positraction

[zr1_racer]

Hello All!

I'm the proud owner of '93 #176 ZR-1 (368 Lpe) and would be interested in your opinions, advises concerning modifications under work or planing. In the vast majority, you're more experienced than me in the ZR-1 field or some other fields of expertise, so I would really appreciate your opinions.

First of all, I must say that I'm not interested in NCRS guideline rules if you see what I mean. My first goal is sensations, pleasure, music of the engine, low weight, general balance, low parasitic losses, ... in one word: ultimate efficiency. I don't drag race but I do road race from time to time. And I'm willing to try to improve the whole driving / racing experience without deteriorating the ZR-1 spirit.

Here are some of the said improvement fields for the engine and transmission:

- bosch injectors.
- electric water pumps with electronic regulation (warmup, shut off cooling phase, performance, economy, ...).
- electrohydraulic powersteering pump.
- no air conditioning
etc...

Later on, for the whole driveline, I plan to work and hunt for the parasitic losses.
For instance, the goal in the rear end is to test a less viscous oil without any limited slip additive. A torsen type differential allows me to do that. More than that, it also gives a better ride on bad roads, the behavior of the car is safer, more predictable. It's a real plus.

So... my question is about the choice of the torsen type differential. I plan to use a Truetrac TT 913A590. It is said to be for Dana Spicer 30 spline axles. This one fits 3.92:1 ring gear ratio and above (I have a 4.10 to1).

Do you think it will fit inside the case of my Dana 44? I know that there is some machining to do on the side yokes so that they don't move out so I can fit a snapring on each (if I understood well some explanations on the other forum...).

Thank for you replies, comments, advises.

David

[kenthompson]

Ok, this is the second time I've seen electric water pump for a LT5. What gives? Does somebody make a kit?

[zr1_racer]

Hi Ken

Thank you for your comment. It's not a plug and play kit. You have to fabricate parts to install it. I'm going to use the craig davis water pumps with electronic regulator and without thermostat as the manufacturer advises.

Technology moves on so I will be happy to use better quality parts when available: better performing injectors at a fair price, lighter and smaller battery, more efficient water pumps. These ones do not cavitate, do not rob as much power, do not necessitate a by pass system and improve the cooling of the beast (my car has a Ron Davis radiator).

The same for the power steering pump which works fine when you're idling in the straights and do not rob much power in that case, but needs a radiator when you're going in the upper rpms and then is evidently wasting power. Nothing revolutionnary, only what the manufacturers are doing now on last generation vehicles.

[8upZR1]

On the net registry site you can find a beautiful pic of the H20 routing of the LT5. Studying this thoroughly really helped me.

I have read on some post here that you should not get rid of the H2O bypass for any reason. You can buy a set of underdrive pulleys for the factory pump. Also, with a remote electric pump you have to do something with the belt routing scheme if you ditch the oem pump completely. I dont think the design is all that bad. Just needs to go slower with earlier fan on Temp. I would put a restrictor in the outlet of the radiator and swap the thermostat's 2nd disc for a fully circular one instead of the figure 8 that lets water go by.

I am waiting on an adapter plate from my waterjet people to us a ford hydroboost in my zr1. It still runs off the P/s pump, but you can use the hydraulic prssure it makes for all sorts of stuff, for instance ford makes about the thinnest 18" radator fan in the world, and it is controlled and run by the hydraulic pressure from the P/S.

Something to think about before you add up the amperage draw of all your major pumps and find out the alternator isn't gonna be happy.

I think it wonderful that you want sensation over nccrs whatever piece of paper saying your ZR-1 is a certified Chevy. Way more Zr1 owners need to jump onto that line of thought. You should consider NOS. Goodluck.

[kenthompson]

I am waiting on an adapter plate from my waterjet people to us a ford hydroboost in my zr1.


My experiance with hydroboost is that it does not react quickly enough to be put in performance applications. For whatever reason, there is a somewhat lengthy delay between pedal activation and actual brake application.

YMMV, but all my experiance was from the original application of hydroboost, 1-ton trucks.

[zr1_racer]

On the net registry site you can find a beautiful pic of the H20 routing of the LT5. Studying this thoroughly really helped me.
I agree with you but I can't find it anymore :icon_scra. I'm going to search through the archives of the listserv.

I have read on some post here that you should not get rid of the H2O bypass for any reason. too much pressure with stock radiator and water pump. Not a problem with the electric system which is weaker in peak performance but more efficient in the long run.

You can buy a set of underdrive pulleys for the factory pump. 10 hp saved and better reliability efficiency in warming phase, cooling phase (water pump still working when you switch off the engine ....)

Also, with a remote electric pump you have to do something with the belt routing scheme if you ditch the oem pump completely.
Yes, I'll keep only a 3PK belt instead of the 6PK and with only the alternator. Nothing else beside the belt tensioner of course. New low drag bearings, etc...

I dont think the design is all that bad.Not that bad, I think but less efficient for sure

Just needs to go slower with earlier fan on Temp. I would put a restrictor in the outlet of the radiator and swap the thermostat's 2nd disc for a fully circular one instead of the figure 8 that lets water go by.

I am waiting on an adapter plate from my waterjet people to us a ford hydroboost in my zr1. It still runs off the P/s pump, but you can use the hydraulic prssure it makes for all sorts of stuff, for instance ford makes about the thinnest 18" radator fan in the world, and it is controlled and run by the hydraulic pressure from the P/S. Hum I didn't know that!

Something to think about before you add up the amperage draw of all your major pumps and find out the alternator isn't gonna be happy. I think it will be ok. Quite low consumption and no Pimp My Ride accessories beside that...

I think it wonderful that you want sensation over nccrs whatever piece of paper saying your ZR-1 is a certified Chevy. Way more Zr1 owners need to jump onto that line of thought. You should consider NOS. Goodluck.
I agree with you. Some interesting "new" technologies can be used on our old cars. I plan to use a few "tricks" not to make power but to save power through the whole car (driveline, engine, ...) and gain a LOT: goal is 100hp.

[zr1_racer]

My experience with hydroboost is that it does not react quickly enough to be put in performance applications. For whatever reason, there is a somewhat lengthy delay between pedal activation and actual brake application.

I have a friend who is installing an LS1 in a C3... with hydroboost, I think he will be happy to learn this. :neutral: I didn't know that either.

David

[Paul Workman]

You get the Artie Johnson (from "Laugh-in") "Veddy intorestink" award!

I'm intrigued by the engineering progressions of automotive engineering toward the performance levels we're seeing today. So, teaching our old dogs a new trick or two would be very interesting (to me) for sure. Let us know the (scientific) before and after results!

For the most part, the focus (especially in magazine articles) and discussions on this and other boards is centered on making more power to get better performance - almost at the exclusion of efficiency. (But, then...the LT5 is pretty damned efficient at making power/displacement, methinks)

More power to ya (pun intended)!!

P.

[zr1_racer]

Hi Paul!

I lastly read an article in "Professional Motorsport Magazine" about the efficiency in gearboxes in formula 1. Nowdays, parasitic loss in Formula ones transmissions and probably other high end technology vehicles is 2%. Not 15 or 12 like it might be in our cars (I'm not talking about tires), but 2%.

My goal for this part of the car (transmission) is 50% gain. Thanks to tribology work, special bearings, very low viscous oil in transmission and rear end, low drag seals, in transmission, low drag wheel bearings, etc ...

Just add the following things:
- optimized efficiency of the whole transmission. See my question in the subject? ;-)
- no cats
- low drag accessories on the engine (rebuilt alternator with ceramic bearings, and sligthly larger alternator wheel, shorter and thiner belt, ...)
- new injectors
- vacuum pump
- I now have 12.5:1 compression ratio.
etc, etc ...

100 hp is about 85 hp at the rear wheels. So I don't use NOS, I use efficient dynamics and save for more power and fuel efficiency. Both worlds. Not cheap (and a lot of home work) but very interesting.

[Aurora40]

100 hp is about 85 hp at the rear wheels.
Of course it won't be once you improve driveline losses... ;)

Have you done the math on your goal? If your 368 was putting down 450whp, that would mean it loses about 80hp in the driveline assumng 15% loss. If you cut the driveline losses in half, that would only buy you 40hp. Add in 10-20hp in accessory loss improvements and you are still a ways from the 100hp goal.

I was just wondering if you had a map of how you get to 100hp. It sounds like a pretty cool project, though. Sorry no one so far has had any info on your Torsen question, I'd guess you'll be the first person to try it.

Have you thought about shedding weight instead, or along with, of shedding driveline loss? I wonder which is actually more difficult/expensive to do? I look forward to hearing about your progress. :cheers:

[zr1_racer]

Of course it won't be once you improve driveline losses... ;)You're absolutely correct Bob.

Have you done the math on your goal? If your 368 was putting down 450whp, that would mean it loses about 80hp in the driveline assumng 15% loss. If you cut the driveline losses in half, that would only buy you 40hp. Add in 10-20hp in accessory loss improvements and you are still a ways from the 100hp goal.

Let's say this ZR1 with standard equipment puts out 530whp that is 450rwhp.
Add:
- bosch injectors: +10 hp
- no cats: +15 hp
- no accessories but alternator: +20 hp
- vacuum pump: +10 hp
So the power getting into the gearbox is now 530+55=585hp

Now remove a quite conservative 10% (I hope, time will tell...) and you get
527 hp.

With a non optimized drivetrain, you would need 620 hp ... not far from my non effective 630 hp goal at the flywheel.


I was just wondering if you had a map of how you get to 100hp. It sounds like a pretty cool project, though. Sorry no one so far has had any info on your Torsen question, I'd guess you'll be the first person to try it.
Thank you Bob. Informations are welcome , I have virtualy no experience with Dana 44 rear end work.


Have you thought about shedding weight instead, or along with, of shedding driveline loss? I wonder which is actually more difficult/expensive to do? I look forward to hearing about your progress. :cheers:

Yes weight and aerodynamic too (floor) but with moderate modifications.
Superfinishing of parts is not very expensive. What is demanding is time, some coatings, hybrid ceramic bearings,...

Thanks for your support Bob! :wave:

[blackjack]

im really interested to see your results,as i agree with you...there are a lot of minor improvements to be gained if one sits and think about it...underdrive pulleys...synt. oils...weight removing(excluding dieting) , etc...let us know how it goes,and good luck
bj
91/1735

[zr1_racer]

Thank you BlackJack! I will for sure keep the community informed!

David

[Locobob]

You're absolutely correct Bob.



Let's say this ZR1 with standard equipment puts out 530whp that is 450rwhp.
Add:
- bosch injectors: +10 hp
- no cats: +15 hp
- no accessories but alternator: +20 hp
- vacuum pump: +10 hp
So the power getting into the gearbox is now 530+55=585hp

Why do you think you'll get 10hp out of Bosch injectors? Do you have some test results / evidence of a hp gain with these? I saw a video recently that showed the Bosch design 3 spray pattern compared with other brand name injectors, it looked good in comparison but I wonder if this will actually translate into a hp improvement.

Cats: Assuming you already have headers from what I've heard you will only net about 5hp by removing high flow cats (aka Random tech 3in).

The vacuum pump is an interesting idea, I think Kurt White played with this idea some time ago and netted a small gain. I have been wanting to try this myself. My thought is to rig a small electric pump to a micro switch on the throttle body for a full throttle only activation.

[bradslt5]

on the vaccume pump . corey did his masters paper on the effects of a vaccume pump on the lt5 and said it netted no gain at all . you might double ck with him but he put alot of work into the project , being it was his final .

[kenthompson]

im really interested to see your results,as i agree with you...there are a lot of minor improvements to be gained if one sits and think about it...underdrive pulleys...synt. oils...weight removing(excluding dieting) , etc...let us know how it goes,and good luck
bj
91/1735

Double goes on the dieting. Gotta maintain our girlish figures now.