Sleeper build thread

Ok guys, despite not having taken any pictures yet or not being officially started on this round of upgrades, I thought I would go ahead and start this thread to introduce you to my car, and what my plans are for it and to seek advice/input. I have a 1998 Park Avenue Ultra that I bought a couple years ago just as a fun beater to drive around. At the time, I thought, "hey, this thing is just going to be a comfortable driver that will be quick enough I won't have to mess with. I am NOT going to mod this car". Thousands of dollars of mods and custom fabrication later and I'm still hungry for a lot more...so fast forward to today and I'll hit on the main points of my mods.

At this point, a summary of my current mods are as follows: I have the car running on straight methanol with 1250cc injectors, and basically within 5% of maxxing them out at WOT, so I estimate around 500 crank hp based on my fuel consumption (less the 100 or so it probably takes to spin that blower that fast, not to mention the alternator and all drivetrain losses). Obviously custom fuel rails, and two intank 340lph pumps. AEM peak and hold injector driver running my methanol rated injectors. It's a gen V m90 car with an 8-rib conversion, 2.55" pulley overdriven 5% at the crank...northstar throttle body, water/meth injection, propane bottle plumbed in for cold-starting. It's intercooled and I'm probably the only Park Avenue in the world with rear A/C...I have a homemade trunk-mounted intercooler reservoir that contains a Suburban rear evaporator core for chilling my intercooler water (which works better than I ever anticipated). I run my ignition coils on 24V from a boost converter, and just recently as an experiment have gone to 3 ignition modules in parallel to drive them (turns out the current limiter in the ignition modules is by far the weak link in these ignition systems). I am looking to upgrade to 6 IGN-1 coils when I burn the stock ones up, but I have been unable to get them to crap out so far. Stock engine out of an 04 GTP, front power log, stock crossover and rear, 3" exhaust all the way back. Absolutely stock heads...everyone says I'm crazy, but it idles, runs and drives exactly like stock until you mash the throttle and I want to keep it that way. I may get ported heads, but I will not be camming this car. Ever. EVER. That's probably about it for power mods, obviously traction is an issue, so on to the traction mods...well not so much traction, because I really don't want to blow up the trans...more just curing the wheel hop was my goal.

Wheel hop is an enormous problem in this car...more than most of you can imagine. It's such a HEAVY car with such soft suspension that even at very light throttle I would frequently get violent wheel hop. In my quest for eliminating the dreaded wheel hop and getting some traction I have spent a lot of time and money on stuff that ended up not helping a lick (but I still feel better having most of these mods as insurance). At the end of it all, I finally found what did the trick, but I'll start with what didn't. The first thing I did was homemade strut tower braces. That did seem to help a lot early on, but as I kept modding and increasing my power my wheel hop returned with a vengeance. Next, I mounted some bigass Mustang wheels up front with 315mm Nitto Nt05r drag radials...if anything, that made the wheel hop less prone to happening, but much more violent when it did. Next, I thought maybe my control arm bushings were flexing too much, so I added homemade "traction bars" that I manufactured from tractor top links to basically preload the control arms effectively locking them in place by adding a third solid bushing. I was really excited about this mod and was sure it would cure my problems, but this did not help AT ALL. This made me crazy...I became determined to find the cause and correct it. As a result, the front strut tower brace ended up turning into basically a full upper engine cage so that I could add solid dogbone mounts up front. Again, I was sure this would fix it by eliminating engine movement...again, very slight improvement at best...and again, if anything the wheel hop just felt more violent when it did happen. What finally did the trick, is I have added a homemade front suspension preloading/limit system.

It's crude, but it works amazingly well...I just get clean wheelspin now, no hop whatsoever. Basically, I ran aircraft cable around the struts and up through the strut mounts on each side. I preload my suspension by tightening the two sides to each other so that the preload would be the same on each side. Right now it's fixed at almost stock ride height (maybe 1/2" drop)...but I plan on making the system cabin-adjustable with a winch at some point in the near future. It's really a pretty slick setup because I effectively have almost stock ride comfort, but with zero rise in the front end on acceleration. Once I get it setup so that it's quickly adjustable, I will be able to have literally 100% cushy buick ride when cruising around and within a few seconds, crank the preload up and be in race mode. Trans is still stock...just a shift kit and a ZZP converter, want to get a LSD, but more on that in a minute.

From this point, I'm looking to take the next big step, which I believe is a turbo. I've always wanted to mess around with twincharging, so it will probably at least start out that way, I may rework it later on if it doesn't work well. Other possible mods: m112 conversion (mostly because I REALLY like the cobra intercoolers...7x the surface area of my current heater core intercooler). I think the bigger blower would work a lot better in a twincharged setup than the M90. The intercooler is 2" thicker than my current setup (which grazes my hood head shield in places already), but I have some ideas for that. Definitely on the build list is a 4t80e transmission conversion with a LSD. I know the little 65e isn't going to take much more power, especially if I get some traction. I also looked into doing an AWD setup with versatrak parts, but after crawling around under one of those AWD vans, I don't think there's any way those parts will stand up to any kind of power at all (plus it would be a huge pain to do...requiring quite a body lift for clearance), so I decided to go the 4t80e route instead.

I have a pusher nitrous/propane setup that I started collection parts for that may or may not eventually go on the car. I am going to regulate the bottle pressures from the same high pressure source to guarantee consistent, tuneable results. That makes for REALLY small jetting on the propane side and really large jetting on the nitrous side, but I think it would be a very consistent system and the benefits of using propane are many.
1. My fuel system is tapped out already.
2. It will contribute to charge cooling since it boils at -44F
3. It's high octane
4. Atomization will be excellent since it will boil to vapor immediately
5. I can put it in a nitrous bottle and regulate them from the same push source to ensure the bottle pressures are always identical resulting in dead-reliably consistent flow and therefore AFR.
6. It results in a system with no permanent connections to the vehicle apart from the nozzle itself.

I will post some pictures of my setup and more details for anyone that's interested. I appreciate any and all comments or advice, positive or negative, especially regarding the direction I go with the build going forward. It's all up in the air at this point, I have various parts and pieces but am not committed to going any particular route yet. Thanks for reading, I know I can get wordy and talk in circles.
 
I feel like a 2.55 pulley on a gen v through a stock rear exhaust manifold and a power log up front probably isn't the best....

I have the cylinder fueling skewed to equalize EGTs bank to bank if that's what you mean. If you mean that's just way too much boost or way too much heat, I can tell you that it's not. Everybody always hates on my tiny pulley, but the car definitely makes better power (and earlier power) on a 2.55 than it did on a 2.8 or 3.0 (and it's had them all). It also keeps gobbling up more and more air all the way up to my 6000rpm shift so I don't see the blower getting particularly inefficient up top like everyone claims. I think it's all in the intercooling/thermal management. If I could find an even smaller pulley, I'd definitely run it.

Granted, I do have an insane amount of thermal management from squirting in approximately 3 times as much liquid as a gasoline car (2.3x as much methanol as it would take gasoline, plus around 24% by volume water to cool/ help seal up the rotors). Not to mention the intercooler that maintains probably 50 degree F or less temps throughout a pull. I have a 10 gallon reservoir, and it takes my intercooler pump a good 30 seconds to even pump that volume so my intercooler pretty much stays the same temp throughout a whole WOT pull. The A/C chilled reservoir was by far the single best mod I've ever done. A lot of work, and very expensive, but awesome. I will probably downsize the reservoir at some point, as I think a 5 gallon one would be plenty.
 
Hahaha I kind of figured. Were you on 3800pro?

I've lurked all over the place. This car has never been introduced on the internet...it's debut is here. I'm not particularly proud of how my work looks most of the time (if it's functional I don't give a rat's ass what it looks like) so I don't go attention whoring much. Plus, what's the point of a sleeper if everyone knows about it?
 
Ok guys, kinda lame, I know...but the only pic I have on my new phone is one where I was testing how much of a gap the coils would fire with a single ignition module vs multiple in parallel. You can see a small part of my strut tower brace/upper engine cage, and you can see the aircraft cable that ties my front struts together to preload them.

In case anyone was wondering, that spark is on the stock waste spark coils with two ignition modules. I'm currently running 3. ;)

unnamed.jpg
 
My engine bay is always a mess because I'm always working on something or other. And like I said before, I don't necessarily try to make anything pretty, so long as it works...so please excuse the sloppiness of some of my work, it's usually a work in progress or a test fit, to be tidied up later. Just to the right of the spark plug you can also see one of the valves I put inline in my A/C system to shut off the front evaporator core when I'm really wanting to chill the intercooler reservoir.
 
i want to know more about the "cables holding your strut towers together!"

I basically wrapped a piece of aircraft cable around the bottom spring perch on each of my struts and crimped it and then ran a loop of it up through where the alignment dowels were (I knocked them out of the struts). I used a ratchet strap to pull the two loops towards each other and then crimped a loop of aircraft cable around the two. It's currently not an adjustable setup, but was more of a proof of concept. I have something in the works to correct that.

If you do a google search for limit straps, a lot of the honda and dsm guys run them. That is basically what I was trying to replicate, except that I took it a step further and tied the two sides together so that the preload would always be the same, and so that it would be relatively easily adjustable. The basic function is to keep the front suspension from unloading, and keep the front end from rising when you accelerate. It may look kind of ghetto...heck, it may BE kind of ghetto...but it works and works well.
 
I basically wrapped a piece of aircraft cable around the bottom spring perch on each of my struts and crimped it and then ran a loop of it up through where the alignment dowels were (I knocked them out of the struts). I used a ratchet strap to pull the two loops towards each other and then crimped a loop of aircraft cable around the two. It's currently not an adjustable setup, but was more of a proof of concept. I have something in the works to correct that.

If you do a google search for limit straps, a lot of the honda and dsm guys run them. That is basically what I was trying to replicate, except that I took it a step further and tied the two sides together so that the preload would always be the same, and so that it would be relatively easily adjustable. The basic function is to keep the front suspension from unloading, and keep the front end from rising when you accelerate. It may look kind of ghetto...heck, it may BE kind of ghetto...but it works and works well.

That's some Nascar shit right there...
 

1quick

TCG Elite Member
TCG Premium
Jan 29, 2008
26,554
24,015
coal city
Ok guys, kinda lame, I know...but the only pic I have on my new phone is one where I was testing how much of a gap the coils would fire with a single ignition module vs multiple in parallel. You can see a small part of my strut tower brace/upper engine cage, and you can see the aircraft cable that ties my front struts together to preload them.

In case anyone was wondering, that spark is on the stock waste spark coils with two ignition modules. I'm currently running 3. ;)

unnamed.jpg

details on running more than one ignition module?
 

Thread Info