which motor would make more power

[Guest norm[T12SDSUD]]

I drop my exhaust so that saves me 15 lbs and I only run 5 gallons of gas and I remove my spare tire and tools so my race weight now is around 2370.

[JMortensen]

228whp according to the calculator. Still seems high by your estimate...

[Guest norm[T12SDSUD]]

Yeah assuming a 12% loss through the drivetrain that would still indicate 255 HP at the flywheel and I'm fairly sure I'm not making that much power.

[Guest bastaad525]

']Yeah I have never disagreed with the fact that Triples will provide more PEAK HP' date=' however on the street or a slow autocross track with slow turns I believe the SU's would out perform the triples due to their better low rpm characterisitics.

 

I have driven a number of triple carb equipped Z cars on mild cammed L24's and L28's and they were absolute DOGS below 4500 rpm compared to my SU's.

 

And as I said, other than Brian's car, I know of no other stock weight street driven Z with triples running comparable 1/4 mile times to my SU's and my engine is FAR from radical.

 

I think that SU's are the better choice for mildly cammed L6 engines like mine ,but cannot provide adequate fuel and airflow to support a radically cammed 3.1L as evidenced by Dan Baldwin's experience.[/quote']

 

 

This is EXACTLY what I"ve been saying all along. The only difference is that I'm debating that adding tripples and doing nothing else would give you 40 more peak hp on your average L6 setup (and certainly not on a stock engine... you NEED other breathing mods on the engine FIRST IMO, for the trips to do you any good at all!). And the example you posted from Dan Baldwin seems to support my argument... yeah he made 45 more hp, WITH CAM AND HEADWORK and then adding tripples. Yeah he notes a big difference at high rpm... while this is back to butt dynoing gain, I don't doubt that the trips did open the top end up nicely. On the other hand, as far as the actual peak power number, I'm betting the cam and headwork gained him more power than the tripples did, or maybe 50/50 at best Either way, it definately seems 40hp from just tripples is a pretty big leap, even on a worked stroker motor that would REALLY benefit from the increased breathing of the trips.

 

So, I do agree that:

 

1. Tripples will provide more peak hp over SU carbs, no doubt

2. Tripples seem to move the whole power band up (very similiar to how a bigger cam does), making more power higher in the rpm range, BUT, low rpm torque suffers

3. Tripples REALLY benefit much more on engines with more headwork and hotter cams

 

I mentioned above the example of me and this other guy doing back to back test drives of his tripple carb'd car and my SU'd car. I said the exact same thing Norm said... below 4000-4500rpm this guys car was a dog. He had the same block, pistons, head, damn near same cam as mine, and had had it dyno tuned at a place he claimed was all about performance Z's. He came back from driving my car saying he was sold and that he was gonna sell the trips to buy a set of SU's. This was his daily driver and he did mostly city driving and the lack of low rpm torque on his Z sucked. Given how relatively mild both of our setups were, I'm not surprised he didn't like the results.

 

Norm, I have used several 1/4 mile vs. HP calculators, and have dynoed on several dynos. My last few dynos put me between 226 and 233 rwhp. I've weighed my car twice and with me in it it comes to almost exactly 2600lbs with half tank of gas and spare. Every calculator I've tried puts me at 13.0 seconds at roughly 105mph. Anyways, I plugged your numbers into a couple of my favorite calculators (2370 with you in it? the envy I have for that car of yours knows no peer!!!!) and every single one of them puts you at ~225 rwhp. Every dyno operator I've ever talked to, as well as several performance oriented magazines that I read and subscribe to, all agree that RWD cars generally lose 15-17% thru the drivetrain. FWD cars lose more like 12-13%, and automatic cars lose 20-25%. You're more at like 260-265 crank hp if any of these calculations is worth a squat. Of course (and I say this with a BIG smirk on my face) none of these calculators takes your 'drive it like you stole it' technique into the equation So dude!!! stop being so modest, ya dun good on that engine ya built thar! Seriously

[briann510]

Dang, I just actually saw this post. I put the trap speed and car weight because I was getting alot of emails wanting that information so I finally just put it in the sig on here recently and zcar.com has had the times on there for a long time. even though we have vidoes up on my site with a 12 second run, people still dont believe it. i wish i had the camera with me on the faster runs. Rebello dyno'd us at 313 and that was before a big jetting change on the chassis dyno afterwards netting us an additionals 12 rwhp.

 

dyno to dyno on different days/different operators will net you way different numbers also. after several weeks of dyno runs i came to the conclusion the hp dont mean crap. the dyno is just a tuning tool or for some people bragging rights.

 

my son has raced pretty much everything around here and nothings beat him on the street yet. he stays neck and neck with me and my Z06 also. his launches are increadible on the street and he jumps 2-3 cars out in front on everyone.

[Guest norm[T12SDSUD]]

hey Brian when ya gonna put the beast into a lighter 71 240Z?!?! hehe

 

BTW kickass times. Did you run them on slicks, drag radials or street tires??

[Guest norm[T12SDSUD]]

Hey Baastaad it would be cool if I really was making that kind of power but I really don't know!! haha

 

 

BTW I am rebuildling the motor this winter. As you may recall it suffered two broken 280 crankshafts in 97 and 98 and then a broken diesel crankshaft in 2002.

I cracked a ringland on a lean out going balls to the wall in 3rd gear over 6500 rpm up a steep mountain so I had to tear it back down.Anyway it was actually good that I did as the #6 Main Bearing Cap was broken in two pieces!! I have no idea how long I ran the car like that as the bearing looked perfect believe it or not.

 

It obviously was cracked from the last diesel crankshaft failure but it was not obvious and I guess the vibrations from running finshed it off!

I think using the Diesel Main Cap Bolts torqued to 62 ft-lbs saved my azz from a major engine failure!!

 

I am putting in a new used block since this one had 280,000 miles of HARD ABUSE!! Also rememeber the block was missing the lower right corner section that got blown off in the clutch explosion of 1999.

 

I am doing some more headwork and adding a crankshaft scraper so I am hoping for a decent little gain in power!!

 

I need to get some slicks or at least some drag radials and see what the puppy can do this time around!!

 

Hopefully I'll have everything up and running again by April.

[briann510]

']hey Brian when ya gonna put the beast into a lighter 71 240Z?!?! hehe

 

BTW kickass times. Did you run them on slicks' date=' drag radials or street tires??[/quote']

If i had known the earlier years were lighter i probably would have kept looking for a 70/71. i didnt know squat about z cars before i bought it.

 

those were with 215-60-14 bfg drag radials spinning thru first and some of 2nd. well a hp upgrade will solve the heavier weight! this time next year we will have hopefully 550+ hp. also kicking around selling the engine and possibly going supercharged ls6. i pick up the YZ flares this weekend and begin chopping the rear wheel wells up for our 10" wide rear rims going on. we wont have a traction problem anymore with 335-50 rears going on.

 

it just never is fast enough!

[Guest norm[T12SDSUD]]

550 HP!!! Good grief!!! hehe

[JMortensen]

The only difference is that I'm debating that adding tripples and doing nothing else would give you 40 more peak hp on your average L6 setup (and certainly not on a stock engine...

 

So' date=' I do agree that:

 

1. Tripples will provide more peak hp over SU carbs, no doubt

2. Tripples seem to move the whole power band up (very similiar to how a bigger cam does), making more power higher in the rpm range, BUT, low rpm torque suffers

3. Tripples REALLY benefit much more on engines with more headwork and hotter cams[/quote']

40hp was what I was saying I got in my Z. Not what an "average" Z would get. My head had some porting and a bigger cam. 20% is what Mikuni claimed in their literature. The thing is the rest of the car has to match.

 

If you take a stock 240 with the widely spaced transmission and 3.36 gears on it and slap some triples on there it's going to be a dog. Using an induction system that makes its power in a narrower power band means using a transmission that will keep it in that power band, and using a differential that will get it into that power band quickly. I'm quite sure that most of the people who try triples and go back to SU's don't understand these things. So they put them on, realize that all of a sudden the car doesn't have any power until the top end (which means no power MOST of the time) then they take them back off and sell them on ebay. You gotta have the trans and diff ratio to work with the carbs. I bet he would have felt differently with a ZX trans and a 4.11.

 

Norm, I have used several 1/4 mile vs. HP calculators, and have dynoed on several dynos. My last few dynos put me between 226 and 233 rwhp. I've weighed my car twice and with me in it it comes to almost exactly 2600lbs with half tank of gas and spare. Every calculator I've tried puts me at 13.0 seconds at roughly 105mph. Anyways, I plugged your numbers into a couple of my favorite calculators (2370 with you in it? the envy I have for that car of yours knows no peer!!!!) and every single one of them puts you at ~225 rwhp. Every dyno operator I've ever talked to, as well as several performance oriented magazines that I read and subscribe to, all agree that RWD cars generally lose 15-17% thru the drivetrain. FWD cars lose more like 12-13%, and automatic cars lose 20-25%. You're more at like 260-265 crank hp if any of these calculations is worth a squat.[/b'] Of course (and I say this with a BIG smirk on my face) none of these calculators takes your 'drive it like you stole it' technique into the equation So dude!!! stop being so modest, ya dun good on that engine ya built thar! Seriously

I agree that you've done nice work Norm. I just don't think the calculations are worth a squat...

[Silent]

lets put it like this, both motors with good builds, nothing extreme, stop light to stop light, the su car will win. i have proven this time and time again here against another z guy with a rebello 3 liter and triples. and me witha 3.1 and su's

he has a steeper gear 4.36 vs my 3.90, same tranny, he puts down more power, but i get out on him about a car, and he does not start to come around me till about the 1000 ft mark at the track.

 

on the street, in a span of maybe 300 ft, light to light, i get him every time, BUT on the highway in excess of 90 mph, he creeps away from me.

 

he put down 230 rwhp

me? varies, last tim ei dynoed it was 163 hp with a flat cam, and he STILL doesn't walk all over me.

 

so it all depends on what the end user wants to do with the car.

 

 

btw, my su's with shaved throttle shafts, 260 spacers, and shaved jet bridge are the mods i did. him, full build, 45mm webbers

[JMortensen]

My experience vs a friends nicely built cammed L28 with SU's is different. From a stop, I can blow her doors off. From a ~60 mph roll, I can blow her doors off. The only time she stands a chance is if I slow down in any given gear to say 2000 rpm then floor it. That's when my car bogs down. If I downshift, I'm gone. You don't have to drive hers "on the pipe" though, which is why I would say that the SU's are a better street carb.

 

I've found that most of the people who drive triples on the street don't know what the hell they're doing. If you want to see some properly tuned triples, go to a racetrack. But those guys could give a crap about drag racing, and that's why, IMO, the triples get the bad rap. The difference between the two is freakin unbelievable, but I think I'm done trying to convince you guys. If only Norm would pony up for some 44's and tune them correctly... then you'd understand...

[Guest norm[T12SDSUD]]

Hey Jon, I'm a poor guy open to cash contributions for this test!!! HAHA

 

BTW, you were racing a GIRL!!! Only 1 out of 100 can even drive a straight drive effectively in a race!!

 

You put HER in your car and you drive hers and then we'll know what car wins the stoplight drag!!! hehe

[Tony D]

From the four barrel to the Weber 45 triples, we picked up 20 hp at 6500rpm, and our power peak was at 7500 (compared to about 6500 with the four barrel)

We then changed to TWM EFI (triple 45mm TB's) and gained 40HP over the triple 45 Webers at 8250rpm, meaning our power peak went higher to 8250 instead of 7500...

 

Carbs depend on velocity to make horsepower. The velocity is ALWAYS a restriction to horsepower. With a carb you will make more an more HP as long as you keep design velocity through the venturi and keep upsizing.

 

EFI is a bit different. First thing Andy said when he saw how much JohnC made was "I could have saved a lot of money using that manifold if it supports 287HP!)

 

But it wouldn't have LOOKED a good, Andy! LOL

[briann510]

I wished you lived by me so we could give the out of the hole stop light to stop light a try. we come out of the hole at 6K and there is no lagging period.

[Silent]

My experience vs a friends nicely built cammed L28 with SU's is different. From a stop' date=' I can blow her doors off. From a ~60 mph roll, I can blow her doors off. The only time she stands a chance is if I slow down in any given gear to say 2000 rpm then floor it. That's when my car bogs down. If I downshift, I'm gone. You don't have to drive hers "on the pipe" though, which is why I would say that the SU's are a better street carb.

 

I've found that most of the people who drive triples on the street don't know what the hell they're doing. If you want to see some properly tuned triples, go to a racetrack. But those guys could give a crap about drag racing, and that's why, IMO, the triples get the bad rap. The difference between the two is freakin unbelievable, but I think I'm done trying to convince you guys. If only Norm would pony up for some 44's and tune them correctly... then you'd understand...[/quote']

 

 

i fully understand the difference in the two, but im a cheap guy. so thats my reasoning.

 

i myself, plan on doing some big boy su's to see how far i can get with those, then switching over to triples to see how much farther i can go with that. with the su's on my car now, with the state they are in. it's not the greatest street car, it has it's issues, but you learn to live with them.

from 3500-6200 it pulls hard for what it is. runs with TT z32's {stage 2-3} on a high way run.

so, it's not like people don't understand, they just want to debate about it.

 

who knows

why not get all the su vs triple guys together in a race. and see what happens

drag, road race, auto-x and dyno

[Silent]

I wished you lived by me so we could give the out of the hole stop light to stop light a try. we come out of the hole at 6K and there is no lagging period.

 

 

gimme some drag radials and i'll be right there with ya!!!

 

ignore the bottle in the trunk, it's for looks i swear

[JMortensen]

I wished you lived by me so we could give the out of the hole stop light to stop light a try. we come out of the hole at 6K and there is no lagging period.

BINGO!!! At autox I sidestep the clutch at 3500-4000 and let the rears spin for a bit. If you let the clutch out at ease onto the gas at 1200 rpm you do get a vastly different result.

']BTW, you were racing a GIRL!!! Only 1 out of 100 can even drive a straight drive effectively in a race!!

This girl was a test driver for BMW. She really can drive, and she's owned Z's for the last 15 years. She's the exception to the rule...

[Guest bastaad525]

briann510 - okay I'll bite... just because I'm kickin around the idea of possibly keeping my car and going back to N/A.... how much do you think you'd sell that motor for if you sold it?

 

 

jmortensen - alright dude I think we're just gonna have to agree to disagree on this one I just can't believe that adding tripples alone is going to make 40 hp... unless we are talking on a full blown near race motor with extreme cam, lots of headwork, enlarged valves, bored/stroked... something like that that would just be really choked by SU's. 20hp, maybe, but not 40.

 

I found Tony D's contribution interesting as well... about the 4bbl swap to tripples. The only big ??? here is how that 4bbl would have compared to stock SU's...

 

 

on the subject of calculators, I have found that they can be fairly accurate though they tend to be MORE so in the case of RWD cars... as we all probably know a FWD car with the same hp to the wheels and curb weight will run a slower 1/4 than an exact same weight/hp RWD car. But it's basic math to figure how much hp it takes to accelerate a known weight and speed to a given distance in a given amount of time. Isn't that the very definition of HP?

 

If the calculators aren't enough, t's not hard to look at Norms times and weights and go and find other similiar cars (other 240z's making good power for instance, or other light cars like old miata's, MR2's... etc. etc.) and compare. Again... this won't take into account Norm's particular driving style... not sure how much difference that makes anyways, so who knows. But really... HP being so subjective... it's really not THAT important I guess But it would be fair and not at all dishonest to estimate his power at ~225 whp and ~260 crank hp.

[JMortensen]

I found Tony D's contribution interesting as well... about the 4bbl swap to tripples. The only big ??? here is how that 4bbl would have compared to stock SU's...

Remember that Tony didn't just run a Holley 390 and call it good. I think he had a 650 on there or something like that. I'm sure he was making a hell of a lot more than the guy who just slaps a 390 on and calls it a day. But I'm sure he'll speak to that.

on the subject of calculators, I have found that they can be fairly accurate though they tend to be MORE so in the case of RWD cars... as we all probably know a FWD car with the same hp to the wheels and curb weight will run a slower 1/4 than an exact same weight/hp RWD car. But it's basic math to figure how much hp it takes to accelerate a known weight and speed to a given distance in a given amount of time. Isn't that the very definition of HP?

So is it the dyno that's 40% off on the JNJ example? I agree with you that hp is a measure of work over time. But how else do you explain the 300 hp discrepancy? One or the other has to be wrong, don't you think?

If the calculators aren't enough, t's not hard to look at Norms times and weights and go and find other similiar cars (other 240z's making good power for instance, or other light cars like old miata's, MR2's... etc. etc.) and compare. Again... this won't take into account Norm's particular driving style... not sure how much difference that makes anyways, so who knows. But really... HP being so subjective... it's really not THAT important I guess But it would be fair and not at all dishonest to estimate his power at ~225 whp and ~260 crank hp.

Not dishonest. But maybe not accurate. So you could say that Brian has 278 whp or that I have 240whp, but what good is that if it doesn't relate well to reality?