Scarab vs Setback? The true test.

[Guest Z-rific]

Mike,

 

Allow me to disagree just a little bit. I have a Scarab stlye, yet I would love a "real life" comparison to see if it would be worth it in the future to change to the JTR. I am not one of those who will defend the scarab position beyond reason (I know some do, though).

 

Whoever drives the car, needs to be the most skilled and open-minded driver available. If you get somebody who is hopelessly pro Scarab, or pro JTR, we may never get an honest opinion. Maybe find someone who doesn't and has never owned a Z. That should give us a very objective opinion.

[Mikelly]

My recommendation for a driver would be someone NOT attatched to the Zcar world. Someone who doesn't have stake in the vehicle or its configuration. Also someone who is very familiar with torque and HP in small lightweight cars, but with V8 familiarity.

 

Mike Kelly

[Tim240z]

I vote for John Coffey as the test pilot!!

Tim

[Phantom]

Obviously the real answer is neither - put an LS1 in!!!

[rags]

Don't open the hood to show the position or better yet get a driver that doesn't know what Scarab or JTR positioning is.

 

Joe

[Guest billy383Z]

I would also love to see the results of this comparison. I have done the JTR swap on mine, and find that the car understeers a bit more than stock. I have a 700R4 tranny in mine, which is quite heavy and moves the weight bias a little bit farther back. I would like to see if a more forward weight bias would improve the handling characteristics of the car...

 

I am prediciting that the Scarab car MAY perform a little bit better in slalom/autocross events, and that the JTR config MIGHT be a little better in the ¼ mile on account of a little bit more rear weight assisting the traction...

 

FWIW, I have the B&M shifter in my JTR car, and didn't have to butcher the center console. I built a small sheet metal "pan" approximately 1½" deep and recessed it into the trans tunnel and then mounted the shifter into this pan. This will eliminate having to modify the shifter linkage between swaps, as the B&M shifter is cable operated.

[dsommer]

Cool idea!!!

 

Although my hybrid is interior gutted at the time I might be able to help (form a distance). My neighbor has an original Scarab and I have a JTR setback. So if you need any "original" Scarab measurements I'd be happy to obtain them for you.

 

Him 72 Z

350 iron head 300+ hp

4 speed

 

Me 73 Z

350 full (solid) roller, TFS aluminum heads 400 hp(?) (I hope I'm close!!!)

WC T-5

 

When I get my interior replaced (dash etc.) I'll see if he wants to do a little side by side comparison and I'll send you some notes/findings that you may or may not want to incorporate.

 

David

[flibuoy]

Chime in here with my experience...I bought a scarab type swap in a 240Z..and drove it for a couple months and elected to go to the JTR for a couple reasons. The handling part was not the motivator for me..I am not, and don't expect to become a good enough driver, to discern the diff between 49/51 and 51/49 AND this was a daily driver on STREETS. The change was worth 10 times the time and effort it tool because the long tubes no longer heat soaked the starter...the block huggers allowed lots of cooling past starter and car never needed a cool down in the succeeeding 4 years. That meant the patch of Ford type solenoid could be removed and less wiring connections. The move back and down let me put decent size droptop air cleaner on even with an aftermarket intake. The move back allowed a great fan shroud that allowed this driver to have a/c and idle in Houston traffic. This in turn let me take out oil cooler, trans cooler and extra fan in front of radiator. Was it worth it to me...you bet. After 4 more years after selling the first hybrid I am building my second...in JTR. IMHO and personal experience a street car is harder to build in JTR but was easier to live with and enjoy when done. Is it the only solution...nope...

john

[johnc]

I guess my real question is: Is doing this worth it to everyone to see the differences in it's most basic form?

 

Honestly, I don't think you'll see much of a difference. Changing a vehicle's weight distribution does affect handling - it usually makes it worse until adjustments are made to account for the change (springs, alignment, etc.) Granted, the weight distribution changes we're discussing are only a few percent so the "stock" 240Z suspension might mask the affects.

 

My prediction - the engine configuration that most closely matches the stock weight distribution will be the best handling.

 

As a magazine article it would be interesting reading but I don't think it would provide any real information. Kinda like the GRM article about a Honda Odyssey mini-van beating a Porsche 356 on an autocorss course.

 

If you do run the comparison you'll probably want more then 1 driver. I'd be happy to do this (I have no dog in this fight) and I can probably talk Bryan Lampe into driving too. He's a Cal Club ITS regional champ and works for bread and Red Vines.

[Guest yatsen]

My personal opinion on this is:

 

It doesn't matter. Those who have the Scarab setup are passionate about their setups. They won't believe anything that they don't want to. All it takes is looking back to the thread where Kim Blough and I went back and forth on the issue.

 

Mike

 

Is that a thread that you started? I did a search but haven't been successful.

[Guest zfan]

I may be wrong but I think that one was put to sleep it got a little too carried away.

 

Mike

[Guest yatsen]

What? Did it really turn into a religious battle?

[RPMS]

Just a thought here, on the scientific method. What you're trying to do is illustrate the difference between the Scarab and JTR methods, right? Well, changing ONLY the engine position won't give you the data you need to make a relevant comparison. All it will tell you is what differences can be attributed to changing your Center of Gravity and Polar Moment of Inertia. While CoG and PMoI are critical factors, they are not the ONLY factors that make differences between Scarab and JTR.

 

What I would like to throw out for discussion is this: How about testing each car in the manner a car typical of its breed is set up? Why choke down a Scarab with block hugger headers when one of the big benefits of the Scarab setup is that it allows you to run long tubes? It doesn't make sense. Long headers are an integral part of the Scarab equation, and they should be included if the test is to be meaningful. Since JTR cars can't usually use long headers, that is a meaningful and significant difference which should be accounted for.

 

Of course, everything else besides the driveline should remain the same in the tests. But I think you should equip the car in a manner which will allow each setup to perform in a manner typical of the breed. Otherwise, you're testing CoG and PMOI, not Scarab and JTR.

 

Does this make sense?

[Guest comeandzpa]

Scott,

That makes a lot of sense, assuming that this test is a comparison of the pros/cons of each setup, rather than JUST engine placement. If the test is just a test of location, w/ no mention of the potential performance and cost benefits of one from the other, then is it going to be a significant difference?

[SportZ2]

From what I've seen from these posts, the major concerns are:

 

1) Using the proper headers for each conversion and keeping everything else the same.

 

2) Compare the costs of each setup.

 

3) Determine setup difficulty for each.

 

If I'm missing something let me know.

 

I want this to be as simple a conversion as possible. I'm not here to compare an LS1 to a carbed 350 or am I going to test the differences between a manual and auto tranny.

 

This is strickly a baseline test to compare both conversions so that down the road when people are thinking of doing the conversion, they will have numbers to look at to help them decide which is best for them.

 

I also think that these tests should include a value or grade for each catagory. The tests I can think of off hand are:

 

1) Cost 2) Time 3) Difficulty level 4) 1/4 mile time 5) autocross 6) road coarse. Are there others?

 

As far as costs are concerned, I will have to figure out the normal cost as if I was starting from scratch, ie; engine, tranny, cables, mounts, etc. My true numbers will be incorrect since the engine cost me nothing, the tranny cost me nothing, I already have the mounts, cables, and everything else to make it work.

The only price I can remember from my 95 conversion was the custom driveshaft ($300) but that number is probably outdated by now. We will also have to have some astriks along the way when it comes to cost since some people will buy the kits and others will fabricate their own.

 

I want this to be a study on a basic conversion without getting caught up in the power side. I will dyno my car as well so people can see what a basic setup will do. I will also list all the work that has been done to the motor as well as work done to the engine bay.

 

Any last thoughts before I begin?

[RPMS]

Only one. You might want to consider the caliber of parts you put on each installation, and match them accordingly so that folks can't accuse the JTR of winning because it used $200 Hooker block hugger headers, and the Scarab had a set of generic $100 long tubes, or vice versa.

 

Just a thought.

[Guest drahgonking]

<edit> the reason you set the engine back is to get better weight transfer (read that hook up hard and haul ass) to reduce weight over the front wheels (read that better handling and less muscle to turn the steering wheel) and better balance (read that closer to the magic 50/50 front to rear weight bias) that also means better braking use common sense you do not have to test a nuclear bomb against a 45 caliber side arm to know the 45 will lose big time if you want to waste time and money put a corvette rear end a zl-1 aluminum big block and a trans that will handle all that in a z-car and see if it will smoke a set 13inch diameter by 6inch wide bias ply rear tires i am interested in the out come (heavy on the sarcasm) look guys jtr has spent alot of time working out the the proper set back to make there zcars handle accelerate and brake better so just buy the darn kit and enjoy it if you do not want to listen to me talk to the guys at jtr and ask for some specs on it

 

<editted by the moderators>

[Guest Z-rific]

First of all Draghon, please avoid paragraph long run-on sentences. Toss a "period" in there once in a while.

 

There are a lot of guys here who have spent many hundreds of hours building/modifying/racing Z cars. <edit>

 

There are some very experienced drivers who prefer something other than a 50/50 weight ratio. I'd be curious to see the numbers of a 911 Turbo vs. a Viper. Both cars handle extremely well, but I bet front to rear weight ratios are different.

 

What I'd like to see are some practical, real-life comparisons by experienced, neutral drivers. If the results come back "about the same" then I don't have to worry about losing my Super Comp headers, re-positioning my hood latch, and dropping my engine back a few inches.

 

Truth be told, all of our Z's are different. I have dropped the weighty front bumpers off my '78, tossed my AC, and removed every unnecessary bracket, wire, cannister, etc. from the engine compartment. So my Z will react different to engine placement than the next guys. Still would be nice to get real world comparison on both configs in the same car.

 

<editted by the moderators>

[Guest Nic-Rebel450CA]

Just as a note along those same lines Z-rific just stated, better weight transfer and 50-50 weight distro may not always be preferred. As I just found out with my Z (which has had some mods to be closer to 50-50) I actually had worse cornering as a result of the weight distro combined with weight transferring. I was having trouble with the weight transferring to the rear and consequently having the rear end get a little weird in hard cornering. I adjusted my rear springs up about 3/4" to put just a slight rake on the car to help keep the weight from transferring as much and now my Z is much more predictable in the turns.

 

There isnt any rule as to what weight distro is the best as it varies with driving style, type of driving and driver preferrence.

 

Also, I believe one of the popular rules of HybridZ is to not criticize others for their ideas...

[Guest Nic-Rebel450CA]

Why choke down a Scarab with block hugger headers when one of the big benefits of the Scarab setup is that it allows you to run long tubes? It doesn't make sense.

 

This brings up an important issue. Are we testing typical standard setup, or just the mount position itself?

 

I think that the engine should be prepared identically. Saying that you can run long tubes on the Scarab and not the JTR setup is not 100% accurate. If someone wanted to make full length headers for their JTR setup, they could. If you do not have the engine prepared the same then this also introduces other variables. Say, for example, that the difference in headers produces more torque. Also say that the additional torque makes for more wheelspin. Does this mean that the Scarab setup is more likely to spin instead of hookup? In this case, yes, but not in all cases.