Tony

The fine-tune customizes stock Geometry to suit you since Humans are not stock... If these are done in volume then manufacturing traits can be established i have found some interesting results. Comparison cars are the Lexus IS200 and the Mazda MX5, both multiple adjust Geometrically. IS200 suffers from significant front camber correction, followed with normal corrections in other angles around the car. MX5 suffers from global corrections. IS200 fine-tune showed most times the settling process violated the Geometry again, normally with diagonal displacement... this would mean another fine-tune would be required to finalise the Geometry MX5 fine-tune showed next to nothing Both cars are adjusted on a bed of ball bearings to eliminate friction. Both cars are re-measured after 2000 miles Both cars are adjusted at the wishbones So why the disparity Weight is the only answer. Seemingly the IS200 due to the weight resists settling regardless of the frictionless plates, whereas the MX5 due to the lighter weight is totally compliant. So from this what is learnt IS200 needs to be corrected... driven re-measured.... corrected, then have a 2000 mile fine-tune MX5 needs to be corrected and have a 3000 mile fine-tune A word of warning to IS owners, if these findings do prove as displayed then any Geometry without the fine-tune would be worthless!

Indeed the older Skoda does have an issue with the rear coil cup due to corrosion... what i have learned about the Fav is it has the front coils from the 00 Polo. The issue is that the Castor is more positive and the load on the coil surpasses the original position, in particular when turning with 'on' compression loading.... seemingly this is the weakest point.

Poor design.... the reason i targeted the osf is because i have seen several coils on the Fav broken there. Skoda are aware of the problem but as yet have failed to recall.

Excellent research Mark!

Let me guess OSF?

My guess would be the top mount. Reason is the activation left and right involves diagonal shear from the cars parallelogram... more prominent probably on a right lock. If the mount is loose it may knock by transmitting compression to the upper body housing.

Subject coil spring Vehicle: 02 VW Transporter Mileage: 78435 miles Location: Rear Normally factory wound springs are wound so that the compression pitch stays the same continuously through the coil. If the bump is intense the inner loops add to the resistance to the sum of many 1000's of lbs absorbing more and more intrusion. So it would be assumed that the coil contributes intense additions to the handling and general feel of the drive. How's this... and this The owner was oblivious to the condition, the reason it was brought to light was the MOT. Next problem was the replacement?.... most factory springs are 'normally wound' most after-market springs are 'progressively wound' With progressively wound springs the coil pitch gets tighter the closer the to the top of the compression, this has the effect of giving the spring more 'progressive' resistance', passive absorption in general conditions, aggressive absorption in the most desperate of cases. Oddly enough i now see one or two vehicles a week with a broken coil?.... does this reflect the new governmental canyon road condition we all hate but pay for?

There is a real problem regarding the workmanship correcting the Geometry and the final report you receive. That report permits you to view the workmanship but it's complicated to understand since the figures represent positions and forces, with luck this thread will help. Problem number one is the software. Once the car is measured the screen will display any angle out of specification as red, as the angle is adjusted the figures will turn green once it reaches the 'Specified range' this is wrong! and i have argued this fact directly at the manufacturers. What should happen is the figures should be displayed red when out of range, then yellow in the specified range and green at the target area/setting. To the print This particular car was pulling left, by email i asked the owner to have the Geometry measured, he did and was told nothing was wrong..... but there is... with the front camber... have another look! . . . . . . . What the technician failed to see because the camber is within the 'Specified range' and green is that the positions are in conflict NSF: 18' Positive so the compression is outside of the car OSF: 24' Negative so the compression in inside of the car In all 42' of push to the kerb.... imagine the vertical looking like this \ \ hence the pull. Problem number two. The specified range is the mechanical dynamics of the suspension when in motion taking all possible extremes of compression and release, but in truth this has 'NO RELEVANCE' to the information needed during a Geometry. If you are a mechanical engineer it may be of interest but other than that? To read the final positions try this... The actual position for all angles is the absolute centre of the specified range, in this example Camber front -50' to +40' the static centre is -10' for each front wheel. The complaint was the disparity in the front cambers, the failure was the software and the knowledge of the operator. My advice to you is look for the exact centre of the specified range. Also on this print there is another problem, not part of the complaint but it will become a future issue.... taking this lesson into account have a look at the rear Camber positions. . . . . . . Alarmingly the positions would be seen as green but the tyres will be worn to the wire in no time.. To reiterate..... The shop said there was no problem with the Geometry, it cost him £60. If it wasn't for wim's intervention he avoided a long expensive path to find a solution.

First i must say don't worry about the image problems..... There has been some malicious coding going through the forums and Scarface has limited protocol for a short period. To the car, Heavy damage indeed fundamentally panels and paint in truth. Knowing the Lex as i do Geometrically i cannot see a problem recovering the Geo A little tlc would conclude in my opinion. And Moffet.... nice to see you post .....you rascal!..... get the 'bug' and continue.....

I assume this is due to the Active Hydraulic suspension ?

Simply no. The polar centre and the angular yaw would not move nor would the centre of gravity. The roll % would allow lateral possibilities but the conclusion is totally dependant on the driver.... knowing you it would be absolute.... and 'stiff'

There is always a catch.... seemingly you cannot push more out unless the car breaths more in... 'ratio' is it 50/50 what is the expenditure? And i must ask....'Mapping' how personal is that?

Decatting is just part of the process of helping the engine to breathe more efficiently. Using the MR2 as an example, the first stage would be: 1) Induction 2) Downpipe & decat 3) Cat-back exhaust After which, the big bucks need to be spent: 4) Upgraded intercooler/chargecooler 5) Bigger turbo 6) Standalone ECU / remap Right now, I have 1,2,3 & 6 and have dyno'd at 295bhp (fly) compared with the standard 245bhp. Future plans are a TD06 turbo and Greddy intercooler to give around 300rwhp A comprehensive list indeed.... are these mods specific to the MR2?... can any areas be 'fine-tuned' or bypassed to cut out the middle area.. I wonder if i could own a stock MR2 and add 5+6 and dismiss the rest?....be gentle I'm just looking at the posabilities through the eyes of someone on a budget.

Ultimately i have to ask to what end! Is the De-cat really worth the expense as a stand alone modification... what BHP would it add if it was?.... TDI indicated that to enhance the de-cat other areas would need to be addressed to finalize the modification.... to me 'the novice' this makes sense because i cannot understand how 'one' modification offers a complete solution.... feel free to educate me!

Blonde moment, sorry. You obviously know a fair bit more than me (i'm still at initial book stage) but we both agree the initial turn off the turbo isn't exactly healthy for airflow and both agree the chamber after this again, isn't ideal. A replacement pipe, not having this chamber (i'm happy to post pictures of mine) WILL help airflow out of the turbo so will help, however small. Post the pictures! The likes of yourself, jap devil and TDIPLC are familiar with the conversation but people like me and any others watching this thread are not, and need as much help as possible to understand.

Governor...... your thoughts?

Indeed a subject close to your current needs. give me a trigger in this area to expand on and i will develop it.. Despite the introduction which needs to be expanded as i said.... the actual geometry was not mentioned.... this is in addition to the description.... pretty big this geometry lark don't you think! Center of gravity and roll centre, yaw and polar inertia add to the maths.... . . . . Give me a prompt

Imagine aerodynamics inside a pipe. The stock cat on an MR2 turbo comes off the turbo and enters the manifold. To fit a cat in this somewhat small space they had to make the pipe bulge like a balloon to fit all the ceramic in there. Taking the actuall cat out of this bulbus pipe would certianly greatly increase spool times on the turbo cars as the exhaust gasses would have a much smoother flow, however due to the non uniform shape of the chamber there would be a large amount of turbulance (or dirty air). A cat replacement pipe (as i have sitting infront of me waiting to be fitted) has a VERY smooth path for the air to flow as it never had to accomodate a cat resulting in near zero back pressure. To summerise cat out is good, replaced pipe is better. Tuning the exhaust on turbo cars is all about getting the gasses out as quickly and as uneventfully as possible, the replacement pipes aid this. Regarding the legalities, pre august 1995 MR2 Turbos don't have a model report for the MOT testers to match to so they go through the very lenient "default" test. Shame that HTH a little. Elloquently explained to a 'no brainer' like me in this area... nevertheless a valid question though! don't you think.

The centre of gravity is dependent on height relative to the wheel track, this determines the load transfer from side to side causing the body to lean. Centrifugal force acts at the centre to lean the car toward the outside of the curve, increasing lateral force acting on outside of the tyres. As seen here The centre of gravity height, relative to the wheel base, determines load transfer between the front and rear. The cars momentum acts at its centre to twist the car forward or backward, respectively during braking or accelerating. Since it's only the downward force that changes and not the location of the centre of gravity, the effect on over/under steer is opposite to that of an actual change in the centre of gravity. The effect is controllable by the use of the springs/ anti-roll bars or the roll centre height but with careful consideration to the roll angular inertia. Rearward weight bias is preferred due to the enhanced effects during the transition from the straight-ahead to cornering. During corner entry the front tyres are generating part of the lateral force required to accelerate the cars centre of mass into the turn. However the lateral force being generated by the rear tyres is acting in the opposite direction trying to rotate the car out of the turn. For this reason a car with 50/50 weight distribution will under-steer on initial corner entry. To avoid this most racing cars have a 45/55 or even a 40/60 weight distribution, this gives the front tyres the advantage of avoiding the cars moment of inertia reducing corner-entry under-steer. Questions welcomed.....

Seeminly not.... i know of a few from LOC who have had a de-cat and their cars still most the MOT.... just! most from LOC have only removed the pre-cats , the main cat remains, and will only pass the MOT if tested whilst hot the pre-cats are there to act as a primary cat untill the main cat reaches operating temperature I understand that...(just) but what pre-empted this thread was some MR2 SW20's that only has one cat... this made me wonder since the de-cat must has the same uniform shape as the origonal to fit.... To my mind there is nothing mechanical about an empty box so why pay the price for a modifyed unit?

Seeminly not.... i know of a few from LOC who have had a de-cat and their cars still pass the MOT.... just!

From the Geometry up i am blind to the modifications you guys do!.... but often i hear people mention de-catting to increase exhaust flow.... then i hear the price..... me being not so educated in this field i wonder this... 'Why not just remove' the existing cat and smash the ceramic out of it?... all that would remain is the hollow shell.... the cost £0... isn't that a de-cat?

Thats what i'd loke to do to a few fast fit fitters!! overtighten my nuts and expect the same. Make sure you hear the 'click'

'Have faith Luke'

But a 180 on a damp corner trying to drift I had a few BIG moments as my rears cooked into the sessions, not really sure how i caught them but i know i almost broke my thumb letting the steering wheel go from lock to lock freely! Great day, i can't wait to get her fine tuned and do another. Depending on how easily the camber bolts can be changed i might play on the day too instead of just playing with damping. The bolts are very easy to fit.... remove the top bolt... loosen the lower bolt... fit the EZ cam rotate it and watch how it moves everything.... then tighten everything back up... the beut about the EZ bolt is the Geometry positions with them are absolute.... non if the 1 degree or 2 degrees lark with other adjusters.