The Transition – backing away from full kill

After over a decade of serious competition that included one Kentucky Region SCCA CAM-T championship, five top-ten GTV finishes at Optima Search for the Ultimate Street Car qualifier events, two Optima Ultimate Street Car Invitationals and an amazing trip to Saudi Arabia, we blew both head gaskets in Vegas at the 2021 OUSCI. It’s time to relax.

There’s a couple of entertaining videos detailing the head gasket repairs up on Youtube:

Part 1:

Part 2:

Moving ahead, it’s clear that I’m an an inflection point when it comes to competition. I could keep running the Buick, but to keep up with the state of the art, the car would basically have to go under the knife. With the likes of Frank Trutanic’s amazing T-Type on the scene, the gauntlet has been thrown down. Competing in GTV or CAM with this car and staying relevant is going to take more time and treasure than I have. The car is a head-turner, it has reached a level of development that I would never had imagined it could, it garners respect everwhere it goes, but it’s got issues that just can’t be overcome within my budget and abilities. Foremost, it’s tire-limited, and the drivetrain just isn’t reliable when it comes to road course use. It works, but I pay dearly for it in the form of some variety of major overhaul work nearly annually. It’s time to pivot this car away from competition and back to just being a car.

So, the Buick is going back to a fast street cruiser. With the head gaskets fixed, we’re going to make a few tweaks to the car to maximize on-the-road comfort. Stopping multiple times from 140+ mph during a session at Road America is no longer necessary, so out go the track oriented brake pads. Lots of part throttle cruising and stoplight activity is coming, so we need to deal with the fuel heat problems created by the oversized fuel pump. We might want to drive somewhere and not have to stop every 150 miles to keep the tank from getting below a half a tank, so the low-tank fuel starve issues have to get fixed. Finally, we don’t need the car as low as it is. It’s raked pretty severely in an attempt to keep the nose on the ground at high speed (which worked), but it’s too low for street use. The air dams can scrape getting into parking lots, and steering angle is compromised by contact with the control arms and wheels at full lock.

So, we have a list. Let’s knock it out!

First, the brakes. The current rotors and pads have been on the car nearly three years. The EBC Brakes BlueStuff track pads provided reliable high speed, high temperature performance, and the rotors took a spectacular amount of abuse. But they were cooked and in need of replacement.

The completely cooked rear pads

I’m switching to EBC’s YellowStuff compound. Where the BlueStuff provided no need for a break-in and fantastic high-temp track performance, the YellowStuff will provide much better low-temperature braking, with enough heat tolerance to allow spirited street driving and maybe the occasional autocross or non-competition HPDE type track day. They also require a lengthy break-in (1000 miles!). Combined with new rotors and a brake fluid flush, these brakes are ready for years of street duty.

Fully assembled front brakes

The fuel heating problem? Many know, many more do not, but fluid passing through a system creates friction. When you do a thing like convert an old turbocharged car to E85, you need a very large fuel pump to move enough fuel to feed the engine at full throttle. But, at part throttle, idle, and cruise, it doesn’t use any more fuel than a typical economy car. It only takes ~20 horsepower to move a car down the highway at 60mph. If you have a setup where your pump is moving enough fuel to feed 500+ horsepower, the friction of all the fuel moving through the lines and back to the tank via the return adds up, and you get hot fuel. Hot fuel causes problems with your tune, reduces efficiency, and can lead to bad things like pre-igniton and knock. Taken to an extreme, you can actually boil the fuel in the tank, and that’s bad.

The OEMs solved this problem with return-less fuel systems. The fuel system simply dead-ends at the fuel rail, and they use a pulse width modulated pump controller to throttle the pump itself so it’s only pumping exactly the amount of fuel required for the injectors and to maintain the desired rail pressure. We can do something similar, even if we can’t be so precise as to go to a return-less system. The trick is to de-rate the pump when you don’t require full flow. A solid state relay wired in-line between the pump and the main pump relay, controlled via a pulse-width switched input on the ECM will allow me to run the pump at 60% flow when manifold pressure is below 100kpa. As soon as we exceed 100kpa, the ECM will ramp the pump up to 100% and we’ll get all the fuel the engine needs to pass that truck or hoon that back road. This should considerably reduce fuel temperatures. Amazingly, we have an available input on the ECM in the form of the old evap canister purge solenoid connection. A few metripack connectors and some wire and we’ve solved the fuel heat problem, and it’s nearly plug and play.

In addition to the relay, we’ve installed a Holley Hydramat pre-filter in place of the nylon sock. You can watch that install on the Youtubes here:

The Hydramat is cool stuff. Go check out Holley’s videos on the thing, also available on the Youtubes. With this in place, I can confidently run the car to nearly empty without worrying about fuel starvation.

And finally, front suspension. The QA1 springs we’ve been using are 600lb-in springs with a free height of 10″. What we found was they’re too soft and too short. Right now, the car is sitting too low in the front for street use, but we are nearly out of threads on the shock body, so raising it further is difficult. The solution is a 700lb-in spring with an 11″ free height. This will allow me to raise the nose an inch while moving the height adjuster closer to the middle of the shock body, and offer more control of the front end. I’ll also be able to adjust the dampers down. Right now they’re set full stiff in the front to try and augment the too-soft spring. This will actually increase comfort, despite the stiffer spring rate.

And then? Enjoy the car. I need to put 1000 miles on it to bed the brakes properly. Maybe a road trip or two this year? Stay tuned!

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