Hey everyone. Disclaimer, I'm fairly new to big fuel system stuff since I've never had a car making significant power, so I'd appreciate solid info and opinions as well.

I just recently got my car dyno'd. Made 377/363 with a sbe lq4 spec'd for boost. I currently am running a 255 pump and I plan to go to a p1sc or d1sc with a 6 rib setup (using poor man's belt wrap to hopefully eliminate pulley slip). I'm assuming I'll likely be somewhere in the 500-600whp range and obviously pushing the limits of my current fuel pump.

That being said, I'm weighing my options here. I really don't need much more fuel, if any at all, but like I said, it'll be close (but obviously I need something extra to be SURE). So I'm debating between going with meth injection system operated via a hobbs switch, a boost a pump, or running two pumps. Obviously two pumps would be waaaay safe lol. I've been leaning towards the meth setup because I have a friend selling a brand new snow performance kit for cheap if I want it.

Most of my friends say that running meth is a band-aid though and I understand the reasoning, but I see tons of people run hobbs switches on their double pump setups and I don't see the difference. The real risk for failure seems to be the hobbs, which if it fails in either scenario then things are going to break. Seems like all options are "band-aids" in a sense, unless you have a secondary pump with a manual switch that can run whenever you want it to or they're both constantly running.

Maybe I'm way off here, and tell me if I am. I don't mind. Just trying to learn some things and get some input from people with legitimate knowledge and experience on this.

Thanks!

 

If you plan to take 600hp, just put Walbro 450 in the tank. Thats easy enough pump to level what you plan. You need good wiring bcoz that pump take about 20A.
I would not use meth system to rich afr. There is too many things what can go wrong and hard to tune.

 

Yeah, I realize I could go with a bigger pump, but at that point I would have to remove the in-tank regulator and run one on the fuel rail. Which is fine, but at that point if I'm modifying the return line I'd probably just run a switched external pump and T it in at the rail.

As far as the meth option goes, I know it shouldn't be used as a substitute for fuel, but I'll be most of the way there if not there on my current pump. However, that depends on the numbers it makes, so I shouldn't make a decision based on assumptions/possibilities. I'm not concerned about the tuning aspect though. My tuner is probably one of the best in Ohio. I'd never go anywhere else.

 

If you already have a tuner, then they should be the one you reach out to for this type of advice. He is essentially tuning your car, therefore, would be the best person to give you the advise you need as far as your fuel system goes. That should be the person you find all your answers from. Just my personal opinion.

 

A good point. He's the one who will have to deal with my choices.

 

Meth is no substitute for fuel system. It barely even registers as an A/F ratio additional unless you are spraying way too much to be considered a reliable system for a street car.

elaborate
We are not going to fuel a high performance motor with water from a plastic tube, restricted at a single orifice intended for high pressure, from a pump which has a service interval (periodically replacement means eventually failure)
Because distribution problems at high flow rates of liquid content requires extensive plumbing. Furthermore optimum ratio of methanol is often found to be 70-80% mostly meth and because 51% methanol is flammable it isn't worth the risk to use this, the best possible liquid ratio for aux fueling on a street car.
Even if we could implement an elegant meth system with failsafes at high flow rates individual runner distribution etc... That would be awesome if you could actually use 75%+ meth, if the liquid wasn't flammable, too bad it is highly flammable so to be really safe driving around with such a system you're really spraying mostly water. It becomes a water distribution system. Which is great for pulling heat out of the engine, reducing the speed of combustion and reducing power output all simultaneously... Its a power remover button for turning down temperatures and its very easy to over-do. Very little water goes a long way so multi distribution isn't necessary.

 

Wow! Thanks for telling all of us what we ….. uh...… already know...

 

wrong!

 

Do you want to make more power or less? That's the real question.

 

how can it be wrong if it's my opinion?

Also it's rude to say something is wrong without saying why, but in this case there is nothing you can say so I get why you left it blank

 

Actually you are wrong, likely due to ignorance of not actually using it. Are you planning on sticking around this time, or going to get banned again for making long-winded highly inaccurate posts?

 

Still waiting to see how im wrong since the conditions under which I pretend to be correct are specifically fabricated to fall within my own personal preference range of safety margin for daily drivers

 

You're doing the exact same thing as last time....you pick out the 1% theoretical scenario that is loaded with YOUR bias to disprove what others do 99% of the time. There are entire platforms that use meth+water as a supplemental fuel for a factory fuel system that is limited and it does impact AFR. There ARE failsafe's (I have 1 of these systems that modify boost level based on meth flow, no meth no added boost). This is besides the fact that spraying methanol in a turbo setup effectively moves the compressor map to the right, supporting more power for a given size turbo. Stop talking in theory like usual or you'll end up banned AGAIN.

 

I quoted exactly what you said, which is an incorrect statement. Spraying meth, even a minor amount mixed 50/50 with water does change you A/F. Further, its recommended to use 15-20% of overall fueling in a street car by the manufacturer of the kits, why you wouldn't follow the manufacturers recommendation I have no idea but you seen to have your own ideas on how things work. Most of us in this forum speak from experience!

 

lol poor guy wastes so many words to say so little truth.

 

Bingo, not to mention for those with direct injection, it's a great way to decarbon those intake valves so you don't have to get them walnut blasted.

 

I'm still wondering how he got UN-banned....

 

This blew up a bit since I last looked lol. I'm still debating. I have yet to talk to my tuner. I'm thinking I may just run an external 255 with 6an lines and run it along with my internal 255 and call it good. I'd prefer not to if I don't have to, but I'm getting so much mixed info on this meth injection stuff.

 

The stock fuel line isnt a limitation until high HP (not the 600whp you're shooting for). Just stick a 340 or 450 in the tank and be done. If 1 of your 255's fail you'll run lean and risk damaging something.

 

I've NEVER seen a quality hobbs switch like the higher end Honeywells fail but ANYTHING can fail given enough time. I've seen pumps fail long before anything else so there is really no fool proof way, just mitigated risk but if you are always monitoring things that goes a long ways too. Ask your tuner if he likes to run meth or prefers not to because ultimately that should be your final answer since he's tuning it and you should go with what he is the most comfortable with for the best results.