thewird

iTrader: (8)

For the guys running high boost, rewire your damn fuel pumps with 10 gauge wire from the battery all the way inside the tank to the fuel pump itself and a 40 amp relay. If your running a Supra pump, you need to run a 60 amp relay or double up your 40 amp relay to make it reliable after prolonged running (im not kidding). Tired of having to repeat myself with every car and getting the response "can't you just tune it as is".

And stop using crappy *** Princess Auto electrical tape in the engine bay, it can't take heat for ****. Even the Crappy Tire electrical tape is better then the Princess one.

Side note, turbo's love the cold but boost can increase on its own so watch your boost gauges.

thewird

Buggy

iTrader: (8)

I'd have to agree here. I don't run a high boost car, but even on any car sloppy electrical work is a real problem. If you're going to spend money on a car don't cheap out on a roll of wire, electrical tape, or other electrical supplies. Heat shrink and solder your connections or use some sort of heat shrink butt connectors. You'll drive yourself (or your mechanic ) crazy trying to figure out a problem caused by sloppy electrical work. Rewiring a fuel pump circuit when you've upgraded the fuel pump is always a good idea. The factory circuits where designed to operate the factory pump and that's it! Sometimes the factory circuits won't even do that well....

R.P.M.

iTrader: (3)

You said it best in another thread:



^ The Truth ^

2Fierce

iTrader: (7)

>< guilty.

HiWire

Not sure if my car qualifies as high boost.

Andoru

Agreed!!!

sctRota

iTrader: (2)

The second you start shortcuting things on rotaries,closer you get to the rebuilding path.

got_boost

iTrader: (16)

even if people are not running high boost. this should be a pretty popular reliability mod.
considering the low cost of doing this, how easy it is to do and how usuful it is.

its better to do prevention than to heal !!!

Terrh

iTrader: (7)

im running two supra fuel pumps off of one 40A relay....

I think they only pull about 10A each....

thewird

iTrader: (8)

What fuel pressure are you running? I've had a single supra pump pop a 20amp fuse starting from a stop light (ie, no boost). Also, if its not a rotary doesn't count, pistons dont need fuel LOL.

Go for a long drive and feel the relay after you come back (even if your just cruising).

thewird

Terrh

iTrader: (7)

40psi base so never more than 70psi.

I've never felt the relay or even thought about it until this thread.

The stock wiring is so wimpy that I figured I had things covered between rewiring it (I'm running 8ga to the relay, and 10 between the relay and each pump). I'll have to see if it's heating up when I go get groceries this evening.

I've had 99 fuel pump problems with my car this summer, but electricity hasn't been one. I think I've been in the fuel tank at least two dozen times fixing lines or other crap. It's hard to find proper 1/2" in-tank fuel hose, but -8AN braided stainless seems to be holding up.

On the electrical tape note - industrial/electrical supply places usually have far better tape and it costs less money than CT and PA junk.

thewird

iTrader: (8)

I also used -8 steel braided hose in tank for my pickup for the A1000.I even put a 90' fitting at the bottom LOL.

Here is an amperage draw someone did on a few fuel pumps. The Denso pump is the Supra pump, look at the amperage draw on that sucker. Also, comparing the Walbro you can see why people get away with stock wiring so often as long as you stay within the limits of the fuel pump, it barely uses any amperage.



thewird

Aaron Cake

iTrader: (1)

Yeah, this thread is a week old, but...I think it's a good rant.


Does a Supra pump really draw 60A?! That being the case, why would anyone ever use one? There are higher flowing pumps on the market that pull far more reasonable currents. My Aeromotive "700 HP EFI" pump pulls about 15A making about 60 PSI at WOT. Easily handled by 12 AWG wire and a quality 30A automotive (actually I think I have a 40A relay installed) relay.

Note that doubling up relays doesn't double the amount of current they can handle. The majority of the current is still going to flow through the relay contacts with the lowest resistance. And since both relays do not switch at exactly the same time, one relay will handle the startup surge alone.

3M makes a great harness wrapping tape. Can't remember the name at the moment though. Super something or other. Rated for temperature and hydrocarbon exposure.

Or set overboost cut in the ECU? Typically when I tune a car (which is rare...see my rant below) I'll tune to about 2 - 3 PSI past regular boost and then set the boost just above the normal boost level. May need to be adjusted a little once everything is set up but it's the safest way to go.

OK, my rant is...

The reason I don't tune other people's cars?! Because the times that I have, I'm sick of spending the 1st half of the day fixing problems! VR sensor wires backwards, wiring everywhere, fluids leaking, stripped oxygen sensor bungs, no wideband ("Can't you just read the plugs?"), etc. And all while I've driven out to some who knows where, so it's not like there are tools and equipment available to fix.

Then we have the non-local "rent a tuners". This is something I've never understood. When a tuner is brought in from 1000 miles away and tunes 10 cars in a weekend. HUH?! Anyone can tune a car at wide open throttle. It's the easiest and quickest part of the tune especially for turbo rotarys. The rest of of the tune is what makes the car actually drivable. How does Mr. Rent A Tuner tune drivability when it can take two solid days just to lay the ground work?! And then there's cold start, temperature compensation and all those little things that make a car actually livable. It can take weeks to set up all the temperature maps when the conditions are ideal (late fall) yet at that time, Rent A Tuner has long since flown home.

thewird

iTrader: (8)

The Supra pump doesn't draw anywhere close to 60 amps. The actual amperage draw is listed above in the fuel pump testing, about 16-17 amps on a turbo car. The issues is the relays can't sustain they're rated amperage without getting hot which then increases resistance, which leads to voltage dropping, which leads to fuel pressure dropping, which leads to your motor running lean. Your standard 30/40 relay WILL get hot on a Supra pump when boosting. I've recently tested an Aeromotive 340 on a car that was making somewhere between 370-400 rwhp and the relay got little warm but not hot after a sustained hour of driving/tuning. Much better then the Supra pump at least but I'd be concerned for someone trying to pump 500 rwhp on a single relay with it.

To be honest I never tested it and assumed it would aid the problem. Even if the majority of current goes through one relay, when that one relay gets hot and resistance goes up, would it then not start flowing through the other one? Basically it would be self balancing by resistance as they get hot. At least that how I imagine it LOL. Would appreciate anyones thoughts on this.


Yah, I always set an overboost fuel cut for the cars I tune but I ment it as a general statement for everyone

That is basically my reply when someone asks me how I compare to Steve. Steve is a very good tuner that is well rounded in a variety of applications, I have nothing bad to say about him. However, there is only so much you can do in a few hours on a dyno. Sometimes people get confused when I say they need to drop the car off for a few days. There even more confused when I start telling them the work done to their car is wrong or could have led to serious issues if not delt with and get the reply "but it runs fine". Yah, they run best before they blow up. Power tuning is always the very last step and usually only takes an hour or two (if nothing is wrong), and agreed it is the easiest part of tuning.

thewird

Terrh

iTrader: (7)

oh man do I wish I could finish tuning a car in a day. Actually, with N/A stuff sometimes it's possible, I don't think I have more than a day into my miata tune. Then again, I never did get around to making it start in the winter because it wasn't winter when i tuned it.....


even WOT tuning changes based on temp and etc, if the temp curves in the EMS aren't right or if you have a crappy air temp sensor (the skyline one is AWFUL for heat soak) then a "perfect" tune in the summer is perfect for ruining the engine at full throttle in the cold.

The thing I have the hardest time explaining to people is how much power tuning is worth. yeah, your car might "run fine" but if it was tuned to optimum it might have 50 more horsepower. Or more than that in some cases.


Dynos are still nice for doing WOT tuning, especially with the stunting law. But even without, it's a pain in the *** to watch 3 different gauges and see what's going on down the road all at the same time.

Aaron Cake

iTrader: (1)

I think the problem is more the crappy relay sockets at most auto parts stores than it is the relays. Princess Auto relay sockets suck for anything more than a few amps. Very little copper in those wires and very poor crimping to the terminals, meaning lots of heat at the terminals. Time and time again I've seen them melt the plastic on the relay surrounding the terminals. I even inadvertently used one on my fuel pump many years ago and had to replace it about 3 years ago because the wires were melting around the socket. Got me some Bosch branded everything and there's easily twice the copper in the wires and terminals, not to mention the terminals have an extra contact point.

Unfortunately this is stuff most people don't think about. They just don't know, or don't have the experience. And a good relay socket costs $20, as opposed to the $5 at Princess Auto for both the socket and relay.

Speaking from an electronics background, parallel relays are rarely used in real life because they act like extremely low value parallel resistors. In doing so they don't share load easily, so the relay with the majority of the current fails, then the other relay fails because it now has to handle everything. They don't really reach equilibrium. Of course the resistance of a set of relay contacts is very low, so the only way to measure it is to use a fairly high voltage (50V or so) through them and then measure voltage drop, from which you can calculate resistance...(R=V/I) . When parallel relays are used they are generally housed within the same case, pulled in by the same solenoid and have high quality contacts (mercury wetted with magnetic blowouts). Quite expensive.

Exactly! When someone asks me to tune a car, I usually tell them I'll need the car for a 9 days...two weekends and a week. And I'll only make claims that it starts and idles well cold in the temperature ranges that we experience during that 9 days. I can make my best guess on the warmup tables, but it's still just an experienced guess. Of course then they need to be in the car so I can adjust closed loop settings to their driving style, etc. A few runs on the dyno are great for that bragging HP number bu then the world changes when that car is put into daily driver duty and the owner is stuck in the parking lot at work at 7PM on a cool fall evening with a car that won't start because the cranking map is too lean.

On the rare occasion when I'll actually tune a car (only when I've overseen the build, though not necessarily participated) I'll usually tune the idle and some basic drivability, then tune boost roughly to keep the owner happy, then back to drivability, then refine boost. Keeps it from being boring.

Exactly why non-local Rent A Tuners are a concern. They make all the dyno runs in July while people surround the dyno (ever seen a turbo explode at WOT? I'll never stand around a dyno) and cheer, then the owner merges onto the 401 in October and wonders why the car idles funny when he arrives at his destination. And then it cranks lopsided the next time he tries to start up. No one is going to call Mr. Rent A Tuner back every time the temperature changes. That's where an experienced local tuner can do the job, with enough knowledge to make a good guess on the temperature tables to keep the engine safe (though not necessarily making optimum power without a real tune). At the very least it's amazing how many cars I've seen by "world class" tuners that don't have boost cut set. Or take 20 seconds of cranking to start up.

Well, turbo engines still make good power in the 10s AFR wise, so I think most people consider the car tuned at that point. But the difference between 10.5 and 11.5 is easily 50% more power, plus the car doesn't feel like a lag machine as the engine struggles to spool the turbo through that mess of fuel. Funny though how many maps I see with a 45 degree line through the table denoting how the car was tuned at WOT. No other changes in the load area of the map, so it falls flat on it's face when not drivin in that line. Convincing owners that those other areas of the map need to be touched can be hard as well. Can't even remember how many times I've heard "But I never floor it at 2000 RPM!". Yeah, well what about when you do? You're in the wrong gear and hit the gas...then the car can either ramp up into boost or die in a puff of black smoke. Your choice.

Data logging. Which is why I'm not enjoying my Microtech for one man tuning...Datalogging on it is about as much use as genitals on a parking meter.

thewird

iTrader: (8)

I never use the sockets and plug straight into the relay instead since all those premade connectors have garbage wiring gauge. Even the pricy one from Napa is only 12 or 14 gauge. Guess my easy solution of using 2 cheap relays is out of the window. So I'll keep telling people to go find a 60 amp relay online if they have Supra pumps or switch to an Aeromotive 340 which isn't as amp hungry. The Walbro 400 seems like a good choice but I can't see myself recommending it until its been out there for a while with no issues.

thewird

thewird

iTrader: (8)

Side rant that doesn't deserve its own thread. I tuned only 1 car this year @ 23 PSi aside from Jimmy's car. That makes me sad inside lol. Maybe next year Toronto will step up.

thewird

Lucas FC

iTrader: (1)

I just got my walbro 255 and fuel system in the mail. I need to rewire the fuel pump for my haltech anyway. The walbro came with the intank wires and wire plug that go from the pump to the tanks cover plate that the pump is mounted on. My question is can I use this and just use thicker gauge wire for everything else or does it fall into your rant of insufficient wiring?

ItsFun

iTrader: (25)

If everything goes well you could be tuning my project to something in the low 20s psi next summer

thewird

iTrader: (8)

Well for starters I wouldn't have used a Walbro but if your power goals are modest (sub 350 rwhp), its probably fine. The Walbro's don't draw as much amperage but if you plan to push it, I'd still go straight to the pump with the heavier gauge wire.

thewird

$lacker

iTrader: (9)

What's a good Canadian source for a quality relay and harness?

Aaron Cake

iTrader: (1)

Most auto parts stores sell the good stuff if you ask. Electronics stores can order relays and sockets of course. I tend to just stock up when I order from WayTek Wiring about once every year or so.

$lacker

iTrader: (9)

ie Canadian Tire, NAPA, etc? Or specialized places?
Anyone got a good online source? It's always nice to be able to click a couple times and have the thing I want show up at my door

Aaron Cake

iTrader: (1)

Welcome to Waytek

Auto parts stores like APC (my favourite), NAPA, etc. It just may not be on the shelf, or the ones on the shelf may be the cheap stuff.