dubulup

seems like he was helping...then a certain party took his help the wrong way and mouthed off.

bringing life, money, "what do you drive", and mothers into this ridiculous (and really shows who is childish)...the issue here is bump steer and how this 2JZ doesn't have the issues all others have encountered

jimlab

I see. So this thread is all about you, because you came here for help and couldn't get... oh, wait, no you didn't.

This thread was about someone else's project, and subsequently, their inability to give a straight answer to an important question about it. You missed that simple point and jumped to the conclusion (like Barban, who is equally dense) that I was attacking the conversion or that I was "jealous" of it, neither of which is the case. So let me spell it out for you (and Barban), since you don't seem to be able to do it on your own...

Your participation in this thread is unnecessary because the dispute is between roachdiddy and myself, not you.

All I'm looking for is an honest answer to my question, not that I expect to receive one. Roachdiddy is apparently as incapable of delivering a straight answer as you are of minding your own business.

Shall we start a poll to see how many members consider you a valuable source of information and how many think the same of me? Better yet, go search the archives. Let me know when you find a post you've made that people felt was worthwhile enough to save.

Despite your assertion that you have "a life", your ongoing participation in this thread proves the contrary.

jimlab

Apparently, it's a very difficult concept to understand.

roachdiddy

iTrader: (1)

my thread has been taken over! lol o well.
i keep hearing this "other 2jz swaps" but iv searched and searched for others who have built this same car... and nothing found other than sp's build. i have found many that have been started but never finished. could you please show me other 2jz swaps into fd's, that have been finished other than sp's car who have had this bump steer problem?
thanks

KaoticFdR1

http://store.driftingshop.com/2jzrxfdswdvd.html i'm pretty sure it's been done since they're taking pre-orders for the swap video...my guess would be its in the editing stages now.

http://youtube.com/watch?v=CIm98vah1qQ

dubulup

http://www.supraswap.com/index.htm

^here is a guy's project claiming no bump steer issues that never finished...

https://www.rx7club.com/other-engine-conversions-non-v-8-118/%2A%2Amy-single-turbo-wide-body-rx7-2jzgte%2A%2A-511211/

^here is another...

roachdiddy

iTrader: (1)

haha the second one is mine... read the name, that is this same project.
as for the second one he says no bump steer... id have to take his word for it i guess? ill be straight with you guys when mine is finished, bc ill be asking how to fix it if there is a problem.

the blue car you never see the engine and to me it doesnt sound like a 2jz.??

to put this whole bump steer debate to rest i guess we will all just have to see. im going to shoot a ton of video of the car. and if it has bump steer we will all go about thinking of ways to fix the issue...

88IntegraLS

There's always the option of FIREWALL PENETRATION.

Worked for me.

NOPR

I actually agree with Jimlab in this thread (scary). All I wanted to see was how you managed to fit the engine into the car. You either cut the hood or moved your rack. These are really the only options, and both are shitty options in my opinion. I suppose cramming it 8-10 inches into the firewall might work, but how practical is that? It would create a whole new mess of problems. Im still waiting to see one of these claimed 2jz swaps with stock hood and stock rack (in the stock location!), and it still hasn't happened.

jimlab

Nobody would think twice about butchering an FC.

Narfle

iTrader: (16)

Im pretty sure that was the joke, hence the tounge out emoticon.

I cant tell much more than the fact that bump steer will be an issue given its current, lowered location. The tie rods have to travel the same arc that the suspension travels which is achievable with the stock steering rack at only one height. If you look at the picture you can clearly see an upward slope of the tie rods on the way the the "spindles".

I'm assuming your problem is oil pan clearance. A little oil pan modification and rack mount spacers should raise the rack enough to correct the bump steer within an acceptable tolerance without sacrificing much oil volume.

You've put a lot of time, effort, and money into the project. Dont short-change yourself now. Take some measurements off of a stock cradle FD to find the optimal bumpsteer. And, heed JimLab with a grain of salt. He may lack tact(not that I have any whatsoever), but he's rarely off base.

Good luck,
Barban

roachdiddy

iTrader: (1)

thanks, and i will... just have to find the time and energy to put my old k memeber back into my other fd to take some measurements. the oil pan is close but not touching. the rack can be moved a little if needed, but ill have to see what i can do. maybe ill be the first to have the hood shut and no bump steer??? lol

88IntegraLS

Have you forgotten about various FC owners who claimed a V8 destroyed the very "soul" of the car? NW forum, about three years ago..........

jimlab

Better question... did I care?

Once you get past that silly horseshit, you're still talking about a car that you can pick up in decent condition for a couple thousand, five tops. You can't say the same for an FD, unless it has a sad history and a salvage title.

dsaggy187

bullshit i got my fd for 5000 cash and has a clear title and history its and auto with 130000 miles interior in great shape and the outside needs some paint and i am doing the 2jz swap in it so as soon as it is done the pics and video will be posted. it is not a cheap swap but i think it will be worth it in the end

jimlab

I'm sure it's an absolute cream puff.

130k miles, automatic, beat up paint... you got it cheap because no rotary lover would want it.

dsaggy187

ya rotary's suck tahts why and the whole point was to but a 2jz in it also my steering rackm is not being moved at all as for the hood it is n ot factory to begin with and for rear end the cobra irs diff will work for me so any other questions?

themonsterisme

iTrader: (2)

is there anyone on here thats done another zo6 ls7 swap and is there pics and how much bump steer correction has to be done?
and if im not mistaken the 427 is 50 lbs heavier?
and last but not least...this is for you jimlab...how or are you still able to use the factory gauges in the rx7 (tach,speedo) or have to switch to aftermarket or zo6 gauges because of the wiring harness???

jimlab

The same as any other LSx conversion, which depends on the engine cradle builder. The tie rod ends are moved downward with spacers to compensate for the change in position of the steering rack.

No. The LS7 uses a block that shares the same external dimensions as the LS1/2/3/6. It just has a crankshaft with a longer stroke and pistons that are larger in diameter (bore).

CID = bore * bore * # cylinders * stroke * 0.7854
Liters (L) = CID / 61.03

LS1 = 3.900" bore, 3.620" stroke = 346 CID/5.7L
LS2 = 4.000" bore, 3.620" stroke = 364 CID/6.0L
LS3 = 4.060" bore, 3.620" stroke = 375 CID/6.1L (6.2L, according to GM)
LS6 = 3.900" bore, 3.620" stroke = 346 CID/5.7L
LS7 = 4.125" bore, 4.000" stroke = 428 CID/7.0L (427 CID, according to GM)

Because the engine control harness and dash harness are separate systems in most modern cars.

The FD tachometer is setup for what is essentially a 4-cylinder signal and that happens to be what the LSx PCMs (Power Control Module) puts out. The FD speedometer is driven by an electronic VSS (vehicle speed sender) and the LSx PCM outputs a signal that can be adjusted to work with the OEM speedometer by using a device like the Dakota Digital SGI-5 or the Granatelli GranSpeedo. The FD fuel gauge sender doesn't change, and the water temp and oil pressure senders from the rotary can be used with an LSx engine by using adapters.

dsaggy187

i thought this was about the 2jz swap not a ls one

88IntegraLS

https://www.rx7club.com/showpost.php...&postcount=182


I know you don't care.

jimlab

Did you have a point in mind, or was this just more of the random meaningless bullshit you usually post?

wanklin

iTrader: (2)

They are also lengthened as we both know or else toe-in would occur during both phases of the suspension cycle.

I've pasted some pertinent information below from an older post (some of which was taken from other sites, some I created).

Bump Steer :

A. Definition Bump Steer is when your wheels steer themselves without input from the steering wheel. The undesirable steering is caused by bumps in the track interacting with improper length or angle of your suspension and steering linkages.
Most car builders design their cars so that the effects of bump steer are minimal. However, you must still take care to bolt on your suspension carefully so as not to create unwanted bump steer. Make sure that you are always using the correct components for a particular car. Bump steer must be designed into the car and cannot be adjusted out if improper parts are used or if pivot points are moved without considering bump steer design principles.
In order to accomplish zero bump the tie rod must fall between an imaginary line that runs from the upper ball joint through the lower ball joint and an imaginary line that runs through the upper a-arm pivot and the lower control arm pivot. In addition, the centerline of the tie rod must intersect with the instant center created by the upper a-arm and the lower control arm (See diagram below).
The instant center is an imaginary point that is created by drawing a line from the upper a-arm ball joint through the a-arm pivot where it is intersected by an imaginary line that extends from the lower ball joint through the inner control arm pivot. Where the two imaginary lines intersect is the instant center.
Sounds complicated? Really it is very simple. To achieve zero bump the front end must be designed correctly. The tie rod must travel on the same arc as the suspension when the car goes through travel. Simply matching lengths and arcs to prevent any unwanted steering of the front tires.
To exaggerate, if the tie rod were only 10" long and the suspension were 20" long then when the suspension traveled the tie rod angle would shorten much quicker than the suspension arc. In this scenario the tie rod would shorten much quicker through travel than the suspension and the car would toe in drastically over bumps. The shorter arc of the tie rod would pull on the spindle and toe it in through travel.
Bump Simplified - When designing a car, if the centerline of the outer tie rod lines up with the centerline of the lower ball joint, and the inter tie rod lines up with the lower pivot point then the length and angle of the tie rod and suspension will be the same resulting in zero bump. Most car builders design their cars in this fashion.

B. Preparing the Car for Bump Steer Measurement
front suspension must be complete and set for racetrack conditions before you can measure the bump steer. All components must be tight and in proper position and you will need a quality bump steer gauge.
1. Set the car at ride height.
2. Use the proper size tires and air pressures.
3. Caster must be set.
4. Camber must be set.
5. Toe in must be set.
6. Tie rod lengths must be set.
7. Steering should be centered (tie rod ends centered on inner pivot points lower ball joints).
8. Steering must be locked down.
9. Measure from the ground to the lower ball joint or other reliable reference point. Write the number down.
10. Remove springs and disconnect the sway bar.
11. Return the suspension to the proper height by using your reference number to the ground.
12. Obtain a supply of bump steer shims.
13. Bolt on the bump steer plate to the hub. Level the plate and note where the dial indicator is on the bump steer plate so that you can quickly return to the correct ride height.
14. Jack the suspension through 2"-3" of both compression and rebound travel and write down your results.
15. Shim as needed.

C. Making Bump Steer Corrections
Now that you have measured your bump steer you will need to adjust, shim or relocate the suspension components to get the exact reading that you desire. Below are some tips that will quickly guide you through the corrective process for cars with front steer style suspension.

Symptom Cure
Symptom 1. Toes out in compression and in on rebound all in one direction. Cure 1. Decrease shim on outer tie rod or lower the inner tie rod.

Symptom 2. Toes in on compression and out in rebound all in one direction. Cure 2. More shim at outer tie rod or raise the inner tie rod.

Symptom 3. Always toes in both compression and rebound. Cure 3. Lengthen the tie rod as it is too short.

Symptom 4. Always toes out on compression and rebound. Cure 4. Shorten tie rod as it is too long.

Symptom 5. Toes out on compression, then in on rebound and then starts back towards out with more rebound travel. Cure 5. Less shim at outer tie rod and shorten tie rod.

Symptom 6. Toes in on compression, then moves out on rebound and then starts back towards in with more rebound travel. Cure 6. More shim at outer tie rod and lengthen tie rod.

D. Using the Bump Steer Gauge
Selecting a good bump steer gauge makes the process easier. I like the bump steer gauges that utilize only one dial indicator. One dial indicator bump gauges do the math for you and you avoid having to watch two dial indicators move at the same time. Sometimes when the bump is way out of adjustment it takes two people to watch both of the indicators. The one indicator design is much easier to use.
When you set up your bump steer gauge with the car at the proper height set the dial indicator at the center of the bump steer plate and be sure that the indicator is set in the middle of its range. You want to avoid running out of indicator travel.
Once the indicator is set simply jack the suspension through 2"-3" of compression. Stop at each inch and record your reading. Repeat the process through rebound and record those numbers at each 1-inch interval.
If the front of the bump steer plate is moving towards the engine then you have a bump in condition. If the front of the plate moves away from the engine then you have bump out. The dial indicator will see small amounts so watch it carefully and note your results.



F. Diagram



Here's my uderstanding as steering geometry relates to the FD. Essentially you have the upper arm pivot points (blue) and lower arm pivot points (green) and there coinciding ball joints. You essentially draw an imaginary line from the center of the ball joints through the A-arm attachment point on the car for each A-arm and where these lines intersect is the "instant center." Your steering rack should be mounted so that the inner pivot of the tie rod end lies in line with the line intersecting the upper and lower pivot points and the tie rod end should be attached in line with the line intersecting the upper and lower ball joints. Additionally, the tie rod should be angled in such a way so that an imaginary line drawn through it will intersect with the "instant center."

As long as all of the prerequisites are met it seems that the arc of the tie rod end will be in phase with the arc or the suspension components during bound and rebound.

Given that the inner pivots cannot be adjusted on the tie rods, the relocation of the steering rack, for a motor swap for example, necesitates that extensions be used to compensate for the shifting of the inner pivot point of the tie rod. If a steering rack is lowered, such as in the case of an LS1 swap, the tie rods must be extended both outwards and down so that the tie rod angles will intersect the imaginary instant center and therefore maintain proper arc.

This is my very basic understanding, though I'm sure that there are others who can touch a bit deeper on the subject. I would be interested to read more about the Supra7 to understand why they were never able to correct the steering geometry of the car. If you do a visual comparison of the Supra7 rack VS. LSX VS. stock you will see that the Supra7 rack was not moved noticeably more than we are moving our racks for our LSx conversions.... With that said, the bump steer and driveablility issues that 2JZ swappers are facing are the result of CG, PMI and bumpsteer issues.




In order to prove the relation of the arms to the instant center I made a model out of paper creating the proper pivot points and fixed distances between ball joints and pivoting points. Since the steering tie rod end is fixed to the wheel up right it's distance from the hub is therefore fixed and it will always point towards the instant center. If you don't believe me you can try it for yourself


You shouldn't need to install the rack to take a measurement since you can just lay the custom rack and stock rack next to each other and take measurements using the referencing the chassis mounting points. There will no-doubt be mounting slop to take into consideration, but it should give you enough information for you to know basically where you will stand once the bolts are torqued.

GL
Rob

jimlab

Which would be taken care of during alignment...

wanklin

iTrader: (2)

^Not if the stock tie rod arms don't reach