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crankwalk Dork
4/3/17 5:34 p.m.

Love your idea with the ducts for the intercooler. With those ducts and that thick of a core, I'm sure it will be more than enough for that turbo.

Ironsides Reader
10/23/17 9:36 a.m.

Been a while since I've updated, it's also been a while since it came out to play.

Did a grand total of 3 complete autocross events this season with the car (fail) It remained broken most of the season while I tracked down electrical gremlins. 

I finished mid pack this past Saturday, only about a half second off the 2-3 cars ahead of me. Car has all the power I need, but still needs some help in a few areas.


Problem #1: the brakes still suck, they're spongey and the pedal travel is a bit too far. Everything is functional, I feel the issues at hand are the abs system and potentially a leaky booster. 

Solution: Convert the car to non-abs, I have the factory bits to do so, remove booster and replace with a Wilwood compact 3/4" unit (have the bits to do so as well)  Then Reevaluate.


Problem #2: Steering input, I'll admit, I ran zero front toe this past weekend and after driving my BRZ most of the season, I forgot how much steering input was needed to get the car to turn in (17:1 rack LOL) The car was understeering pretty hard until I realized I simply wasn't used to turning as much as the car needed. after that things started to work better. There is room for improvement here, the car still has a tendency to understeer a bit. 

Solution: Planning to try 1/8 - 1/4" toe out and see if that helps first.


Overall the car could loosen up some in the back and it could use some more front grip as well, but I feel like im on the right track! 


Few pics from saturday:




Friends turbocharged focus zx3: 



Ironsides Reader
3/31/18 7:06 p.m.

Now that the weather has broken I decided to break the ole girl out of storage. Promptly too for a good tear through the local forest roads, man did I forget what a torque monster it felt like in comparison to my other cars. Now, to solve my mushy brake pedal... :)


Tillerman New Reader
4/1/18 11:47 a.m.

Love your Probe. More updates please!

Tillerman New Reader
5/6/18 4:37 p.m.

Nice work - thanks for the update.

Ironsides Reader
6/17/18 10:00 p.m.

Got the GT out to an event yesterday, drove worlds better I will explain in detail changes tomorrow. Cooling fan crapped out once again unfortunately but was able to finish out the day. Fastest run of the day, finished 14/30 in a catch all class behind some prepped Miatas, a gt350 and several e-street mr-s's. Pretty happy with that. Car feels like it has much more in it with some tweaking. 


Ironsides Reader
9/18/18 5:01 p.m.

It's been a while since I've updated this thread but I have been quite busy with the car. 

Following the cooling fan failure, I found that the threaded motor shaft had sheared, thus detaching the fan from the motor and causing the heat management issue. I decided the to avoid any more cheap ebay or no name fan units and upgraded to a 13" SPAL puller fan. Since installing I have not had any more issues :)

I did however end up on a flatbed for the first time, I had been driving it for a couple weeks to and from work and discovered a leaked fuel hose clamp that I could not reach with the travel tool box. Given that it was directly above the downpipe, I didn't want to risk a sprint for home base. 

The following weekend I had the chance to do a two day "autocross" event on a local track in NH. In preparation I had picked up some mustang wheels and mounted a reversed staggered set of r-s4's to experiment with adding as much grip as the stock body would accept. (245f /225r)

Had a blast, the car drove quite well! Pinched tires in the front meant higher pressures were needed but overall it was a successful improvement.

Couple weeks later, the proper sale presented itself and I was able to shave quite a bit of weight out of the heavy mustang wheels.

This time using a 17x9" wheel to maximize the contact patch on the front 245's. 

At this point, I found the handling shifted a bit too far to oversteer, due to the combination of the wider front track and big rear bar. (Pretty wild feeling on a FWD car) The first autocross event with the combination turned the car basically into a drift car when driven in anger. 

I swapped the stock rear sway bar back in for the next event the following week and the ole probe felt 100% better. 

At this point the season is winding down, I did convert the brakes from ABS to non-ABS to resolve the soft brake pedal. 

While this did help with brake feel/feedback, I'm still hunting for some more bite. I currently have EBC red front pads/porterfield r-4s rears. 

Seems like pads are the big hindrance at the moment. The chassis has a couple options, Porterfield, Carbotec and G-Loc all offer the full suite of compounds. . 

Anyone had any suggestions for a good autocross pad that might see a track day or two?  









Papabishop Reader
9/18/18 7:30 p.m.

sorry can’t help with brake issues, but love the car. I had buddy years ago that had a similar green GT that always blew off hoses. Don’t miss helping holding hot hoses while he tightened everything back up. I have soft spot for earlier turbo cars that never got much attention! 

Ironsides Reader
3/12/19 7:04 p.m.
Papabishop said:

sorry can’t help with brake issues, but love the car. I had buddy years ago that had a similar green GT that always blew off hoses. Don’t miss helping holding hot hoses while he tightened everything back up. I have soft spot for earlier turbo cars that never got much attention! 



So, I haven't really touched the car since this past summer and it has been quietly hibernating in the garage.

After much back and forth with the suspension ideas, I felt like by the end of last season I was getting somewhere making improvements (driver mod helped a bit too) I have the right combo of sway bars (1" solid front, stock 18mm rear) and I feel like the more tire I stuff under it the better.

The next step in my mind was taking the plunge into doing the tedious measuring and calculations to determine spring rates and have the dampers valved to match. Fortunately, there have been 2 other folks that have done a great deal of figuring with the mazda GD chassis for autocross. I've been to go ahead and take their learnings, and insert my best assumption. 

Both gents prior have had good luck with 500# front and 550# rear, using the same formula, massive front bar and stock rear.

 At the moment, the car is currently 400# front and 275# rear, using the out of the box Ksport springs, which are widely known to be inconsistent and foster an unpredictable suspension response. Additionally, I assume not much, if any R&D was part of the process of selecting the out of the box rates, nevermind tailoring them to any particular function. 

I've opted to go with Swift metric springs, not only for ride quality and consistency but also to shave off a few lbs as they use a proprietary metallurgy. 

I'm hopeful this will provide the balance the car needs to remain tight and predicable on the slaloms, and keep the rear loose enough to rotate controllably. 

The shocks will be sent out to FEAL where they will be evaluated and revalved to handle the new selected rates, will also be interesting to see if the damper pistons need to be altered at all to accommodate better performance, time will tell!

Another thing that will help provide improvement will be corner balancing, I happened across a screaming deal on ebay for a set of older but basically new intercomp SW2 scales complete with storage case!



This past weekend prior to disassembling the car for damper removal, I tossed the car on to get an idea of where we currently were. 


The current overall was 2746lbs, and with the existing damper adjustment I was netting a 54% crossweight (50% is optimal)

So not too far off the mark! 

The scale will certainly come in handle when reinstalling the dampers and getting the car readjusted and aligned. 

Car is now up on jacks and dampers have been removed to ship.

The last add-on to compliment the suspension upgrades is a pair of camber caster plates. A small company actually made a nice set for the GE chassis (later model probe, mx6, 626 etc.) To fit the GD chassis, two of the strut mount holes will need to be slightly enlarged, so no major cutting or modification needed. These in theory should allow for the addition of 5-6 degrees of positive caster. 

The Ksport camber mounts currently are fixed and only allow 1 degree of positive caster, so this change will greatly improve the dynamic camber curve and provide a better steering feel! 








wheelsmithy SuperDork
3/13/19 5:49 p.m.

Good Stuff!


Tillerman New Reader
3/15/19 11:42 a.m.

Very good stuff - thanks for the update.

What shocks are they again?


Ironsides Reader
3/17/19 10:30 a.m.

The current struts are K-Sport Kontrol Pro, which is their entry level line of coilover dampers. 

The have adjustable compression settings. I've put about 10-12K miles on them and they have held up alright, just haven't been super please with the performance as I have grown driving the car.  


Ironsides Reader
3/25/19 8:10 p.m.

Scored some time in the garage this past weekend. 

Dampers made it to the west coast and FEAL tells me they should be ready in a week or two.

Springs have arrived as well, a bit lighter than the springs they are replacing which is a nice surprise. I'll try to get them on the scale to fine out exactly how much. 

Now, one thing to note, K-sport (D2 BC XYZ etc.) all use 62mm springs. I know BC has worked with Swift to offer select spring sizes and rates in the 62mm ID, likely to appeal to the stance crowd, however none would suit my needs.

I chose to go with a 65mm ID spring, thinking it would close enough, I was surprised how much slop the spring had on the perches. I Spoke with Mike at FEAL and he mentioned this should be fine as they use the same sizing on their 441's etc. (sigh of relief) 

K-Sport perch:

Swift 65mm ID coilover spring:

Also picked up a gently used set of A7's, date codes from 2017, look to have only been used once, and they were about 1/3 the price of new. Sizing is 225/45r17. I have a set of 17x8" wheels to mount them on. It will be nice to be on the proper tire for SCCA events for the class. 

With the spring sizing figured out, I made good progress with the top mount fitment. Now I mentioned the new plates were for a GE chassis, which uses a slightly smaller bolt spacing than the GD. Which requires enlarging of the stock strut mount holes ( Street prepared class legal) (good bye factory alignment ever again LOL)

I opted for these for ease of caster and camber adjustment, cost, and installation effort. My alternatives here were, pay 4x as much for ground control RX7 FC3S plates, which would then need to be machined for larger bolts anyway. or fabricate my own and have them machined. I pressed the somewhat easy button. 

New caster plates and old camber mounts side by side:

Bolt spacing difference:

Few minutes with the dremel, voila:

But not before I took an angle to my fancy new plates (sharp corners needed some clearancing from the tower):

Good to go, I may have short changed my self a few mm of camber adjustment. I can always mill the plates out a bit to get a hair more camber if needed. Should be enough to get me to at least -2/-3 degrees. 

So at this point we are all ready for the dampers to come back for reassembly and initial setup. 

Shifting over to "winter" project 2, wheel hop. 

I currently use AWR's front and rear trans mounts which are poly as noted in an earlier post. However, this leaves the side engine and trans mounts the 30 year old original rubber mounts. On launches, I have been getting a pretty atrocious amount of wheel hop, which surely isn't doing my gearbox or traction any favors. 

Current state of affairs, woof (can flex with my hands):

Solution, I had some energy poly bushings laying about, for the passenger side engine mount this is the cardboard engineering I came up with:

For the drivers trans mount, the plan is to burn out the stock rubber, plate the stock mount bracket and weld a tube into the middle to house the bushing, less cardboard needed. A friend of mine is going to cut me up some bracket parts on a CNC plasma table and we will hopefully get these welded up next weekend. 

With the heavy lifting done for the weekend I began the game of will it fit.

I'm currently running a 245/40 front tire on a 17x9 +25 and 225/45 rear on a 17x8 +35 for street tires (some local clubs diverge from scca classing)

I've been curious if I could cram the 245 out back and too my surprise, it looks like it may just fit. 

Trailing arm clearance: 

Since the front still has plenty of room, I'm tempted to try a 255/40 up front now and pick up another pair of wheels to match. would like to put the suspension back together before pulling the trigger just to get a final once over. We shall see.

Reasonably happy with the how this is progressing so far. 

With any luck it will be ready for the first event on April 20th!














Tillerman New Reader
3/28/19 8:30 a.m.

Great progress and literal cardboard engineering. I like it!

Ironsides Reader
4/6/19 5:57 p.m.

Built up the side engine/trans mounts. 


Began with a peace offering to the wheelhop gods...

With the old rubber and sleeve out of the way, I fit the metal bits I had cut, surprisingly they press fit in. Totally by accident, im not that good..

In the car for mockup and preliminary tacking (along with the bits for the passenger side engine mount: 

Fit up was great!

Finish welding action shot:

The finished mounts! Very pleased, shot a couple coats of primer on them and will hit them with some chassis paint when ready. Chock this project off the list.


Ironsides Reader
4/7/19 9:19 p.m.

Finished off the mounts today with some paint and final install. Pleased to put them to bed. 

Checked another item off the list, needed to relube the rear poly bushes in the lateral arms and trailing links. Figured I'd tackle while still waiting for the dampers to arrive with the suspension apart. 

Inner cam bolts unfortunately do not come out unless you drop the subframe, so down it goes. 

Contemplated painting the arms and subframe but I was worried removal of the bushings may risk damaging them,and whiteline has since discontinued them, so I scrubbed off the grime and lubed them up. 


Picked up some b stones a couple weeks ago, now fitting 245/40's square, stopped by my friends garage and mounted them and got the Matrix aligned. 


Hope to have the dampers this week and I can move on to final setup/corner balancing! 







Ironsides Reader
4/18/19 2:39 p.m.

Baby steps were made this past week. 

Dampers arrived back from FEAL, now valved for 9k front, 10k rear spring rates, sporting some fancy new front adjusters due to the need to replace the front shock shafts. 

I promptly got them setup with the new swift springs.


Here is where we hit a bit of a snag,  my previous eyeballing/measuring for tire fitment was close, but seems the 245/40 combo on the rear wheels is going to be  a hair too tight. 

I don't seem to have much, if any room on the inside due to body/wheel well/fuel filler neck interference under compression.

And about 3/4 of shock travel at  the ride height needed for proper roll centers leads to some tire contact with the body. (Sadface) 

I could likely pull the sheetmetal a bit, but that would also require heavy triming of the bumper and skirt moldings to prevent contact. Not sure I want to butcher the car up that much quite yet. 



On the other hand, I can get full travel out of the prior 225/45r17 I have on their currently. 

SO, seems I will continue on with the staggered wheel/tire setup for the time being. 

That said, the new dampers are now in place, took the time to paint my rear knuckles while everything was apart: 


New stock style trailing arms came in, I can confirm, they limit tire clearance 8-10mm at the tire, now street-prepared class legal and no chance for tire rub on these arms :) 


Also clearanced the strut tower bar mounts, as they were interfering with some stamped details on the front towers, leading them to not sit flat: 


Hope to have most things reassembled this coming week. 



Ironsides Reader
12/22/19 7:36 p.m.

Holiday revival post, never actually got to race the PGT this year, and missed Radwood Boston due to traveling for work(still salty)

My BRZ received ohlins, sways and STX rubber and ended up filling autocross duty  for the season.

Subaru/toyota really outdid themselved, man what a great car (uber cool retired SAC hanger in background):

The PGT still requirea a sit of fine tuning before a proper flogging.

Suspension has been reassembled and hoosiers are now mounted.  

Took it for a few spirited runs up and down the road, not rubbing on bumps and feels great, maybe it's okay? 

Been quite some time since I've driven the car, but the spring and damper upgrades feel fantastic. 

Rear tires still look really close, suppose I'll need to try them and bring some spares, this is the narrowest hoosier I can get in 17" so flares may be a necessity (using 12mm spacers in the rear to clear filler neck, this causes potential interference with rear arches after 2" of travel or so) 

The misses and I recently purchased our first house, with quite a bit of garage space. The probe will soon reside in the new space and I'm looking forward to widdling away at the to-do list without needing to travel 30mins. 


slowbird Dork
12/23/19 9:14 a.m.

I need to go back and read the whole thread...hnnnngh first-gen Probe...angular 80s goodness!

FordProbeGTGuy New Reader
9/3/21 9:19 p.m.

I like how you didn't give up on the probe even with the many challenges came up.  Still have it?


FordProbeGTGuy New Reader
10/4/21 2:00 p.m.

In reply to Ironsides :

You need to have a pcv valve before that catch can by the intake manifold otherwise your boosting into the can. Not good...  The valve is meant to close to keep pressure from entering the valve cover.

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