superdamper
I'll probably use ARP bolts for a lot of things on reassembly.

I'm pretty sure I'll need to upgrade the injectors. From what I can tell based on some BSFC calculations, I think my stock injectors are already running at 80% duty cycle. I'm figuring on a set of 42# Bosch injectors.

Do I need to be thinking about the fuel pump?

What am I forgetting/omitting? What gaskets will I need to replace? Are any of the bolts I'll be removing torque-to-yield? Should I replace motor mounts with polyurethane?

BTW, I know that headers, plugs, cam, and K can all be done with the engine in the car, but I feel like since I'm doing all of them, I'll save myself a lot of trouble this way. I'll learn more about the car. And when I inevitably break off a header bolt, it'll be MUCH easier to get it out. The point of this thread is not to discuss that aspect of the approach; thanks.

Oh, and I know my 241 heads are a limiting factor. If I find myself wanting more power later, I'll grab a set of 243/799s, maybe get them ported, and be on my way.

Thanks in advance for any and all advice. Sorry for the long post -- I feel like it doesn't make sense to ask these questions without being thorough, since so much of it is inter-related.

JakeRobb

Some of my thoughts and findings based on research I've done so far:

• I really like what Advanced Induction has to say about cam manufacturing precision, but I get the impression that their portrayal of other manufacturers is out of date at best, and that I can pretty much count on any modern cam being within a degree of spec.
• I'm leaning towards conical valvesprings as the most modern choice for controlling valves without harmonics and with minimal weight. I'm also tempted by the idea that a dual spring has a backup that will keep you from dropping a valve in the event of a failure.
• Regarding cam advice, I know that the best move is to call the manufacturer and ask them to recommend something. I just want to be informed when I make that call, and I'm hoping to learn some things that help me decide who to call first.
  • I really like that for an extra $50, Cam Motion will sell me a cam made from a much stronger alloy. Seems like cheap insurance.

00pooterSS

iTrader: (40)

Poly motor mounts. It's the perfect time to do them and I loved them on my car. Engine was much more stable and didn't increase vibrations. The poly trans mount will cause a lot of vibrations, I would leave it rubber.

Heads. TFS as cast 220's or ported 243's would be my choice.
Intake Fast 92 or 102

Cam, summit stage 1 will make the power you are after easy, it's on the smaller side so you can run a single beehive. I've seen many single springs break without any valve damage. When the spring breaks the valve falls down a little, not all the way. This cam should give you a good broad power range and not be peaky, which is excellent for road racing. Also nice to the valve train, again great for road racing.

Replace all gaskets while you have the engine out. Get the sac city corvette cover alignment tools so you don't mis align a cover and cause a leak. Also get the sac city barbell and put it in while rear cover is off. Helps with steady oil pressure etc

I would put a new cam sensor in it or at least replace the o ring on the sensor. They leak and are a pain to get to in the car

That's all I got at this time. There's many cams that fit the bill. Summit LS cams are really nice and lower cost than all others, cost doesn't seem to be an issue here but it's still nice to save a buck and retain quality

Skip the ARP rod bolts and leave the rods alone. Keep the revs below 7k and you'll be golden. With the above cam going over 7k would be a waste

Absolutely get that windage tray and crank scraper

Grab a summit underdrive pulley too

Look into turn one power steering pump, should free up a little power and be road race friendly. may want to add a PS cooler while you're on this bunny trail

whatsa347

iTrader: (6)

Advanced Induction HCR 241's since you already have them, PSI valve springs, EPS 226/230-226/234 range, MGW shifter if you don't already have one, you seem to have done everything else really, clean car and money well spent honestly. Don't see too many F bodies out in HPDE's around here, nice to see one doing some work.

Jenson

iTrader: (32)

I'd definitely do baffles and crank scrapper and if the budget allows I would also look into an accusump for those HPDE days.

If you go with a summit cam, I'd do the 8706, 8707, or 8715 depending on how much lope you want. I'd personally run a 222/228 LxL lobe (great for RR applications) on a 111 since you arent worried about a ton of top end power. The conical springs are the best.

Get the biggest pushrods that will fit your heads.

I'd get a good PHB and a long T/A to help combat axle hop if you havent already. Seeing as how you talked to Sam I can only assume you've addressed those already though.

JakeRobb

I already have the Energy Suspension poly trans mount. I have swapped back and forth with the stock rubber a couple times just to make sure, and I don't notice any difference at all. Thanks; I'll get poly engine mounts too.

I'm leaving the heads and intake manifold stock for now. If I find myself unsatisfied with the new power level, those are next.

Do you know who cuts Summit's cams? I'm guessing Comp?

This seems like solid advice. Thank you! I haven't done this before, and I'd appreciate help putting together a list of the gaskets I'll encounter. Right now I'm planning on:
Valve covers
Timing cover
Intake manifold
Exhaust manifold (new gaskets came with the Kooks LTs)

I wasn't aware that I'd need to remove the rear cover, but it seems like it'd be trivial at this stage, and the barbell upgrade seems like worthwhile justification. I assume that needs a gasket too.

What else? I'm not going to remove the heads, so no head gaskets.

I was told to worry about the factory rod bolts if I was going to be in the upper 6xxx range frequently. I'd love to set a 7000-7200rpm fuel cutoff. Does that change your cam advice? Am I asking for too much to have a cam that doesn't suck at 1500rpm and is worthwhile at 7k?

The bolts are inexpensive and I'll already have the oil pan off. You really wouldn't do it? I like having things built to handle more than I'll ever throw at them.

For sure.

I'm planning on an ATI Superdamper, which AFAIK replaces the crank pulley. I am not aware of an underdrive version, but would consider it.

Already have a cooler that I forgot to mention is going in as part of this project. I definitely want to do the TurnOne pump, but it has to wait for budget reasons at this time.

You'd spend $1400 machining my stock castings rather than $350 on a set of 243s?

Thanks -- any particular reasons for those suggestions?

I have a Pro 5.0 shifter that I'm pretty happy with. I've heard good things about the MGW, but I don't remember it being an option back in 2009 when I put it in. I've had this car a long time!

There are a couple LT1 guys in my area that I see regularly, running much more highly modified cars -- 400+ci stroker engines, full cage, gutted interior, etc. But yeah, there aren't many of us.

I've thought about an accusump, but I feel like it's unnecessary weight and complexity since I'll have the pan baffles. Even with my stock pan, and having seen cornering forces in the 1.25G ballpark, I haven't had any oil starvation issues yet.

Thanks.

That's what I have heard. Confirmation is good.

Biggest diameter, right? For stiffness? Do you know what a 241 casting can accommodate? I'm planning on getting pushrods from Trend Performance.

I have a BMR panhard and a UMI adjustable tailshaft-mounted torque arm. Neither seems to have made any difference with the hop. I'm pretty sure the root cause of my problem was going to a six-piston brake caliper up front while leaving the rear stock -- changing the piston surface area threw off the proportioning, so the rears are getting too much pressure and locking up early. My plan first is to go more aggressive on the front pads and less aggressive on the rears to compensate. I'm also putting in the LCAs, which might help. If the problem persists, I'll probably get a 4-piston caliper setup for the rears.

00pooterSS

iTrader: (40)

Cool on the trans mount, oddly I didn't have the same experience. But thanks for the feedback I'll stop telling everyone to stop using them lol

Gotcha on heads and intake

Summit won't say who is cutting them but plenty of speculation has lead to believe it's a high end shop here in the US
I would private message summit. The tech guy on here is very knowledgeable and can easily help you with which cam to go with. Generally a milder cam is better for broad power like you're looking for. So their stage 1 or 2 would likely do the job well for you.

On the gaskets. Do the rear cover because they do seep if not leak over time. LS motors are great but as they age they really start leaking from everything. So go ahead and take care of the rear main plate gasket and rear main. While there get rid of the plastic barbell and put in the billet barbell. It has o rings and they do go bad over time so it's only a matter of time before your current barbell bypasses some oil if it isn't already. Do the oil pan gasket too, which obviously you will with the scraper etc. I haven't seen it mentioned but I imagine the barbell is tough to pull out, if so you could drill a small hole in it and put a self tapping screw in the hole and pull on the screw. I do that on broken off dipsticks etc here at the shop.

Even better on the ATI. I'm not a road race guy and I've never seen it mentioned but I wonder if an underdrive is helpful in road race since you're at upper rpm a lot, keeps accessories from turning high rpm the whole time and more in a mid rpm range...?

By the way Trick Flow as cast heads are phenomenal on an LS1 and are right around $1700, they also have thicker decks and better valve angles, things you wont get with a ported stock casting. Just throwing that out there as something to consider if you start considering heads.

G Atsma

Pooter- The billet barbell comes with a hole drilled and tapped for screw to thread in and yank it out. Cool huh?

00pooterSS

iTrader: (40)

That is cool, good idea if you ever have to pull it out. Too bad they didn't on the OEM one.

Che70velle

iTrader: (6)

Pooter, from what I’ve gathered, the poly mount deal is a combination issue. The poly trans mount is a no-go only if your already using the poly engine mounts as well. As long as your using the rubber (Oem type) engine mounts the poly trans mount is a non-issue, and vise-versa. It basically makes the engine-trans combo too stiff for the sub-frame cars...I guess?

00pooterSS

iTrader: (40)

Oh okay that clears it up a bit. Back in my F body days I had poly engine mounts with a rubber trans and many people commented on how my car was completely squeak and rattle free (i'm a squeak and rattle **** so I really stay on top of that stuff, it wasn't that my car was that special) but my cousin had a 99 SS when I had my 00. He had poly eng and trans mount and his car vibrated every interior panel like crazy and would vibrate your teeth. It was horrible.

I also have heard it's a terrible combo to use the poly trans with rubber engine mounts because way too much force is absorbed by the trans case by having a near solid mount and the engine twisting all over the place. Those F body OEM rubber mounts are about as stiff as jello. Heard a couple stories back in the day about cracked trans housings.

From my experience with them the poly engine mounts are wonderful on a F body. I used to build honda's too, I ran rubber mounts on those (they had 5 so they held fairly still) but I had buddies that had poly mounts and they were terrible, it's super close to a solid mount so you feel everything the engine does, but somehow it wasn't that way with the F body engine mounts (poly eng only)

JakeRobb

Thanks all! I wonder if I still have that stock trans mount somewhere. No worries if not; I can probably get one from RockAuto.

A couple of my questions remain unanswered; just summing them up here:

How much wrap do I need for headers? Anyone have a product suggestion other than ThermalZero's Lava wrap?
Any advice on oil coolers? I know the stacked-plate type is best; any thoughts on whose filter-adapter-thing to use, or how/where to mount the cooler?
What's the thickest pushrod that will fit in a stock 241?
Will I be good to go with an LS2 timing set and LS7 lifters?
Should I replace the oil pump?
Are 42# injectors the right call?
Will my stock fuel pump keep up?
Are any of the bolts I'll be removing torque-to-yield?

00pooterSS

iTrader: (40)

Run a OEM rear mount if possible. Or some sort of big brand name. In my experience as a tech there are two quality levels when it comes to stock replacement rubber mounts. OEM and trash.

I'd go with header coating over wrap personally. If I did anything at all. Scroll to the bottom of the thread
https://ls1tech.com/forums/generatio...ot-coated.html

I could help with the rest somewhat but there are others that know exact and better answers to each question you have, but I'll take a few of them.

-Head bolts are tq yield. And the crank bolt. All others are reusable. (forgot you're not pulling heads, I always re use the crank bolt but it's technically tq yield)
-Never a bad plan to update that old fuel pump (if it's old). The racetronix 255 with hotwire kit is really nice. If racetronix is still doing their thing that is, haven't looked them up in years.
-WS6store has some nice single chains with billet gears that aren't sky high in price, they also sell a ported LS6 oil pump, oil pump also never a bad idea when you're there considering how cheap they are, make sure do shim it etc to make it perfect, you can google that or youtube it
-42# should be plenty, if you plan to go e85 consider 60# to have headroom in the future
-Improved racing should be able to take care of your oil cooler needs and adapters (and yes stacked plate over tube and fin), I mounted mine in front of my ac condenser with some home made brackets that bolted to the cooler, then drilled the radiator core support at the bottom and screwed the bracket on there. I mounted in front of the a/c condenser in the air not strapped it to the condenser. Or you can mount it in the bumper with a fan on it. Or under the car. I'm sure some people will chime in with more ideas there.

JakeRobb

That was my original plan, but coating is so expensive!

As far as not doing anything, a primary goal here is to reduce underhood temps.

JakeRobb

RockAuto has the ACDelco mount for $52.79. Amazon and a variety of others do as well. Post-bankruptcy, a lot of "OEM" parts are made in china and are junk anyway, but the fact that it costs double the other options is encouraging.

I noticed that RockAuto lists the same part number (22174970) for both auto and manual. Can anyone confirm?

My plan is to wait until it's all put together and see how it is with poly everywhere. If I don't like it, I'll spend the $50. It's an easy swap....

JakeRobb

Pooter, is this the Racetronix hotwire kit you're referring to? https://www.racetronix.biz/customkit...p?kc=fpwk-017w

I think I'd be getting that as part of this: https://www.hawksmotorsports.com/fue...g-harness-kit/

I don't see much point in E85 for a naturally aspirated engine, so I think I'll stick with the 42#. I'm under the impression that it's harder to tune for drivability if your injectors are using a smaller percentage of their duty cycle.

00pooterSS

iTrader: (40)

I hear ya man on both of those items, as far as how much wrap to use I don't know hopefully someone chimes in on that.

I agree that most are probably chinese now and the double priced ac delco is encouraging. You may still check with a GM dealer, I found a few parts at the dealer back around 2012 or so that I figured would be long gone for F bodies, you never know and may be worth a shot. I got 2 of the last 3 factory SS rear bump stops left in the country when I was looking for them. Got them from the dealer.

That harness says it's for the updated connector. I have been swapping harness pigtails on new GM pump installs (for late 90's and early 00's vehicles) that come with the new pump. GM updated the fuel pump connector at the fuel tank to carry more current. An racetronix sells an updated bucket (the module the fuel pump sits in) that already has that connector.

This kit is for your car, comes with the right pump wiring and converters to reuse your bucket and have the updated wiring. Racetronix is the only company I know of that makes a pump and adapters to put a replacement fuel pump in the bucket in the OEM way and still use a venturi to keep the bucket full of fuel so the pump stays immersed in fuel and stays cool. Other upgrades people do (where they just slap a walboro 255 in) don't have that and they zip tie or hose clamp the pump to the inside of the bucket and drill holes in it then if your tank gets low you may go dry on fuel. The racetronix kit keeps the pump in fuel even if the tank is low that's why I went with them years back. Read all about it on their website. I haven't installed a racetronix kit in years but I believe this is the kit you want. But please call and confirm.
https://www.racetronix.biz/customkit...sp?kc=rfpk-001

I agree with you on the e85 and on the duty cycle, was just throwing things out just in case

Edit: the hawks kit is probably correct but the raetronix link I posted is a complete kit also, looks like it may have more components and is also $20 cheaper direct from racetronix. So check out both and give racetronix a call to make sure you get the best kit for you.

Majestic9C1

iTrader: (19)

I have both poly engine and trans mounts and I dont notice any increase in NVH much.. but different people notice different things

G Atsma

Truth is, the tranny mount is does not have too tough a job to do. If you have poly engine mounts, the brunt of most forces are handled. Then the tranny mount is mostly along for the ride.

Majestic9C1

iTrader: (19)

If you plan on doing more Autocross events you should invest in a watts link setup... I've had mine recently on the car for 2 weeks and the ride and handling is night and day and I wondered why I waited so long to get one. even DDing the car as you say you do would make it so much more enjoyable