Guys,

I'm feeling the itch. I'm going to be buying an M6 LS1 Z28 soon. I want to explore a really nice NA setup. My goal is to run 122-125 mph trap speeds in full street form. I think I'll need at least 440 rwhp to be happy...and I want to produce it in an "overachiever" fashion..on the stock displacement..no nitrous..no forced induction.

This will need to be through catalytic converters, as well. This is asking a lot..maybe it's not feasible..please tell me.

Will this do the trick?

Stage 2 GTP LS6 heads
TR "Reverse Split" Cam 230/224 111 LSA
Long Tube Headers w/cats
LS6 Intake Manifold
Lid, etc., etc.

Is that enough cam? I could go to a solid roller..but I need to run with cats. Should I go with CarTek stuff?

Thanks.

 

u might be able to achive that...but to run 122 traps u could have less hp then 440...you would just have to lose a lot of weight of your car...have u thought about weight reduction....


or u can get stroked and do those mods and you will defintly beat 440rwhp

just my 2 cents

 

Thanls for commenting.

The objective is to have a daily-driver, reliable, street car. The car won't be heavy..I'm going to buy a base Z28 without T-tops, etc. None of that fancy "I look faster than I am" crap..and I'm not going to gut the car out and strip things off..rear seats, power accessories, etc.

Can anyone tell me what kind of power I would make from the setup I have in mind? I want to try this on the stock displacement.

 

G5X-2 H/C. 460 RWHP NA. Head over to LS1tech.com and do a search for 'G5X'. Plenty of info will come up.

 

why not supercharge? i dont get why you woudlnt..

 

Dyno #s don't mean **** till you take it to the track.

I'd also suggest the G5X2 cam, you'll really learn alot more by posting on Ls1Tech than you ever will here.

 

Why do you want the cats? I assume OK has emissions?

The cats will be a stifling (bottleneck) factor. And, likely any H/C set up to get 440 rwhp will be tough to do while meeting emissions (but not impossible). I guess I'm looking to know more about your situation first.

 

Thanks for the replies, guys. Let me handle this item by item...

1) Ahh...there we go. I was looking for the high-end #s people have been getting from H/C setups on stock displacement. Thanks for the tip. I don't drive a race car on the street..this car will be a daily-driver on the way to work car..and a car I will take on dates, etc. It can't be run with an open exhaust like these people have been running on the dyno. I'll have to take some power off of that.

2)If anything, I would go with a turbo kit. But the kits that are out now don't fit particularly well and require lots of tuning to run well (the LS1 motorsports kit is being delayed). And...an NA setup is reliable. A 10:1 compression engine can only take boost for so long before it lets go. Especially when you're making close to 500 rwhp. I would like to stay away from surprises.

I want something unique..an overachiever..I would love to run with or beat a blown car or a nitrous car with an NA setup on the stock displacement. I actually think that an NA setup is superior to a blown setup producing the same peak HP. With 440 rwhp NA, I would even feel confident running against a 490 rwhp blown car. The blower kits add weight, too. Overall, I'm unimpressed with the blower kits. I don't like the power curve (area under the curve, appears peaky), and there appear to be belt-slipping issues when you try to upgrade to a higher boost level.

Maybe I don't know enough..but a guy in Oklahoma only went 117 mph on 450 or 460 blown rwhp..that really turns me off.

3)I agree..what matters is what happens when you run it. This won't be a track car..but I will take it out to see what it will do. I've always been able to get my cars to run like hell..I think running mid-120s with ~440 rwhp would be pretty efficient.

4)Oh, let me clarify. My location is listed as Norman, OK, but I'm actually in Dallas. This means that I am going to be subject to the OBD-II computer check..and most likely a visual inspection for cats. So, in all likelyhood, I will need to have cats on the car. But that is not the only reason I want to have cats on the car. I've had cars with deleted cats before..my brother has a H/C LT1 with longtubes and no cats..it's too damn loud, and it smells like gasoline. For once, I want a relatively quiet, fast car. This is a daily-driver. I'm going to go out to eat with my co-workers in this car. I live in a quiet apartment complex. This can't be obnoxious sounding or smelling..and that's what you get without cats. This is also why I'm thinking of going with a Corsa exhaust. It's a trade-off, I know.

 

I recommend the G5X2 also with Stage 2 LS6 Absolute Speed heads. ASP pulley, Holley port matched intake, and about every other bolt on you can find.

Remember if you get a super quiet head/ cam car the valvetrain will sound very loud compared to the quiet exhaust. Your car will sound like a POS to dates, co-workers due to all the chatter under the hood..etc

Nitrous is what you need. (I know you don't want it though).

 

As far as H/C being superior, not true. There's alot more experience out there with H/C, so they're tuned easier. Second, as far as a power curve, you'll get a HELLUVA better curve with a S/C or T/C. H/C might PEAK high, but that's only cuz you have to rev the hell outta them, damn near 7K in most cases. In a blower car you're hitting your peak at 6K, so it's far more streetable. As far as belt slippage, you're only wanting 440rwhp, and belts don't go flying until above 550rwhp. So yeah, bottom line, nothing's superior, it just depends what you want. I'm not saying "go S/C", because you have a goal to beat FI cars with NA which is a good goal, it can happen. But just know what you're saying before you say it.

Nate

 

Well, I think I knew what I was saying when I said it. I made sure to qualify everything to defend against insulting people...I said I think that an NA setup is superior to a blown setup producing the same peak HP and that I don't like the power curve because it appears peaky. I purposely framed it as opinion instead of fact. And I'm here to learn..so I can't always know what I'm saying before I say it.

I have been looking at things for a while, but I could be wrong. Could you please elaborate a little more about the better curve with a superchager? I don't disagree about the turbocharger producing a better curve..I only commented on the NA curve versus the blower curve.

I don't consider taking the engine to 6800 rpm revving the hell out of it as opposed to shifting it at 6200 or 6300 with a blower. Again, I obviously haven't looked at this enough, but I really like the torque and horsepower curves of heads/cam LS1 engines. I think an NA setup provides a broad range of usable power up top..it doesn't deliver it in a peaky fashion. It seems that the blower setup doesn't reach peak boost until close to redline (6000 rpm)...and varying boost pressure would produce peaky power, wouldn't it? I need to look at some dyno graphs of the two setups at the same peak hp level.

Detroit: Good point about the valvetrain noise. I didn't think about that..probably because I've never had a H/C car with a quiet exhaust. I definately have some thinking to do. The exhaust won't be totally quiet..it might be a slight rumble, enough to offset the valvetrain noise. A quiet, understated lope and hum would be nice.

 

Centrifugal superchargers have a ver similar dyno curve to a NA one...

THe advantage of the SC is that you can still pass emissions easiers since you do not need overlap... Overlap kills emissions...

Centrifugal SC's are progressive... and yes you get max boost at max rpm but there is no lag... As in a NA most of the time you get max power at max rpm, hence you set the rev limit...

To tune is a lot easier a NA since the PCM sees everything as it is intended... Theese PCM's are not programmed or designed to "see" boost. So you have to use other methods of tunning or providing fuel as.. FMUs, additional injectors via superfueler or bigger injectors and adding "blindly" with the PCM...

 

True true true. And as far as the powerband, with a S/C it's pretty much a stock powerband on steroids. And like I said before, with a H/C setup, peak HP is usually on a pretty steep slope, they don't TEND to have a flat curve. And as far as you setting your post up as an opinion, I didn't see that...my bad. But I was just.... "educating" you then

Nate

 

hmm

well, I suppose then that a prime objective of a cam grinder is to find a profile that doesn't produce peaky power..a heads/cam combination that produces a flatter power curve..that's what separates the better setups from the rest.

I still haven't seen an efficient ET/trap speed from a blown setup..it seems that most people only list dyno #s in their sigs. A 460 rwhp M6 f-body should run mid-low 11s at 124ish. Are those the kind of traps people are getting?

 

Typically yes. But you have to realize when you talk about 460rwhp, with a H/C setup, that setup is pretty much maxed out, you're not going too much higher than that. Now, with a S/C setup, sky's the limit. So if you want to talk best of H/C (460 works) to the best, no, we'll just say, "really good" S/C setup of at least 550, that's about the limit before you have to rebuild the bottom end. Can you really compare the two? I don't know, I might be getting ahead of myself... anyway, as far as a S/C setup with 460rwhp, they'll be running about the same MPH, maybe even a little less, just depends on the H/C setup. It's all about torque. That's why Turbo's run insane MPH--- all that torque. So if you have a H/C setup that's stroked (most in the 460 range are) Then you've typically got more torque than a S/C setup of equal HP. Because remember, a S/C will multiply HP & TQ all throughout the powerband, so it's gonna stay pretty damn proportional. I don't know if you're going to understand all this but I tried

Nate