Guardsman

MODS - I know this is a V6 question, but there are a lot more people doing cam work on V8s than there are on V6s, hence, bigger knowledge base on cams in general. So, could you please bear with me, and not lock or move this? Many thanks.

I'm going to either build a new engine, or do a heads/cam/intake on my 3.8 in the future. The car is my daily driver (commute 1100 miles week with it), and I'm planning on keeping it, and swapping motors, parts, etc., until the body fails, or it becomes financially unfeasible.

Anyhow, since I use the car as my commuter, I'm not going to be doing any boosting or nitrous, but I want to squeeze whatever power out of this motor that is practical, and from what I've been finding, there's definately a few ponies still available from this thing.

Of course, the cam is one thing that is going to change. According to the info that I can dig up, my stock cam specs are as follows:

Intake duration: 182* Exhaust duration: 190*

Intake lift: .258" Exhaust lift: .255" (Assumed it is at .050")

Lobe separation: 115* Intake Centerline: 111*

Rockers are 1.6, so net lifts are .413 intake and .408 exhaust.


Here's the specs on the cam I'm thinking about:

Intake duration: 195* Exhaust duration: 201*

Intake Lift: .263" Exhaust lift: .273"

Lobe separation: 109* Intake centerline: 111.5*

With the 1.6 rockers, net lifts are .421" intake and .437" exhaust.

I'm also debating on whether I would be benefited by going with a faster opening and slower closing grind, or is that something that would only show results at high rpm?

I'll be getting the heads worked on, just a basic three angle job, and clean up the runners (casting flash, etc.), I'm not hogging them out, but I'm going to get them as close to matched as possible. Stock diameter valves (1.8" intake, 1.52" exhaust). All the valvetrain components will be new. According to what I found, the valvetrain is based on the SB2, so it already has lightweight components.

I'm retaining stock redline (6000 rpm), and either stock compression (9.4), or maybe 9.5.

Thoughts, comments, etc, on this? Thanks.

Oh yeah, and does anybody have engine modelling software that this could be run on? Thanks.

Old SStroker

Thoughts:

I assume you plan to improve the exhaust with at least a cat-back.

I wouldn't spring for a custom cam, but rather use what's available. I couldn't find the one you chose, but Comp grind 246 HR10 is somewhat similar:

192/200 @ .050 on a 110 degree LSA. Lifts are .480/.496 with the stock 1.66 rockers.

Comp describes it as "NA, daily usage. Significant improvement over stock. Must replace valve springs."

These lobes, 3103 and 3105, are more aggressive, with .300 and .310 lobe lift, and about the same duration. With the slightly increased LSA, and slightly shorter duration, idle quality should be better. The extra lift, which is equivalent to changing from 1.66 to 1.9 rockers on the cam you mentioned, should help a lot.

Yes, we have some decent software to model this engine. Data like head flow numbers, runner lengths, etc would be necessary to get reasonable answers. You might find this on some of the 3800 forums. I believe the supercharged guys have a couple of active forums.

PM me any data you can find, and I'll discuss it with Bret (Bauer Racing).

This sounds like an interesting project, and not too costly.

Guardsman

Yes, I'll be putting on a cat-back pretty soon, 2.75" at the outlet of the cat(using a WS6 I-pipe and over the axle pipes to make a new s-pipe, a chambered muffler with a 2.75" inlet and 3" outlet, and a loudmouth from there).

I can probably get a cam ground to those specs for less than $100, plus the sample cam and a blank.

The new cam specs are actually from the 3.4l V6 that was in the 93-95 Camaros. I was looking at the specs one day, and noticed that it's not too different from the 3.8 cam, but still a noticeable improvement. I'd just have to have a 3.8 cam reground, because the 3.4 is a 60* engine, and the 3.8 is a 90* engine.

Hard info on this engine is difficult to come by, though. My heads are the same as the NA Grand Prixs, not sure about the supercharged ones (they have the injectors mounted in the heads, instead of the lower manifold, like the NA motors, so I don't know if anything else changed).

Other than that, though, the Camaros use a unique manifold design. Our is a cast aluminum one, the front wheel drive cars use a composite one similar in design to the LS1s. According to GM, it's based on the SB2 intake manifold, so it's a spider-type, and relatively short runners.

The lifts your showing are a little higher than I'd like to go, but that would probably work good for the guys wanting to go full-race (relatively speaking )with theirs . I'm just looking for something that will allow the engine to breathe better, and work in the same rpm ranges that mine does now. It already likes higher rpms better, and alot of the cams that are available for the 3.8s are all high-end power.

Like I said, I commute with mine, so I don't want to slaughter the gas mileage too much. I'm actually hoping to find something with a bit more torque, in the hopes that it will help a bit with the mileage, by allowing a little throttle to get up hills, etc.

I'll e-mail you if I can find anything good, though. Thanks.

Old SStroker

You haven't considered adapting the supercharger from the transverse 3800 have you? I've thought about this before. Get a complete SC engine and wiring from one that "ran over it's crank". It's a demand system with the recirculating intake air at small throttle openings, so you'd only have the power when you wanted it.

I can't believe folks haven't tried this in Camaros. Search the web.

do0dfromcali

I know that a 110 LSA in a 8 clyinder is hard to get to idle correctly, but is it the same with a 6 clyinder? Or since there is 2 less clyinders, the 110 LSA is easier to get to idle?

Scalpel

iTrader: (4)

That's a sweet idea.

v8maro

iTrader: (4)

Cool idea but it costs waaaay too much to do, check out www.camarov6.com under forced induction, they are working on turbo's and SC's that are made for the rwd 3.8L.

-Steve

Scalpel

iTrader: (4)

Yea, IMO, it's better to do the LS1 swap into a V6 bird.

SStrokerAce

iTrader: (2)

The bad thing about the 3800 blower is that for the RWD setups the intake end of the blower would be at the cowel, that's kind of a pain in the ***.


Bret

Guardsman

Yeah, the L67 supercharger would be a major PITA to fit under the cowl, let alone work on. Holden uses that set-up on their RWD cars, and the TB is on the back of the engine. With that set-up in an F-Body, you'd have to pull the motor to work on the TB, if you could even get it to fit.

The 109* lobe separation is used on the cam from the 3.4l V6 in the 93-95 Camaros, and it doesn't idle bad at all.

Realistically, you'd be better off swapping an LS1 rather than installing an sc, because the sc alone is going to run $4500, and you could do an LS1 swap for that much, and it would be a lot easier to tune.

Also, the 99+ V6 Camaros use the electronic throttle control, so if you were going to put the M90 in it, you'd have to convert the accelerator pedal to a cable set-up, and use a different PCM.

For my car, I drive it 220+ miles a day, so I want to stick to relatively mild upgrades, something that will make some more power, without sucking down tons of gas.

As it is, the issue for the time being is the timing. I got Ease, and have been running that on the car. Whoever did the timing programming on the 3.8s needs to be drop-kicked, because they killed the ability of this engine to make power, and killed the fuel economy of it at the same time.

Whenever the throttle position gets near 30%, the PCM starts pulling the timing back 10-15 degrees. It's not just a tip-in retard, it stays back. The leaner the LT Trims are, the sooner the PCM starts pulling the timing back.

At 25% throttle and less, I can get up to 42 degrees of advance. Anything over 30%, and the advance falls under 30 degrees, usually between 18 and 25 degrees. At WOT, I haven't seen more than 20 degrees of advance.

Power enrichment doesn't kick in until around 80 or 85%. Also, at WOT, the PCM limits the injector pw, it normally stops right around 18ms, I've seen it hit 20ms once or twice.

So, I need to figure out how to reprogram the timing on this thing, and pull the limits on the injector pw.

One thing I'm going to to do is put a 180* thermostat in, and see if the PCM will keep more advance if the engine is cooler. Right now, I'm running between 190* and 195* on the freeway. So, I'll findout if engine temp is factor in timing control.

Once I can get the A/C line on the back of the compressor changed, I'm going to install 2000+ exhaust manifolds. The 96-99 3.8s use a rams-horn style manifold, the 2000+ use a tubular type like on the LS1s. Once I get that done, I'm doing a full cat-back exhaust, including the s-pipe (the s-pipe on the V6s is part of the cat, so that normally doesn't get changed with a cat back).

When I get a chance, I'm going to install 24lb injectors, and see if that helps out on the top end.

I've also got a TB and upper and lower intake manifold on the way, so I'm going to look at those, and see if I can do anything to make those flow better. Also going to look at temperature control for the upper intake manifold. It's cast aluminum, and the thermostat is mounted in it, so it gets up to engine temps, which can't be helping anything.

Argh.

Old SStroker

OK, I'm getting a little confused as to your goals. With an 1100 mile weekly commute, most of your driving is highway cruising, right?

You said you wanted to retain the 9.4/9.5 CR. Is that to use 87 octane? If 91-93 is in your budget, additional CR will help all phases of operation, if you get the tuning right.

IMO, bigger injectors will probably hurt more than help.

When is it you want/need more power? Do you run folks from stop lights regularly? Is it just the occasional race, or are you WOT uphills during your commute?

What I'm getting at is probably ovbious. If you just need a burst of power occasionally, say 50 more, reconsider nitrous.

v8maro

iTrader: (4)

The 3.8L's don't have the ability to tune like our ls1 edit or pred. As far as I know (from a few mo ago when I still had the v6) someone was working on it but it still wasnt out.
-Steve

Guardsman

Old SStroker, yes, this is my commuter, but it is also my play car on the weekends. So, I want this thing to be able to get up and go when necessary, but also be able to get decent gas mileage when I need it to.

As it stands, this engine has the capability to make significantly more power than it is, and that's what I want to get out of it. I'd be happy with 250hp at the flywheel, that'd be enough to wake this thing up, and make it competitive with other cars.

I just don't want to do nitrous, I'd rather make what I can without power adders.

The injectors that are in it now are only good for about 215hp, and I'm just about there now. Also, with the PCM limiting the pw to 18ms, I'm not getting anywhere near the fuel that I need to make power at the top end, I can see it from the diagnostics, and I can feel it. The car just doesn't pull anymore after about 4k rpm.

From what other V6 guys have said from their experiences, the PCM can handle 24lb injectors without killing the idle and needing tuning. So, I'm thinking those might help out with the top end.

So, to put it all together, I'm hoping that by going with the cams specs that I've listed, and the slightly larger injectors, I can still be able to get decent mileage, while at the same time, be able to make this thing move better when I open it up. Kind of the best of both worlds.

I'm stuck with the V6 for insurance reasons (a Z28 will double my insurance, which is already $1500 a year because of the number of miles I drive), so I'm trying to make due with what I have.

As for gas, no way that I run 87, this thing would be even more of a pig. As it is, I run a mix of 1.5 gallons of 76 100 octane, 3 gallons of 91 octane, and the rest 89 octane. I get a noticeable increase in the power with that mix. I may bump the CR up to 9.5:1, but a guy I work with who races, was saying it probably wouldn't do much good to raise the CR much because I have iron heads, so I'd start running into detonation problems. As it is, I get a little detonation sporadically above 4K at WOT, or when the engine starts lugging, i.e., going uphill.

Magnus

iTrader: (4)

Definately check out firebirdv6.com, there is a ton of cam info there and many members have aftermarket cams and can give you real life experience and advice.

My advice to you (I'm a former cammed V6 owner) is go with something bigger. That dinky cam will give you very little power in the end. The v6's dont gain like the V8's do from cams. Smaller engine, smaller HP increase.

I'd recomend a 206/206 with .506/.506 valve lift on a 112LS. It will have a little bit of chop to it but won't be undriveable. If you want less chop you can just go with 114LS... but realistically, anything under 206 duration will probably not be worth the cam swap.

Old SStroker

I'm still confused (sometimes that's a short trip for me. ) You have stock 9.4:1 compression, designed for 87 octane gas, you said you checked that timing is heavily retarded @ WOT and need home-brewed 100/91/89 gas to prevent detonation? Something ain't right in the chicken house, IMO.

Is this the 200hp @5200 Series II 3800? If it's not, how about buying one from a salvage yard from a 2002 or so and swap it in. They aren't that expensive.

If it were my engine, I'd do the valve job, maybe just clean up the ports for a few cfm, shave the heads for about 10:1, put the good exhaust system on it, drop in the Comp HR and springs, find someone who can tune it, and run 91 octane. I believe cruise economy won't suffer, and may improve with the higher CR and freer breathing. It's also hard for me to believe that the stock injectors can only support 7.5% more hp than the stock 200.

I would respectfully suggest not trying to reinvent the wheel; just do the normal things that work. If you don't get more oxygen in and out, you're not going to get those extra ponies.

Good luck!

My $.02.