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 Back in a Formula Again 
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Post Re: Back in a Formula Again
That's super cool at the grad night!

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86 IROC
LQ4/T56/3.50 8.8 (next step..TC76)
Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.html
Formerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH


Wed Jul 05, 2017 11:23 pm
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Post Re: Back in a Formula Again
Well......looks like Photobucket has completely trashed this thread!

Guess I have a pile of editing to do. :evil:


Sun Jul 16, 2017 7:50 am
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OK....all the links have all been transferred over to Flickr......Photobucket can kiss my butt!

Oddly enough there is 1 post on page 10 that the site would not allow me to edit......anybody have any insight as to why that might be?


Sun Jul 30, 2017 8:47 am
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Post Re: Back in a Formula Again
Back when I first bought this car it had numerous brake issues that I documented early on in this build thread. To get the brakes functioning normally required a new master cylinder, new flex lines, & all 4 calipers were rebuilt. The existing pads and rotors appeared to be in relatively good condition so they remained & I have been driving with them since. Despite most of the braking system being new though, I would not describe the braking performance as "Good"..........."Adequate" would likely be a better description.......they stopped the car.

Fast forward a few years now & I got a Wholesale Closeout email from RockAuto in which I discovered new front brake pads for $8 and new rear pads for $7.....I decided to finally dig into the brakes to see where some improvements could be had. What could it hurt.....all new pads all around for $30 shipped to my door! After all, the existing parts would likely be upwards of 10 years old from what I know of the history of the car.......I really don't know if pads age and lose performance like a tire would for example, so to cover that base, and for the sake of $30, why not just replace the pads.

Now I decided to tackle the rears first for a couple of reasons. Driving the car gave me the impression not much was happening back there......that impression seemed to be backed up by the fact that, while I was constantly having to clean brake dust off my front wheels, the rears remained relatively clean.

So I set about resurfacing the rotors & popping the new pads in. After bedding the pads in, I did note an improvement, but it really wasn't anything to write home about. That's when I came across a thread on thirdgen.org that intrigued me.

https://www.thirdgen.org/forums/brakes/ ... grade.html

So I headed over to my local Acklands Grainger & ordered up some new springs for the proportioning valve.

Image20170803_114649 by Shane Hewitt, on Flickr

Now being the person I am, I wanted to devise a way to determine if the new spring actually made a difference other than "it feels better". What I decided to do was to drive around my block somewhat aggressive & measure the temps of my brake rotors immediately after rolling into my garage. With the OE spring installed my rotor temps were as follows.

Front rotors.

Image20170803_114358 by Shane Hewitt, on Flickr

Rear rotors.

Image20170803_114346 by Shane Hewitt, on Flickr
Image20170803_114340 by Shane Hewitt, on Flickr

Once that little test was completed I proceeded to swap the new spring in.

Image20170803_115414 by Shane Hewitt, on Flickr

New spring on top, old spring on bottom.....note the new spring has notably thicker coil wire.

After bleeding the system, I then went out to perform the same test. Upon returning to my garage, the front rotor temps remained essentially unchanged as I would have expected. My rear rotor temps changed though!!

Image20170803_130147 by Shane Hewitt, on Flickr
Image20170803_130128 by Shane Hewitt, on Flickr

The 30 deg increase in rear rotor temps would lead me to believe that the rears are working a little harder now! Given my test drive was only less than 3 minutes, its hard to say if there is a seat of the pants improvement or not.........I'll report back on that later once I have logged some more miles with this spring installed.

I also have 4 more springs out of the 5 pack available if this is something of interest to anybody else.


Thu Aug 03, 2017 3:58 pm
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Post Re: Back in a Formula Again
Got out for a nice hour long cruise yesterday so I thought I would post a follow up on how the proportioning valve spring is working out.

It would seem that the pads have bedded in better as my rotor temps have gone up a little more in the rear. Instead of the 60 degree difference front to back I initially saw after putting the spring in, I'm seeing about a 45-50 degree difference. So if the front rotors are at 195 - 200 degrees, I'll typically see 145-150 on the rears. Having said that, during regular cruising around, you can tell the rears are participating more in the fun now.

Towards the end of my drive I decided I should really do some hard braking to get a feel for how the brakes work now so I know what to expect if I really have to lay on them. So I went out to my "test facility" & got up to 130'ish km/hr and progressively braked harder and harder. Ultimately I got to the point where the rear tires were starting to howl warning of impending lock up before the fronts. :shock: At this point I'm hoping the front brakes pick up some power when I put the new pads on to balance the system out again as I really don't want the car to be tail happy under hard braking. Hopefully I'll get time to give the front brakes some love this week. On a positive note though, this is the first time the rear brakes have had the power to lock the tires up, & the brakes definitely whoa the car in a hurry now, so definitely a pretty significant upgrade.

So I would now upgrade my assessment of the car's braking performance from "adequate" to "pretty good". A little more power & initial bite from the front brakes would earn the car an "Excellent"......hopefully that will happen this week.


Last edited by auto_god on Mon Aug 07, 2017 7:57 am, edited 1 time in total.



Mon Aug 07, 2017 7:15 am
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Post Re: Back in a Formula Again
While I'm posting follow ups I should make note of a trait the car has picked up since installing the subframe connectors.

Before I installed the subframe connectors accelerating aggressively out of a corner (such as turning through an intersection) would of course twist the body some, unloading the inside tire causing a nice progressive drift around the corner. Since installing the subframe connectors, the body twist has been pretty much eliminated keeping both back tires planted. This has made the grip level notably higher exiting corners, however the downside is once you get to that limit, the car is far less progressive now. Instead of a nice progressive, controllable drift, the car now has a tendency to snap loose.......so higher overall grip level, less forgiving when you get there. Now that I know what the car is going to do & am expecting it, its lots of fun, but the first time it snapped loose on me it elevated my heart rate a bit! :shock:


Mon Aug 07, 2017 7:53 am
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Post Re: Back in a Formula Again
Mid summer last year this happened.

Image20170815_194852 by Shane Hewitt, on Flickr

I've been on the lookout for a suitable replacement since. Here we are a year later & I finally found one in good enough condition & a close enough colour match (note the center portion of the base of the seat has a slightly darker shade of grey to it). While the colour is slightly off and I'm sure it will fade some, the slight colour mismatch offends my eye less than the giant rip in the old seat !!

Image20170815_194840 by Shane Hewitt, on Flickr

One thing to note about this swap though. When I was searching for a replacement seat, I read on thirdgen.org that the seat bases are interchangeable from side to side, so this seat is actually a passenger side seat from the car it came out of. Obviously from the picture the swap from passenger side to drivers side can be made to work, but in this case it was not a direct bolt in. The 2 bolts on the outboard side that secure the seatback to the base went in fine....I was able to locate the appropriate holes under the fabric and run them in without issue. The inboard side however (by the console) has a Torx bolt to secure the back to the base. I did have to drill and tap a hole for this fastener slightly ahead of the existing hole in the base. This actually had a surprise benefit. Previously whenever I would drive the car I had a bit of a gangsta lean going on......the seat had a bit of a lean towards the center of the car. Because I had to drill and tap a new hole for the Torx bolt on that side and it having to be located slightly ahead of the existing hole (less than and inch at most), the net effect is that I now sit straight!! If you were to look REALLY close at it you would see that the seat back is not 100% straight in relation to the base, but to the casual observer, its not noticeable...........the rip in the old seat was IMMEDIATELY noticeable.

So I'm satisfied for now. I may still keep watching for the correct seat, but in the mean time I now have a much more comfortable seat with no rips.....and sit straight in my car!


Wed Aug 16, 2017 8:11 am
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Post Re: Back in a Formula Again
So several years ago when I first put this car on the road it had a ticking noise that fluctuated in loudness with how much I was on the gas. It would put you in mind of a header leak, and I spent the first summer trying to isolate the noise without success. The car drove well, and after a while I eventually didn't notice it when driving the car. That winter I put my Lunati cam in, set the valve lash to 0 lash plus half a turn.......got the car out the following spring, car drove well, made good power, noise was unchanged. Last winter I put my ported heads on, same routine setting the lash......0 lash plus half a turn. Car now made great power, drove well, noise was unchanged.

Since I put the cam in, the car also developed a mild misfire........you could tell it was not just cam lope at idle. Driving around it was imperceptible, but looking at the data I'm constantly recording, it was quite visible in the o2 waveform too. (misfire events circled in red)

ImageLash too tight by Shane Hewitt, on Flickr

Given that the car drove so well I didn't worry about it too much, but next summer is going to involve passing an emission test again, so I've been focusing on resolving these issues, making sure my ignition system is in top notch condition, going through my tune with a fine tooth comb.

Fast forward to the past couple weeks since I brought home my spare motor I've been fiddling around with. The person I bought it from told me the van it was pulled from sat in a field for 2 years before the motor was liberated from it. As I mentioned in my other thread about that motor, the lifters were all stuck solid........the thought went through my mind that the Formula sat in the previous owners garage for over 5 years.........hmmmmmm. If the lifters were in fact stuck and not just pumped up as I assumed when I put them back in the motor, adjusting them to 0 lash plus half a turn would actually have them too tight, likely causing the valves associated with the stuck lifter to be hung open probably .020"........that would definitely cause mild misfires, that would definitely cause an audible ticking through the headers that would fluctuate with engine load.

In order to test this theory, I popped the valve cover off the drivers side bank (the bank that has the o2 sensor on it) and backed the lash off a quarter turn to see if matters improved. On one hand I really wanted to get to the bottom of this issue, on the other hand I was hoping matters didn't improve as this would mean the intake manifold coming off to remove the lifters again this winter.

I plugged in TunerPro & went for a drive........

ImageLash backed off by Shane Hewitt, on Flickr

Misfires on bank 1 pretty much gone......DAMN IT!!!!

Based on that I pulled the valve cover off bank 2 and backed the lash off and went for a drive......ticking noise has virtually vanished. Idle has settled way down (actually sounded cooler before!). So I guess my manifold will be coming off AGAIN this winter to pull the lifters out for rebuild, but the upside is the ticking noise should finally be gone, should make even more power, & hopefully make passing emissions far more likely.


Wed Oct 18, 2017 9:05 pm
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