Bill00Formula

iTrader: (4)

This has been discussed alot in the past but I'm still confused. I know at some point the turbo car/or supercharged will blow away a N/A car but at equal rwhp levels, from what I've seen, an N/A car seems to do better.

For example say at the 580-600 RWHP level an N/A would trap 136-140 where a forced induction car seems to need around 700 RWHP. Am I missing something?

I thought the turbo would have a lot more torque so where is the disadvange?

I know there is a weight difference but not that much.

Thanks

rufretic

iTrader: (37)

I believe it's the curve. With N/A, you get in the power at lower rpm and stay in it. A turbo car will have less power down low but once you get in the high rpms they shine. N/A vs turbo with the same peak power, the N/A will usually ET quite a bit better too. I don't think it's very easy to make a 600rwhp N/A car, pretty rare. It's not hard to make a 700rwhp turbo car, pretty common.

An easy way to look at it would be to take 3 rpms, say 2500rpms, 5000rpms and 7000rpms of both cars, add up the power at each rpm and add them together. The car with the higher total should win.

turbo 2500rpm = 250rwhp
n/a 2500rpm = 350rwhp

turbo 5000rpm = 400rwhp
n/a 5000rpm = 550rwhp

turbo 7000rpm = 700rwhp
n/a 7000rpm = 700rwhp

turbo total=1350
n/a total=1600

n/a wins

At least that's the way I see it lol.

Villain281H

iTrader: (5)

Agreed that certain forced induction set-ups can take a bit to get to full boost, thus if comparing a similar rwhp figure N/A to turbo/blower in similar set-up cars, the N/A will likely win.

Derek

DMH Fabrication

iTrader: (126)

Also in general turbo cars will be heavier then N/A cars. Turbo, wategates, bov, intercooler, extra piping, etc. all adds up unless were assuming the turbo cars and N/A cars are the same weight.

Pro Stock John

iTrader: (34)

I think it's hard to generalize, but I think the NA cars tends to be lighter and more purpose built.

If compare my now turbocharged Formula to say an NA car that also could run 9.4, there are only a few, and most of the 9.4 motor cars would be for sure lighter. If I were to make my Camaro into a pure motor car to run 9.4 I'd probably try to get it to around 3100 raceweight vs. the current 3400 raceweight of the Formula.

rufretic

iTrader: (37)

I don't know too many N/A cars making 867RWHP lol, I kinda think your on a different playing field than the average N/A vs turbo comparison.

slow95z

iTrader: (33)

well most N/A cars can also spray which helps them get into the 800+ range. the power under the curve is why they are faster hp per hp.

ninetres

iTrader: (35)

Power under the curve????? WTF? It comes down to power and weight. Who leaves the line at 2500rpms????? I leave a 4k+ rpms and 10+psi.......in my turbo car. ANy real drag racing comparison will have to assume a decent driver which will keep the car in the peak power band the whole 1320ft.....not just the final 1200 ft, lol.

RAGENZ28

iTrader: (5)

It all depends in the build, not all turbo or blown applications are made for high rpm, I've seen motors make peak torque at 3500 rpm and still make 800 hp around 5500.

It's also a lot harder to make the same hp n/a vs. a boosted application, you want 800 hp from a n/a small block you're gonna rev the **** out of it, you want 800 hp from a turbo motor, piece of cake.

Whether or not the n/a motors seem to make more or less power under the curve, I'd take a lower rpm turbo motor over a high revving n/a setup every time.

Pro Stock John

iTrader: (34)

Good point Rufretic, I should have emphasized that when I went 9.40@143 on blower a few years ago, that was at 680rwhp. When I went 9.44@144 on turbo recently that was on less boost than when the car dynoed 867rwhp and the car had some issues that we found after that pass, wasn't able to make a follow-up one.

Bill00Formula

iTrader: (4)

I was wondering because I just bought a turbo kit from a guy on this forum. It's the speed inc. twin kit system w/ gt3582r turbos. I don't have it yet but from everything I have seen it seems to be an awesome system.

I had originally planned to build a ls7 block/ls7 head n/a setup maybe w/ the LG mototorsports package and hoped for 600 rwhp range. There are a handful of LS7 ZO6s doing that now. But the cost was so significant that I started to think if I get a turbo package I would have the potential of making more power and at the same time have great streetability (meaning enjoyable to drive, even in a partking lot). With that setup I thoughy that I would trap 136-138 range.

There is a local guy that has a 427/AFR setup thah probably dynos 520-540 rwhp range that traps 132-134 n/a. With a 400 shot of nitros he broke into the 8s at 153 w/ a 400 shot of nitros. His race weight is roughly 3500.

I don't need to compete w/ him (don't want to kill myself) but would hate to have 700 rwhp and trap less than 135.

NicD

iTrader: (7)

Turbo LS1s with "appropriate for the cubes sized" turbos are torque monsters and consequently area under the curve kings. If everything like weight, gearing, etc were equal and it was a turbo LS1's 500 rwhp against an N/A LS1's 500 rwhp I would put my money on the turbo car every time.

Area under the curve wins every time.

Pro Stock John

iTrader: (34)

Bill if you bought Tom D's kit you will have no problem making 600-800rwhp.

Now...

More cubes = more power on pump gas AND more torque AND peak power at lower rpm vs. a smaller cube engine.

A 427ci at 15psi (1 bar) makes double the power of what the 427ci can do by itself. So 475rwhp x 2 = 950rwhp or so. A 348ci at 15psi = 375rwhp x 2 = 750rwhp.

I made 867rwhp @ 25 psi, that's 1000 crank when you take into account the TH400.

Peepz do some smaller engines because they are (a) class restricted, (b) turbo restricted, (c) $ restricted.

If you make 700rwhp, TH400 or whatever, you should trap in the 140's unless you are like 4000 lbs. A 3000rweight car could go 8's with that power. I went 9.4@144 @ 680rwhp at 3450 raceweight back in 2005.

Bill00Formula

iTrader: (4)

Thanks for the replys.

Yes, I bought Tom's system. I have spoken to a couple people about the size of the motor. Seems like the 370 CI is very popular (at least the couple of people I spoke with) because of the bore / stroke combo (for reving). Also they talk about a back pressure issue which I'm not very familiar with in relation to turbos. In talking w/ Tom he said he increased the diameter of the y pipe so that may not be as big a problem.

Then some say the stroker is good match. Tom had a 428. I originally thought about doing an L92 stroker w/ L92 heads but some have said the quality of the L92 block has been a problem and the quality of the ls2 is much better. Seems odd that gm would make an inferior block considering all the technology that they have.

I'm leaning towards a 402 w/ l92 heads. Compression ratio? I was thinking between 9.0:1 to 9.5:1.

I also heard that an iron block is not needed till 750-800 rwhp level.

But I guess I'll find out soon enough. It will be interesting and hopefully alot of fun.

black_z

iTrader: (4)

I agree, if they are both behind an auto. In a stickshift car, I would probably take the NA car.

NBM2001z28

iTrader: (43)

You have to look at how a track determins your MPH. It isnt the speed at one point that takes your MPH. It isnt like a radar gun. The MPH is determined by the last 66 feet of the track. It takes the average of the time to go that 66 ft for your MPH. Basically everything is going to be determined by how the car works in the beginning... Thats why if you have a shitty 60ft, your MPH doesnt go away...

Burning Rubber

iTrader: (1)

I dont think its so much that NA cars are faster as they are quicker.