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Discussion Starter · #1 ·
I have maxed out my stock pump and I am not going for huge HP, so either one of these pump upgrades should meet my needs. I found tons of stuff on performance and cost comparisons, but which one is easier to put in? Basically if the MKIV Denso just plugs in without any modification I will probably go with that. If you have to rig up the mounting and splice in connectors or wires for the MKIV then I will probably to go with the Walbro that can be bought as a kit with the crap you need to put it in for a fraction of the cost.
Thanks,
Aaron
 

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the hardest part of installing a new pump is the removal of the tank. They are both easy to install, though the walbro requires cutting and crimping of two wires. Is having a plug-and-play pump (denso) worth the extra $125 for the pump (performance differences aside of course)?
 

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Discussion Starter · #4 ·
the hardest part of installing a new pump is the removal of the tank. They are both easy to install, though the walbro requires cutting and crimping of two wires. Is having a plug-and-play pump (denso) worth the extra $125 for the pump (performance differences aside of course)?
Hey Adam nice to see you are still around! Yeah I know the extra money seems hard to justify. I don't like messing with the wires just in case I want to put stock parts on the car, and I like the reliability of the Denso products. Plus I like the fact that the Denso was designed to work on a system with the high/low voltage setting from the pump relay. I don't know how well the Walbro works on the low voltage setting and I don't want to set up the car to run full voltage to the pump all of the time. I'm leaning towards the Denso if I can find one for a decent price.
Thanks,
Aaron
 

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Discussion Starter · #5 ·
gte the mk4 denso pump...
1 known to last longer
2 has more output than the walbro

mk4 hands down... i have installed them on alot of mk3 never had a problem
Thx for the input. I think that is the way I am headed. If you know guys the pn you are using that goes in without any re-wiring let me know.
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Aaron
 

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Hey Adam nice to see you are still around! Yeah I know the extra money seems hard to justify. I don't like messing with the wires just in case I want to put stock parts on the car, and I like the reliability of the Denso products. Plus I like the fact that the Denso was designed to work on a system with the high/low voltage setting from the pump relay. I don't know how well the Walbro works on the low voltage setting and I don't want to set up the car to run full voltage to the pump all of the time. I'm leaning towards the Denso if I can find one for a decent price.
Thanks,
Aaron
Yep, still kickin.

With the denso, you're getting oem reliability, which is tough to beat. I've got a walbro as, at the time, cost was a major deciding factor.

As far as the pump goes, the denso will pull significantly more current, so upgrade of your wiring is a good idea (see the link for current comparisons).
http://www.roadraceengineering.com/fuelpumpflowrates.htm

Also, the resistor will be a bit too big for the upgraded pumps and drop the voltage well below the desired 9V at low speed with the upgraded pump. To get around this, you can either source a new resistor or run the pump at 12V all the time (I'm doing the latter).
 

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Discussion Starter · #7 ·
Wow I am really surprised by current draw quoted on the Denso pump. Is that data correct? It is hard to imagine the Denso needing to draw almost 2X the current for the same flow as the Walbro. I guess I will dig through my MKIV manuals and see if that makes sense. If that is really true then I will probably change my mind and go with the Walbro. I think I might use the money I save to check with Curt at Elmhurst and see how much a new pump hanger assebmly costs. I went to the junk yard to check out a supra to practice on, and the lines on the pump housing were damn near rusted through. I am guessing mine are no better. Also, after looking at things, how high do you need to get the car off the ground to get the tank out? I am worried my jack stands won't be enough. Also toyota shop manual is sketchy at best for getting the tank out... just a picture of the parts and no directions.
 

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If your own hanger is a little mangled, here is a relatively easy fix. All I did was buy a -6 to 3/8NPT steel elbow, tap the hanger (after removing the stock supply line), screw it in, and braze in the line from the pump to the hanger (hint: drill out the NPT side of the elbow for the OD of the supply line - makes brazing extremely easy).


As far as dropping the tank is concerned, the key is to make sure it is empty. Aside from that, you need to disconnect the lines, disconnect the electrical connections from inside the car, unscrew the fill tube holder at the fuel door, and unbolt the straps (penetrating oil is your friend here for rusted bolts). Jackstands get the car high enough off the ground as well.

Hope this helps,

Adam
 

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Aaron you need to join Ohiosupras.org

Removing the mk3 fuel tank is relatively easy. Normal jack stands 5-6 notches up give plenty of room. The tank is not that tall but the filler neck obviously is. The hardest part will be getting the nuts for the straps loose. If they have rusted spray down with pb blaster or similar. Sometimes it's easier to unbolt the brackets from the body. The other end of the straps have pins with circlips. Take those lose after loosening the bolts to the last bit of thread. Oh, and remove the plastic trim piece from around the filler neck and the gas cap to prevent it from snagging on anything. Stuff the filler with a paper towel to keep dirt out.

For the mk3 I believe both pumps will need rewiring. The mk3 wiring is small anyways.

I removed the stock hardlines from the hanger top and used two -6 low profile right angle bulkhead fittings. I used two -6 to hose barb fittings on the inside.
 

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I ran the stock wiring on my TT Supra pump for ~18 months without issues. Since it dropped in 100% without modification I just rolled with it.

If you're planning on running a boost-a-pump or elevated base fuel pressures it'd probably be a better idea to re-wire though.
 

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I ran the stock wiring on my TT Supra pump for ~18 months without issues. Since it dropped in 100% without modification I just rolled with it.

If you're planning on running a boost-a-pump or elevated base fuel pressures it'd probably be a better idea to re-wire though.
Without issues that you know of. Did you monitor fuel pressure at full boost, voltage drop at the pump, or wiring temperature?
 

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Using the stock wiring and resistor with my walbro, my idle pressure was too low due to the pump seeing less than its desired voltage (increased current led to more voltage drop across the resistor).
 

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Without issues that you know of. Did you monitor fuel pressure at full boost, voltage drop at the pump, or wiring temperature?
Checked voltage @ the pump for other reasons and yes I had a FP gauge.
Never checked wiring temp but as my DD for 18+ months if something was gonna go bad, I figured it would have.

I'm not saying its a stupid idea to replace the wiring. I'm just saying that in my case, making ~400whp daily, a TT pump plugged into the stock wiring/lines worked out fine for me.


Using the stock wiring and resistor with my walbro, my idle pressure was too low due to the pump seeing less than its desired voltage (increased current led to more voltage drop across the resistor).
That's largely because Walbros hate getting anything less than about 13v, and on top of that they are flakey pieces of shit. Sure, they draw about half the amperage of a TT pump. But I'll take a reliable pump that needs beefier wiring for a twin pump setup that might also be a tougher fit into the tank, over any noisy twitchy walbro. They're just too hit and miss for me. Some work forever, some die in a week. Not my style.

That's very nice work on your FP hanger though!
 
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