SPEEDY Z28

I'm sure someone will tell me to search but a simple yes or no would be appreciated. It says they are 4 pin relays with OFC wire. It says 30a/40a on it.

Also if someone could explain why it says 2 different numbers for the amp I'd appreciate it.

robguitargod1

iTrader: (4)

I'd go with a 5-pin relay. It will have an 87a pin that's normally closed to pin 30 (in it's non-energized state)

http://www.ebay.com/itm/5-NEW-12V-BOSCH-STYLE-AUTOMOTIVE-RELAYS-40A-30A-SPDT-WITH-SOCKETS-AND-HARNESS-/181777115405?pt=LH_DefaultDomain_0&hash=item2a52c2a90d

SPEEDY Z28

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SPEEDY Z28

OK I figured out how the 5 pin works, but can someone explain if the wiring and pins in the socket are safe to use?

Also why does it say 30a/40a and not one or the other?

Pocket

iTrader: (24)

4 or 5 pin doesnt matter for LSx conversions. I dont use 87a for any standard relay packs

30/40a means they send whatever relay they have in stock be it 30A rating or 40A rating. Beware the 40A relays require more current to kick on the 12v leg of the coil than the LSx PCM outputs. It works fine for PCM grounded coils, so FP will be inop, Fans and AC work fine. Wish theyd post the actual specs of the parts before I buy 500 of them but whatever

The wire they send is garbage but the terminals are fine, but you cant uncrimp them. Do an ebay search for relay terminals and compatible pins will show. I havent found the relay sockets by themselves so everyone I get, I have to depin

SPEEDY Z28

OK I'm a little confused. The relay it suggested on lt1swap.com was a 40a. This is my first LS Swap but I'm failing to see where the relays are PCM grounded(possibly because I don't have fan harness yet, but I don't see anywhere in th engine harness that would suggest it).

Also how do you know what terminals and wire you can use for the relays?

Pocket

iTrader: (24)

The amp rating is how much current the relay can handle without failing. More powerful electronics like bigger fans and fuel pumps draw increasing amounts of current so they require a higher rating. OEM 3rd/4th gen fans draw a max of 30A when kicking on so the lower rating will suffice. Walbro 255's are plenty of pump for 95% of builds on this entire site and still draw less than 30A at peak so you're fine again. If you went with an aero340 or A1000 pump, they draw quite a bit of current, so a larger relay is required. I had to use a 40A relay with 10ga wire for my 340 install. LT1swap is likely using a relay to power up a fuseblock in which case 40A is recommended for most. 12v will come from your IGN switch so plenty of current and ground will be in the harness

PCM control is simply which side of the coil, the PCM will control, either 12v or grd. Most relays are controlled on the ground side but the FP relay is on the 12v side. My comment about the 40A relays was that the current required to energize the internal coil of the relay was greater than the current the PCM sends so it is not compatible with the FP. Other relays such as fans and AC are activated via ground leg, so the 12v leg is based on a point in your fuseblock so the current is whatever the fuse that protects it. Well above any the PCM will output

Terminals are made to fit a connector body, so you're already limited in choices. Once you have the type of terminals to fit a connector, you need to match those with the wire size you'll use. To simplify the process use only 18ga and 12ga terminals. These universal relay packs use a 1/4" push to seat spade terminal. Various mfrs make them, so pick a pair for the wire sizes you need

Most new harnesses and most aftermarket use TXL 18ga for 95% of the harness and TXL 12ga for heavy current applications ie fans/fuel. Some OEM applications use 20-22ga TXL for very low current instances, Id avoid them to prevent having to calculate load vs length and use 18ga all around

3rd gens used GXL wire because TXL wasnt cost effective yet. TXL simply has a thinner insulating jacket than GXL, same ratings per size

Terminals
http://www.ebay.com/itm/PER-074-20-Terminals-For-Relay-Connector-Housing-10-12-Gauge-Wire-Clip-In-Spades/261376143437?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D32933%26meid%3D93eb6fcfdefd49eb9ca3b2d24f896c3b%26pid%3D100005%26rk%3D1%26rkt%3D2%26sd%3D331108584940http://www.ebay.com/itm/PER-073-20-Terminals-For-Relay-Connector-Housing-14-16-Gauge-Wire-Clip-In-Spades-/231137746736?hash=item35d0e21f30&vxp=mtr
Not sure why the smaller terminals say 14-16ga because I use them and neither size cable will fit in them. 18ga fits perfectly

In a nut shell, those are good for the money
If they send 40A relays, you'll need to find a 30A version for the FP ($5 at any parts store)
The wire they send is junk

scooter

iTrader: (11)

Here are sockets, and you can buy in small quantities if you need

http://www.waytekwire.com/products/1...rs&pageSize=36

SPEEDY Z28

Ok is it bad that I've been using spare wire out of another GM harness and been matching up the wire sizes to the same size they were?

I've been adding 3ft to every wire pretty much

Also I'm using the same fuse block as LT1swap because I'm a carb car. So do I need the the 40 amp for all or?

Pocket

iTrader: (24)

Thats fine

SPEEDY Z28

OK not trying to make you repeat things 15 times but even with the separate fuse block I still need a 30A relay for the fuel pump, correct?

Also, I don't know if I need it, but if I was to use a Walbro 285 would I need any bigger size wire or relay than a 255?

Pocket

iTrader: (24)

Yes, the PCM will still control the relay, so you have to run a 30A version. Not because the PCM cannot control 40A relays, but because the PCM cannot control that particular relay via stock orientation

Stock 14ga wiring is plenty for a single 255 when used NA. Theres only a 20A fuse protecting it so any relay bigger than 20A is overkill

mwfrels

This good stuff to know. For us non-sparky oriented folks a lot of time could be spent in diagnostic mode for a non-operational fuel pump.

M

SPEEDY Z28

OK one more question. What kind of aftermarket gauge will work with the 3 wire CTS? I'm not sure on how to find what I need to know

Pocket

iTrader: (24)

I had three customers each try to fire up a car the same day and all three had the same problem. Over the phone diagnostics... no me gusta

Any that follow the factory GM resistance range. If its not compatible, it will come with its own sender and they often stipulate they MUST be used with the supplied sender. Glowshift is an example
Common ones like autometer work fine with the 3 wire CTS in most cases

SPEEDY Z28

Would speedhut gauges work? What is factory resistance for the temp sender?

Also do you know what the vacuum line taped into the harness goes to?

I appreciate all the help. I've tried to search some of this but can't really find anything.

R13_Braz

I'm one of them lol. With my engine committing hari-kari, I haven't even messed with it again outside of running a straight power wire to the pump. But, reading this I'm going to go grab a 30 amp relay and see what happens as I KNOW it's getting voltage, and it makes sense it's not grounding properly if this is the case.