How much power is actually needed?

[vega]

The half shafts are being replaced with modern motorsport units. doing the cobra conversion. The stall is going to be custom based on the cam, which we are not positive on the cam (my head guy) until we get the heads and put them on the flow bench and see what we can do with the cross section. Not much really to tell here, suspension is adjustable, will be using the type 3 bumper kit, head light covers. I have not gone and replaced the hatch or hood or fenders with fiberglass or carbon-fiber. I weigh in at 145-155 depending if I defecated that day yet.

 

My big deal is I there are guys around where I am from running (stock mind you) 911 turbos, corvettes, built gsx eclipse cars, turbo Honda's, built 3sl cars. Not many are in the low 11's, I would like to be one of the not many. Hence my goal.

 

The car is not specifically setup for drag. We are putting it together for BIRs roundy course in MN. So keeping independent suspension is one of trickier deal for this seeing that irs blows for drag. Re-11 tires are basically long lasting (10k mi) autocross tires. I was planning on running 245/45r17s. If I needed bigger I was hoping to get a relative answer. If 245 was too small we would juts get a wider tire. Re-11 tires are the stickiest high performance tire on the market right now- with zero comparison.

[Turbo Meister]

I don't think the 11's are realistic for a 327 without a power adder. My personal experience lists traction as a top factor in successful and consistent drag race times.

My Z's best et with a naturally aspirated 383 was 11.15 at 123 mph. However, I had a backhalfed car with a Ford 9" and 12" rear tires. Best guess for hp was 450/500 flywheel.

 

A friend had a Z with a 421 engine. He only ran 13's because he could not hook up at launch.

[Pyro]

Want some real numbers, ok.

 

My 71 240 with a 450hp (crank hp) 362 cid (200cc dart heads (64cc), 292H comp cam, full length headers, rpm intake, 750 holley, 11:1cr, zero decked block, flat tops) with a T5 5 spd.

 

Ran 11.7 at 120 on the motor and 10.7 at 135 on a 200 shot on N02. And 1.5 second 60 footers with MT drag slicks.

 

After 120 mph, I had to change axle and u-joints much more often. An automatic trans might be a little nicer on the drive line. Over 130, maybe 5 to 10 runs before something broke.

 

And the 240z is lighter than the 280z. Never measured it but I would guess around 2800lbs with me in it.

 

ET is hard to repeat with questionable traction. However, trap speed will stay fairly consistent. First run I did with my V8 conversion was 12.7 at 110, second run was 14.0 at 110. Took a few years to tweak it into the 10's but then it wasn't fun anymore with all the rear end breakage.

 

As for suspension drag racing setup, start with the heavy springs in the rear and stock springs up front. And lose the front swap bar. This setup also cures front end plow (under steer)

[vega]

Want some real numbers, ok.

 

My 71 240 with a 450hp (crank hp) 362 cid (200cc dart heads (64cc), 292H comp cam, full length headers, rpm intake, 750 holley, 11:1cr, zero decked block, flat tops) with a T5 5 spd.

 

Ran 11.7 at 120 on the motor and 10.7 at 135 on a 200 shot on N02. And 1.5 second 60 footers with MT drag slicks.

 

After 120 mph, I had to change axle and u-joints much more often. An automatic trans might be a little nicer on the drive line. Over 130, maybe 5 to 10 runs before something broke.

 

And the 240z is lighter than the 280z. Never measured it but I would guess around 2800lbs with me in it.

 

ET is hard to repeat with questionable traction. However, trap speed will stay fairly consistent. First run I did with my V8 conversion was 12.7 at 110, second run was 14.0 at 110. Took a few years to tweak it into the 10's but then it wasn't fun anymore with all the rear end breakage.

 

As for suspension drag racing setup, start with the heavy springs in the rear and stock springs up front. And lose the front swap bar. This setup also cures front end plow (under steer)

 

That is what I wanted to know thanks much pyro!

[roger280zx]

Dad's old '55 chevy went 12.02 at 117. That was a 283 (.060 over) that turned an engine dyno to 498 hp, the other two just weren't there. He he. Not sure about race weight, but it was an all steel two door wagon, iron heads, 4 speed. I see no reason why a 2500lb car on modern tires (above times where run in the early '80s) could not run a second quicker with the same power. Driving style has a lot to do with E.T.'s and if you build a high winding 327 you will have to beat on it to go fast. It may have great torque and be plenty streetable, but you will have to drive it to hit those numbers. No one ever believed that little 283 would run like it did, but upon riding shotgun to my father slapping the rockcrusher through the gears at 8000+ the opinions would change. I say build it to your budget and see what it runs. If I turn out to be wrong and all these nay sayers are right... then you can spray it!

[vega]

Dad's old '55 chevy went 12.02 at 117. That was a 283 (.060 over) that turned an engine dyno to 498 hp, the other two just weren't there. He he. Not sure about race weight, but it was an all steel two door wagon, iron heads, 4 speed. I see no reason why a 2500lb car on modern tires (above times where run in the early '80s) could not run a second quicker with the same power. Driving style has a lot to do with E.T.'s and if you build a high winding 327 you will have to beat on it to go fast. It may have great torque and be plenty streetable, but you will have to drive it to hit those numbers. No one ever believed that little 283 would run like it did, but upon riding shotgun to my father slapping the rockcrusher through the gears at 8000+ the opinions would change. I say build it to your budget and see what it runs. If I turn out to be wrong and all these nay sayers are right... then you can spray it!

 

I would have gone 283 if it were not for the piston choices. Or more - the lack of piston choices...

Edited February 7, 2012 by vega

[vega]

No you are totally right a 333 ci motor will never see 11s....

 

 

(rolls eyes) fwd (there is a problem to start, imagine if it was rwd or awd) all motor (no forced induction or nos) small displacement (there goes your argument) high rpm 4 cyl (here comes some theory for you) Too much tq just spins tires and breaks stuff. you only need as much tq as it requires to get the car moving- the rest of it is hp. The 327 has plenty of tq. rotory motors don't make crap for tq yet are the fastest import cars(high rpm results in hp), rx7s that is using the motor that came in the car - modified of course. (ANYTHING not american - including german) Its the right parts, plain and simple.

Edited February 7, 2012 by vega

[Turbo Meister]

I don't think the 11's are realistic for a 327 without a power adder.

 

I'll amend that to say, unless you are willing to run a monster cam, high compression, rev to 7500 rpm, and not really have a very streetable car.

[Pyro]

And a 3.54 wouldn't be enough gear for a 7500 rpm 327.

 

Would need a 4.56 gear and a 4500 stall converter to use an engine like that. Not a street setup at all.

 

This is why NO2 is a good idea, as it also increases torque (even more so than hp). So can use less gear and stall.

[roger280zx]

Meister, you're points are well taken. You obviously know what you're talking about (see above wheels up sig pic), but this is hybridz... where there is no best and the title reads "How much power is actually needed?". I am sure that a very mild inexpensive to build 541ci caddy would do it with ease. Hell, a cheap turbo L would do it fairly easily, but the o.p. didn't ask what those would run or what it would run granny shifting at 4500. If I had to amend his set up it would be the gears. I think a 327 needs more than a 3.54 gear, or more torque (read power adder) to run that number, but that is just me. I would build as much engine as the budget allows and see what she runs.

[SUNNY Z]

while we're on the subject of small ci engines.......... Just a measly little stock bottom end 5.3

 

[vega]

I'll amend that to say, unless you are willing to run a monster cam, high compression, rev to 7500 rpm, and not really have a very streetable car.

 

I personally have highly considered a Procharger as I am fairly familiar with the units. I do not think that 7500rpm is needed, I would say max of 7000rpm. As far as a monster cam - it depends on what you define as a monster cam. Thus far (prior to deciding if I want to go blown or not) my custom cam of choice as previously mentioned; 110lsa 110icl (@50)236intake 247exhaust- as for lift I have to get my heads on the bench and see what we can do- a min of .52/.54 Which for the size of motor and where I want my power - this makes sense. If I wanted a purely top end hp car I would probably run a 195cc intake port (instead of the 190 i will be running) 250intake and 259exhaust I wouldn't even see power until way late which is not good for what I am actually using the car for (road race car). I also don't think nos is allowed even in open class for roadraceing if I remember right - I will have to check the rules again.

 

Again I am not here to try and explain why I am using a 327, I just wanted to know what kind of power I would need to get down the track with the gear ratios I have - with the weight (2800-3000max) I don't care to argue over something so small - you have your experiences with your big motors I have experiences with my small motors. Everybody happy!

Edited February 8, 2012 by vega

[vega]

while we're on the subject of small ci engines.......... Just a measly little stock bottom end 5.3

 

 

his suspension setup was for drag tubbed and the like, probably 4.10 gears (rx7) I will not be having a tubbed 4.10 datsun. Plus those first gen rx7s were way lighter than a 280z. Cool vid though. btw don't ls motors almost weigh what a iron old school sbc weigh because of pure mass even though they are all aluminum? I have been told they are the same size as a traditional 454. They are wicked motors though.

 

Why are ls motors making so much power anyhow? is it all heads/intake and ignition or what is so different between an ls and a sbc anyhow? I am not too familiar with the new blocks.

[SUNNY Z]

his suspension setup was for drag tubbed and the like, probably 4.10 gears (rx7) I will not be having a tubbed 4.10 datsun. Plus those first gen rx7s were way lighter than a 280z. Cool vid though. btw don't ls motors almost weigh what a iron old school sbc weigh because of pure mass even though they are all aluminum? I have been told they are the same size as a traditional 454. They are wicked motors though.

 

Why are ls motors making so much power anyhow? is it all heads/intake and ignition or what is so different between an ls and a sbc anyhow? I am not too familiar with the new blocks.

 

He runs right around a 3.00 rear gear. (dont need alot of gear when you have power and tire) The car weights about 2600#, so not a lot different. And you were terribly mis-informed about the physical size and weight of LS engines. They are basically the exact size of a gen 1 sbc, just lighter.

Edited February 8, 2012 by SUNNY Z

[vega]

http://www.zdriver.com/forum/timeslips.php

(the 10.8 z {zeta})

http://www.streetfire.net/video/datsunnissan-280zs-powered-by-lsx-engines-one-ha_93527.htm

 

Check that out

 

Well that just shows how little I know about the ls motors. What was done to that 5.3? (my 333 is technically a 5.4). Also what is so special aside the aluminum block of the ls?

[emeraldlion]

The new LS heads flow WAY better than the gen 1 heads. Stock ls heads flow as well as a lot of aftermarket gen1 heads. The only thing on the short block is weight savings, I don't think much else in the short block contributes to the power gains

[vega]

are the heads at a different degree? what kind of numbers at what lift are we talking here?

[rsicard]

There are aftermarket Gen I cylinder heads that outflow the LSx heads. GM LSx engines have traditionally had cathedral shaped intake ports. The latest design LSx heads have gone back to the rectangular intake port as they flow better than the cathedral port heads. They went full circle on intake port design. The LSx engine does not have that much advantage on the Gen I and II designs which was a lot more simple and easier to manufacture.

[Pyro]

There are also big differences in the blocks. Namely, low tension rings in the LS to reduce internal engine friction. And a roller cam.

[vega]

There are also big differences in the blocks. Namely, low tension rings in the LS to reduce internal engine friction. And a roller cam.

 

With the low tension rings would they also happen to be weaker though? Kind of like hypereutectic vs forged pistons? The hypereutectic last longer and have less friction BUT are not as particularly strong as forged?