My car is a weekend cruiser with the occasional trip to work. Also take a couple long cruises where I may see 200 miles in a day. My question is, can I safely user meth injection instead of an intercooler on the street or is an intercooler the better way to go? I would have to do some butchery on my core support, chrome bumper, and grille brackets to get a decent sized intercooler in my car. Don't want to do it, but will if I have to.

 

Have you considered going air to water? For street work (the odd pull through the gears with plenty of recovery time) and even track work (again lots of time to cool off) air to water will work fine. Would be easier to package than a large air to air intercooler although will add complexity and weight.

At least with intercooling you don't need to worry about the meth levels on a long cruse. Plus you can always add meth in there as well to get super low intake temps.

 

I actually never considered water. There is so much going on under the hood that I wanted to keep it simple. I am not very familiar with the a2w systems.

 

have a friend in the exact same situation. after dealing with 200* IATs hes putting an A/W in.

 

I ran several Prochargers w/o IC'ers, but with a turbo I am not sure if they see more heat-I would think so, about to find out, lol
I am starting out with my build with no IC'er, but also starting out with a blowthru carb-on a long trip seeing little to no boost I wouldn't think the IAT's would be to bad, but would have to mont. them

 

I guess I should have noted that I'm also using a blow through carb. I just feel like no matter which way I go, I'll wish I went the other way.

 

E85 and be done with it.

 

i run a blow through on e85.. with a single nozzle meth.. everything stayed the same but i had to jet up to keep my afr the same after i put w/a intercooler, has gone 3 tenths quicker and 3-5mph faster at the same tracks.. and this is only on 14psi low boost setting..

 

How much boost do you want to run? Whats your compression? Cam? SCR? DCR? Type of fuel used? Engine size? Redline?

All make a huge difference in what you can "get away with". In general I'd say yes, of course you can run meth instead of an IC. In order to take full advantage of it with big boost you have to spray LARGE amounts. Much more than what is considered the "norm".

Honestly with all the shapes and sizes of intercooler you should be able to find a decent cheapish A2A IC that will fit. (look at treadstone intercooelrs) IMO if's pump gas I'd run both an A2A and a typical meth inj. kit. Both are relatively cheap and one will complement the other. Since you can't fit a nice huge IC, a small IC with meth inj will act as a much larger IC would. You also wouldn't have to spray the huge amounts required to run with no IC at all.

 

I currently have an A2A IC and will add meth on pump 91 just to be safe. Ive seen people run non IC and meth only, but low boost. The tune of course plays a factor in that as well.

 

Well it's a stock bottom end lq4 with ls9 gaskets and arp head bolts. CSU built blow through 750 carb. Victor intake with a Tick turbo cam. Manifold hot side with a gt45 turbo. Turbo 400 transmission and 3.36 gears. Plan to to max boost out at 12-15 lbs. The car weighs 4100 with me in it. Hoping to make it reliable and a reasonably fast sleeper. So the basic idea I'm getting is it would be better to run at least a small intercooler with meth as insurance as opposed to running only meth?

 

Procharges will add just as much heat as turbos at full boost. There is very little heat transfer form the CHRA to the compressor housing. The only way a turbo would heat the air more than a centri is because they hit full boost sooner.

If you have room for a intercooler why not stick one in there.

 

Lq4s are 9.5:1. (bit less with the LS9 gasket) "Tick turbo cam" doesn’t tell us much. Need to know the actual specs to estimate your DCR. Talking about the cheapo china gt45? Great turbo for the money and breaths well on the exh side. The compressor is relatively small and will heat up the air pretty good at 15lbs. I'd suggest both for a pump gas build.

Do you have a measurement on your available space without cutting the core up? What make/model chassis? Pictures?

 

your better off running no IC'er as opposed to a small one, you will only create a rest, more heat
I wouldn't be afraid to run w/o an IC'er on the street, if little heat transfer on a turbo-get meth and tune it to come in around 6 lbs of boost for safety
the thinking is a carb will lower IAT's due to the mixing of air/fuel before the head
I assume your running the MSD controller, set it up to retard timing boost related
I am starting out turbo no IC'er, carb, for the rest of the year, then install an IC'er this winter
I did some testing years ago, old D1B Procharger, @ 18 lbs of boost no IC'er I was seeing 330 degs air temps out of the Procharger, so I added an IC'er, was still around 190 degs to carb, never had a problem heat related
Gail Banks and some others offered twin turbo setups, no IC'ers
remember your street driving, giving it a hit now and then, so you wont see boost al the time, or little, and have the meth for safety
A/A would def be a plus, no argument there-I even made up an A/W on one setup, had the IC'er under the hood where the bat was, a small water tank, and a small rad. in front-worked decent, but for the street, A/A would have been better-it was more of a labor of love than function, lol

 

I don’t agree with this…

A small high flow IC will not add heat to the system. As long as you run the appropriate IC and don’t have a massive pressure drop across the core, an IC is always beneficial. Meth/water injection on top will help fight off heat soak of the smaller core as well as continue to drop CC temps. A2W units are a great example of this. They are tiny and provide very little pressure drop across the core.

2.5” coldside piping is more than enough and your hotside is on the large side as well. 2.25 or even 2” would perform better. Most go overboard on the piping sizes. You’re much better off reading a book or two and paying less attention to the “monkey-see monkey-do” mentality. There are very few builds on this site where the creator has done the math and built an appropriately sized turbo system for their application. (myself included)

The idea that carbs create better/cooler charge than FI by “mixing the fuel before the head” is a pointless statement IMO. The temps in the actual CC are the most important.

By injecting a better atomized fuel mixture as close to the CC as possible (ie Fuel injection) you will net cooler CC temps. This results in a more efficient burn and requires less IGN lead for the same amount of power. With a carb you have poorer atomization/distribution, slower burn rate (requires more lead), and waste some of the fuels cooling ability on the intake manifold/runners. A “Cool to the touch” intake manifold is a sign of this. It is also a sign of wasted energy that would have been better used in the CC. Engine manufacturers are switching over to direct injection fuel systems for this reason. As far as peak power production goes, a carb will not perform better than FI without an intercooler. It will require more spark lead. (From what I’ve read anyway)

You also can’t compare twins or huge single turbos to the OP’s setup. They move more air and generate less heat doing it.

A2W is also a great option. You’re already heavy, so the added weight isn’t a deal breaker. Tiny cores can be used and they can be placed about anywhere.

 

Sorry for the delay and lack of info.... working nights sucks. Anyway, the cam is an off the shelf cam. 235/231,
61x/59x, 114+6. Yes it's the cheapo turbo, which I realized was probably a mistake. This being my first venture into FI, I didn't want to get in too deep should I have to bail or something goes terribly wrong. But after the carb, tial bov&wg, cam & springs, etc... seems stupid to go cheap on the turbo. If all goes well I will upgrade it.

As for space I will take exact measurements and post pics of the space I have to work with.

Also, what are the characteristics of a "good" intercooler? Is there a way you can tell by looking at the design and build if it will have an excessive pressure loss?

 

For the intercooler just go for the biggest and best unit you can fit. Garrett and bell make great intercoolers. A lot of people are using treadstone units with some susses.

If you can post some pics of the space you have any people will be able to recommend units for you.

 

Great post!

There lots of reasons carbs aren't in top flight motorsport these days (where rules allow injection).

 

Nothing wrong with that turbo, they have proven themselves many times over. It will heat up the air a bit at higher boost levels though. Generally speaking if you want to run a “hot air” car you over turbo it so help keep the air charge cool.

That cam will bleed off quite a bit of compression, so that’s working to your advantage. Honestly with that cam I’d almost try meth inj by itself first. If you plan to run both anyway, might as well try just the meth first. I’d keep your timing at 8-9* at first and 8lbs or so. Watch the plugs close. For speckling. Dial in your boost first, then bump up timing slowly. Also if your running an AIT sensor I like to keep it upstream of the meth inj. Otherwise your sensor gets covered in meth and gives false cool readings that aren’t good to tune by IMO.

I’d look at the devils own kits. They have great pumps and are priced reasonably. I’ve installed about 6 of these kits (4 on my own cars) and never had an issue. If you plan on running a lot of meth a progressive kit is almost a must. I will say if you want to run 100% meth the push-connect fittings are one time use. The o-rings in the fittings swell with methanol and if you pull out and try to reinsert the hose, it will cut the o-ring every time. If left alone I’ve never seen one leak. Devilsown nozzle size calculator is pretty spot on if you run 50/50 as well. Just double the number if you run straight methanol.

As for intercoolers look for an advertised pressure drop at specific CFM ratings. (you won’t find these on cheap china cores usually). You want the lowest drop possible. 1-2psi at the rated power level is considered “good”. Be realistic when you pick an IC. If your making 600hp don’t buy a 1200hp core IC. Your just adding volume to the system. Treadstone performance’s site sells good “middle ground” intercoolers at decent prices. They will give you the pressure drop at “X” CFM. You can generally go off the 1cfm per hp rule for a good starting point. A horizontal flow end tank IC flows more efficiently as well. Try to run one of those if you can.

Like this…



Not like this.




I just went through all this myself so this is like a refresher for me. I’m just regurgitating everything I read, not trying to sounds like a know it all. I’m far from a “Pro”. Just limping along with this stuff myself and trying to learn, so if others see anything incorrect I posted please jump in and let me know.

Good luck!

 

Forcefed, why do you say not to put a over rated intercooler in there? The internal volume of the core is relatively small and if the OP is worried about pressure drop a higher rated core will reduce pressure drop over one rated at his power level! Not to mention it will cool the air better to.