• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Modding to 300 hp



Actually, i believe the LS4 makes peak torque earlier on than we do.

In any case, our stock heads flow pretty poorly. Try running a comparison on LS4 Heads vs L67/32 Heads.
 
Let's try to stay on topic okay :)
The example is a 300bhp L67 vs a stock LS4.

What we've been told is that the v8 has more "top end" because the L67 falls on it's face.
So I'm wondering, if we compare the two dyno sheets, will the LS4 have a clear advantage in the "top end"?
 
300 hp l67 to 300 ls4 my moneys on the l67 car all day every day unless for some magical reason the GXP was lighter...............
 
Nixon said:
Do you accept the challenge?
Click to expand...

I already accepted this challenge years ago. I just wanted to see what people would come up with when forced to explain themselves.

In short; A 300bhp ~250whp L67 with 1.9s has more low end, same mid range, and same top end as a stock LS4. They literally go step for step with each other. And of the dozens of dyno sheets I've looked at, when peak whp is the same or close to the same, the curves above ~4k are nearly identical. Under 4k, the L67 has a major advantage.

So actually because of the higher peak tq numbers of the L67, it will "feel" faster. Maybe that initial punch makes the top end seem less impressive?
 


The LS4 has a tiny cam and restrictive manfiolds. The heads are 243's, same as on the LS2 so I'm sure they flow pretty well but they're obviously not the choking point.

I just like to rib people when they say things like the L67 has no top end (in regard to power curve, gearing is a whoooooole nother' topic)

I could really send things into a frenzy by saying an L67 that makes the same peak whp as a stock LS1 has more top end than the stock LS1 ;)
 
Woa....what rockers are recommended for a mild build, 3.4, headers,pcm and cai. And what type of power are we talking? ....just when I said I wad done
 


Id take the challenge of going agents a GXP after my build :) so I'm hearing a lot of ppl for rockers. Is that just rockers and I'll be clOse to 300, or that and headers? I was planning headers next but if rockers give me more for my money might do that. Being a budget build I can only get one thing at a time. Also do rOckers help with riding knock?
 


SnowFlake said:
I already accepted this challenge years ago. I just wanted to see what people would come up with when forced to explain themselves.

In short; A 300bhp ~250whp L67 with 1.9s has more low end, same mid range, and same top end as a stock LS4. They literally go step for step with each other. And of the dozens of dyno sheets I've looked at, when peak whp is the same or close to the same, the curves above ~4k are nearly identical. Under 4k, the L67 has a major advantage.

So actually because of the higher peak tq numbers of the L67, it will "feel" faster. Maybe that initial punch makes the top end seem less impressive?
Click to expand...

You're making my point for me... I said that adding rockers would alleviate the dead top end of the 3800.

What we've been told is that the v8 has more "top end" because the L67 falls on it's face.
So I'm wondering, if we compare the two dyno sheets, will the LS4 have a clear advantage in the "top end"?
Click to expand...

300 is easy... it's over 300 where things start to get tough.
mike, what do u mean the v8 has more 'top end'? I was always confused about what people mean by that.
Click to expand...

But you need valvetrain mods to make 300bhp... even if it's just 1.9s, right?
Click to expand...

I'm still confused, is this a gearing thing or a power curve type thing?
Click to expand...


So what you guys are saying is that if we compared a mild bolt on gp with 1.9s that makes the same whp as a stock LS4 that the LS4 will make it's peak tq and peak hp higher in the RPM range relative to the L67 and it will carry decisively more power into the redline?

Am I on the right track?
Click to expand...

Why do you ask all your questions as if you're setting someone up to tell them they're wrong? I've been here 3 days and I've already noticed this trend. Is this your standard operating procedure? 5 posts there... 5 posts where you asked questions you clearly already thought you had the answer to. You're not asking to learn. You're asking so you can bait someone and then tell them that they're wrong and it took 5 posts for you to get someone to get specific enough so that you could pounce on them with your "superior knowledge". Why are you here if you already know everything? You're certainly not contributing anything to the conversation and have served only to clutter up the original topic. Yay for you. You're smart.

I just like to rib people when they say things like the L67 has no top end (in regard to power curve, gearing is a whoooooole nother' topic)
Click to expand...
And you're missing the point. Regardless of gearing or power band a stock rocker 3800 tends to fall flat when you get to higher RPMs at highway speed. Rockers do wonders to awaken the "top end". You're not ribbing anyone. You're taking things out of context (purposely or otherwise) and then trying to show how superior your knowledge is. To anyone that's been doing this for any period of time your charade is pretty transparent.
 
Last edited:
Mike Kopstain said:
You're making my point for me... I said that adding rockers would alleviate the dead top end of the 3800.

Why do you ask all your questions as if you're setting someone up to tell them they're wrong? I've been here 3 days and I've already noticed this trend. Is this your standard operating procedure?
Click to expand...


get used to it, snowflake likes to stir the pot. thats how he works, does it all the time.
 
Oh Mike, I'm just messing around guy. I actually like you :o
But an L67 that makes the same peak whp as a LS4, with all things being equal, will beat the LS4 car.

:)
 
You must log in or register to reply here.
Back
Top