Sup guys, got a question. I'm not a fan of these hypotheticals typically, but I just can't seem to decide for myself.

Righ now I'm running an L98 with a ZZ4 cam and full exhaust, built 700r4/2400TC and a 3.27 axle. I've been looking at the LT1 intake. My question is this: Do you think for a street car, the LT1 will kill too much low end? Keep in mind that this is not a strip car, so everyday driving is where it will need to perform. To be honest, my only complaint with my current set-up is the RPM range. The power is pretty good (at least for now), but it falls off too quickly.

Let me rephrase my question. Will the additional RPMs on the high end be worth the low end loss? All the dyno tests I've seen seem to be on more powerful motors that can really benefit from the flow. My motor is no slouch, but it's no speed demon.

Keep in mind this is a street car. The torque and the 2400TC really pull the car for "most" of my driving habits. I'm afraid the 3.27 may still be too tall if I lose more low-end.

This is purely an opinion question, and I'm used to looking at numbers. What do you guys think?

 

I would go for it...and maybee do some porting to the hgeads as well...

 

You won't miss the 15-20lb loss, when you get 60 extra hp at 5000 rpms. I'm betting it's worth it. I have a 5.0 and 2.73 and I'm going to do the swap.

 

Not when I'm rompin' on it at WOT, but how about normal driving? I whip around regularly between 2500 and 4000, but I don't wind it out all that much.

60 extra? I'm not quoting you, but damn, I was only thinking around 15 or 20.

 

15-20lbs loss isn't much considering how much torque these cars make. It won't give you 60 peak hp, maybe like you said 15-20peak hp, but it will give you 60hp under the curve. Which is sometimes more beneficial. You see what I'm saying? Like a spot towards 4900 rpm where the car makes 140whp, at that rpm it will make closer to 200 with a better intake. But your peak hp, stock L98 is around 215 or so, it will jump to 230-235whp. Which is around auto-LT1 numbers.

I'm hoping my car will jump to 210whp but fall back from 265wtq to 250. Still useable, but when i see the dyno graph, I'll know what gears to get.

 

If you spend the majority of you're time running from stop light to stop light, no, it wouldn't.

However, if you find that you spend more time on the highways... then yes, it'd be more than worth the low end loss. My old L98 was an absolute joke at higher speeds on the Garden State PKWY.

 

Well, I actually did some hands on research and looked at some stock LT1 dyno graphs at our cruise inn tonight. Like BigWhite said, the curve is really the story, not the peak, and I "think" most of the loss will be low enough to be absorbed by the TC.

....and I acquired the intake. My buddy had one and he said that I can pay him If I decide to use it, if not, it's just taking up space at my house now and not his!

 

Yes, look at enough graphs, you'll start to see how mis informed people yapping about "torque wins on the streen and an LT1 will lose to a TPI every day stop light to stop light"

TPI might have a higher peak, but everywhere outside of that very tiny spot where it eclipses the LT1, the TPI is getting stomped, the TPI just doesnt have enough to keep up. The LT1 (i'm referring to the whole swap since thats how i do em) drives great around town, more than enough "down low" to melt your tires, i mean really how much can you plant on the street realistically ?

 

With PE enable MPH, and AE work the answer is a lot.

Once again, comparing TPI to an LT1 intake is apples and oranges.

Interesting concept, but it's not really showing you anything unless you swap the entire engine. The manifold is just one part of what developes the torque line.

Whats the engine, ZZ4 cam, stock l98 otherwise, 9.3:1 compression ??

Since the LT1 is really just a singleplane intake with minor air distribution issues, you might want to consider modeling it vs TPI in desktop dyno. The actual numbers prolly will be 5-10% off, but the curves are usually very close.

-- Joe

 

Wanted to add one more thing.

When I switched from fully ported TPI setup, to a singleplane setup my car picked up 10mph in the 1/4, but at the same ET.

The car had been consistant all season before the singleplane, and consistant for the rest of the season after. (did it mid season). Car ran 12.40 every time. every pass. But the mph went from 110mph, to 119 mph. every time.

What does this tell us? That obviously the singleplane setup creates more POWER than the TPI setup did, especially on the top end. However, it did not create any additional torque (or much less for that matter) as the ET didnt change.

-- Joe

 

I do realize that the LT1 intake and LT1 motor are not the same, but I was more looking at the curve, and not the numbers.

Most of the curves that I see with LT1 intakes show higher HP up top and lower torque down low. Obviously the numbers will vary depending on LOTS of variables, but the torque curve is almost always flatter than other intakes. That's what I was basing my thoughts on.

I could nickel and dime this to death, but bottom line is this. I'm pretty happy with my current power, but I wish it wouldn't quit so soon. There's no such thing as good enough, I know, but my goal is simple: I want a bigger range of power. If I can rev 500 or 600 RPMs higher, lose a little torque, gain a little HP, I'm happy. (for now).

Not sure if that statement came across right. Does that make sense?

 

...that graph is a little scary.

Do you think the LT1 actually has less HP AND torque before 4000? I know is only the desktop, but that's exactly why I posted this thread. I want opinions.

 

What would those graphs look like with a set of AFR 180's or similar flowing heads?