ZF or TRW Rack - which is quicker?

Post by **PDenbigh** » Mon Jan 17, 2005 6:36 pm

Hey Guys,

Which is the quicker ratio rack - the 85-86.5 TRW, or the 86.5+ ZF? The ZF is the one with the "waffle" pattern.

Merkurencyclopedia says the TRW is the quicker, at 2.75 turns lock to lock. Some folks disagree. Others agree...

Could someone with a ZF rack please do a quick experiment and see approx how many turns they have lock to lock? I'll do the same with my (leaking and loose) TRW, and we can compare results...

Thanks a bunch!

Peter

Post by **PDenbigh** » Mon Jan 17, 2005 6:47 pm

Actually, I should be able to get the old one from Autozone by ordering the ATSCO 6441 Type 1 rack (vs. the "Type 2").

Post by **DPDISXR4Ti** » Mon Jan 17, 2005 8:57 pm

AlexD wrote:Even if you have the old rack, the new rack will be the updated rack the lastest rack made.

Sorry, but that's just not true at all. If you don't specify, you get whatever core they happened to rebuild last.

The later ZF rack is the quicker one and the one you want. I suppose the exception to that statement might be if you're doing a manual conversion on a budget by using a power rack. In that case, you might prefer the earlier TRW rack which gives you a little more leverage.

Post by **PDenbigh** » Mon Jan 17, 2005 9:05 pm

Well, I just tested my car, with the TRW (85XR), and it was not quite 3 turns lock to lock. A little more than 2.75, probably 2.85ish. Definately not over 3 turns though.

My rack has the smooth surface, not waffle.

According to MerkurEncyclopedia.com, irregardless of which is which, there are two racks. One has 2.75 turns lock to lock, the other has 3.4.

According to the manual, the later rack was the ZF rack, making mine the TRW, and since mine is closest to 2.75, it appears that means the TRW is the quicker rack?

Help me out here guys. I'm not trying to argue, I'd just like to come to a correct conclusion once and for all...

Thanks a bunch!

pyropete125 · Post by **pyropete125** » Mon Jan 17, 2005 10:06 pm

my rack is 2.5 lock to lock... but its a manual one from a fiero.

no its not a bolt in by any means.

pete

Post by **anglin** » Mon Jan 17, 2005 10:21 pm

pyropete125 wrote:my rack is 2.5 lock to lock... but its a manual one from a fiero.

Guess what - the stock ZF rack is 2.5 turns lock-to-lock too. I just went outside in this ridiculously cold weather to check it just for you, Peter! Okay, that's only partially true, I had to move my car anyway.

Now that I've seen the stock ratios of 2.75 and 2.5 for the TRW and ZF racks, respectively, here's some info about the 3.4 turns lock-to-lock ratio steering rack. That's the manual European rack. Ask Godfrey about it. I think he has one in his 3.0 powered XR. Grayson has driven it, so he can give you some impressions about it.

Post by **DPDISXR4Ti** » Tue Jan 18, 2005 12:04 am

I think John Vanlandinghambone got this one figured out for us. Apparently there were a few of the TRW racks with a similar ratio to the ZF - somewhere around 2.75 turns lock-to-lock. That's the first I've heard that, but it makes perfect sense given what Peter has found with the TRW on his '85. Bottom line, if you want a 2.75 rack, spec a ZF or you'll likely get a ~4 turn TRW. I suppose in Peter's case, he could have his 2.75 TRW rack rebuilt and returned, if for some reason he was into the whole originality thing.

pyropete125 · Post by **pyropete125** » Tue Jan 18, 2005 12:54 am

anglin wrote:
pyropete125 wrote:my rack is 2.5 lock to lock... but its a manual one from a fiero.
Guess what - the stock ZF rack is 2.5 turns lock-to-lock too. I just went outside in this ridiculously cold weather to check it just for you, Peter! Okay, that's only partially true, I had to move my car anyway.

Now that I've seen the stock ratios of 2.75 and 2.5 for the TRW and ZF racks, respectively, here's some info about the 3.4 turns lock-to-lock ratio steering rack. That's the manual European rack. Ask Godfrey about it. I think he has one in his 3.0 powered XR. Grayson has driven it, so he can give you some impressions about it.

i did it for 2 reasons: one less leak on my car and to make room for a nicer IC to intake pipe

pete

Post by **John Brennan** » Tue Jan 18, 2005 2:45 am

I have a waffle-pattern ZF on my '85, but it's not original. It has 2.5 turns lock-to-lock. The one in there previously had 3.5 turns, but it wasn't original, either.

The idea of simplifying/lightening the car by doing a power steering delete has its appeal, both as a way of ridding the car of a troublesome, noisy system and as a means to facilitate a turned or plenum intake install. I have always wanted to drive a car modded this way so I could see for myself how it affected the car's handling and agility, both of which are prized characteristics of the car in my opinion. I'm not too concerned about the difficulty of parking maneuvres or any of that, just how it would affect the car's street/road behavior. How quickly could I catch the tail, if I punched it out of a low speed corner and the rears broke loose? You guys who autocross or road race: what your take on this?

Jokerman · Post by **Jokerman** » Tue Jan 18, 2005 8:37 am

At a guess judging from driving my own merk and my old bmw 320i (78 E21) with a manual rack, i would say that from a purely sporting side that the manual rack will be nicer. At speed they respond quicker and give a bit more feedback especially when understeer is on the verge. The merks power rack is nice and does give quite a lot of feedback, but the old manual in my bmw just felt better bombing through a corner.

Post by **PDenbigh** » Tue Jan 18, 2005 10:18 am

anglin wrote: I just went outside in this ridiculously cold weather to check it just for you, Peter! Okay, that's only partially true, I had to move my car anyway.

Thanks for your sacrafice in the name of science!

From what I'm gathering, there are three types of racks that came in the XR!

However, the most important thing I think we have found is that although several racks might have the desirable ratio, the ZF seems to be guaranteed to have the correct one that will equate to 2.5-2.75 turns lock-to-lock.

I checked Autozone and Advance Auto last night, Autozone's is ~$140 vs. Advances' $300! I'm going to hit up Autzone and hope I don't get what I pay for

.

Thanks for the resarch adn contributions. I'll be sure to post this info on my site. If anyone knows the owner of Merkurencyclopedia, he might like to know these updates for his site.

Have a good one and stay warm!

Peter

pyropete125 · Post by **pyropete125** » Tue Jan 18, 2005 11:02 am

my engine bay looks nothing like that now... and everythig is comming out for my new motor

built long rod bottom end, esslinger aluminum oval head, SC-61 turbo and a few other goodies

pete

MerkXRTurbo · Post by **MerkXRTurbo** » Tue Jan 18, 2005 11:23 am

pyropete125 wrote:my engine bay looks nothing like that now... and everythig is comming out for my new motor

built long rod bottom end, esslinger aluminum oval head, SC-61 turbo and a few other goodies

pete

That's more or less where I hope to be in a year or so from now.

pyropete125 · Post by **pyropete125** » Tue Jan 18, 2005 2:08 pm

ive had most parts for over a year and a half now. i figured if i should get the stock motor to run right first before the $$$ parts.

so far ive learned: a/f ratio is crutial. timing is crutial. HG dont blow too often if everything else is in order. valvetrain geometery is the most critical part in cam selection. when installing new rings break in the motor correctly or else. aux shafts break with slopy dizzy shafts.

and a few other things im sure i cant think of.

pete

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ZF or TRW Rack - which is quicker?

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