What can a turbo converter foot brake to?
11-26-2013, 08:48 AM
#12
So is a 2200-2500 footbrake common? Can I expect it to raise greatly with hydroboost? Im sure 4wd guys can footbrake more.
Are their anyways to tell if this converter is "right" without the track? I do think our local tracks are done with test and tunes for the year. I will have to check. Will a log on converter slip by locking the trans in 3rd gear, and watching it through the rpm band be able to help with what this thing stalls to in boost?
Are their anyways to tell if this converter is "right" without the track? I do think our local tracks are done with test and tunes for the year. I will have to check. Will a log on converter slip by locking the trans in 3rd gear, and watching it through the rpm band be able to help with what this thing stalls to in boost?
11-26-2013, 09:16 AM
#16
Exactly. I think we had this conversation before about shift points vs boost. It basically comes down to you need more turbo. Try out that ebay 80mm everyone seems to like. That should be a much better match for you. Or you could go down to a 5.3, but I doubt you want that 
Also note worthy is you need to match your converter to your gears, for drag racing anyway. Most guys misunderstand this and proclaim "turbos want tall gears (3.42, 3.23, etc.)". Well not exactly. Plenty of turbo stuff runs really short gears (4.10, 4.56, etc.), but this requires you use a converter that can couple hard. With short gears and a lousy converter you will just blow through the powerband. Tall gears put more stress on the converter, but it seems most guys ignore this and leave a lot of power on the ground (actually just convert it to heat for the cooler to get rid of). To use steep gears you need to rev the engine up, which requires a turbo that can support higher rpms.
The whole idea in racing is who gets the most power to the ground. The person with the highest average power will win. I can show you this graphically if I need to. In your case, because you have too small of a turbo, you need a really tight converter. If you had a huge turbo, you would want it a little looser. This is where dyno time can be very valuable, you can see exactly where your setup is making/loosing power.
Your gears should depend on your converter, and tire size, and those depend on what kind of racing you do (1/8, 1/4, highway, etc.), and your converter depends on your cam, engine, size, and power adder, and all of this depends on vehicle weight. When you hear old guys say that a "well thought out combo is the key", they mean in it. That means taking into account EVERYTHING in a build and sticking to the plan.
In your case, your truck is heavy, and the turbo is too small. Your best bet would be to match the turbo to your other stuff you have now (converter, gears, engine).
Also note worthy is you need to match your converter to your gears, for drag racing anyway. Most guys misunderstand this and proclaim "turbos want tall gears (3.42, 3.23, etc.)". Well not exactly. Plenty of turbo stuff runs really short gears (4.10, 4.56, etc.), but this requires you use a converter that can couple hard. With short gears and a lousy converter you will just blow through the powerband. Tall gears put more stress on the converter, but it seems most guys ignore this and leave a lot of power on the ground (actually just convert it to heat for the cooler to get rid of). To use steep gears you need to rev the engine up, which requires a turbo that can support higher rpms.
The whole idea in racing is who gets the most power to the ground. The person with the highest average power will win. I can show you this graphically if I need to. In your case, because you have too small of a turbo, you need a really tight converter. If you had a huge turbo, you would want it a little looser. This is where dyno time can be very valuable, you can see exactly where your setup is making/loosing power.
Your gears should depend on your converter, and tire size, and those depend on what kind of racing you do (1/8, 1/4, highway, etc.), and your converter depends on your cam, engine, size, and power adder, and all of this depends on vehicle weight. When you hear old guys say that a "well thought out combo is the key", they mean in it. That means taking into account EVERYTHING in a build and sticking to the plan.
In your case, your truck is heavy, and the turbo is too small. Your best bet would be to match the turbo to your other stuff you have now (converter, gears, engine).
Last edited by Atomic; 11-26-2013 at 09:22 AM.
11-26-2013, 10:00 AM
#17
Thank you for your help atomic. I find it appropriate that you brought up gears. Since, I basically am tached out at 100mph. Which is not enough mph to run what most turbo guys do. Above that I am pushing my turbo out of its efficiency. This damn turbo tanks at 5400 rpms it seems like. A new turbo might save me from buying gears as well.
Ive struggled with this truck because I dont really know what to expect from each mod, and Ive had trouble prioritizing them. For example: I thought a converter was going to be a major change for my setup, because I have never had a converter change on a turbo truck. Judging from peoples opinions, I thought this might be what my truck needed to finally match it up. Same, with my tune up. I always think 2 psi, or a degree or 2 will make the difference. I really dont know what to expect with each mod, as Ive never done them before.
I always have money coming in slowly, so I try to spend it in the appropriate areas first. What would be your next order of mods? Turbo? Meth kit? 2 step? hydroboost? Tune up? Efans/Cutout? Leak down test(LOL)? Etc...
Ive struggled with this truck because I dont really know what to expect from each mod, and Ive had trouble prioritizing them. For example: I thought a converter was going to be a major change for my setup, because I have never had a converter change on a turbo truck. Judging from peoples opinions, I thought this might be what my truck needed to finally match it up. Same, with my tune up. I always think 2 psi, or a degree or 2 will make the difference. I really dont know what to expect with each mod, as Ive never done them before.
I always have money coming in slowly, so I try to spend it in the appropriate areas first. What would be your next order of mods? Turbo? Meth kit? 2 step? hydroboost? Tune up? Efans/Cutout? Leak down test(LOL)? Etc...
11-26-2013, 10:09 AM
#18
Each little thing you wont really notice, but when you do several at once is when you notice.
It comes down to being honest on what you want with the truck. Do you want a really good drag racer and sucks to drive around, or a good DD that is decently quick? And dont say a good DD thats really fast, because that requires gobs of money
I would do hydroboost first, just because its an easy mod and makes it safer to drive.
Efans are good and cheap, but not mandatory, and you can get a manual cutout for cheap and add the electric valve later.
Main thing is a bigger turbo, like that on3 or magnum 80mm on ebay, if you want to stick with that. s476s can be had pretty cheap as well, and would be a much better product.
It comes down to being honest on what you want with the truck. Do you want a really good drag racer and sucks to drive around, or a good DD that is decently quick? And dont say a good DD thats really fast, because that requires gobs of money
I would do hydroboost first, just because its an easy mod and makes it safer to drive.
Efans are good and cheap, but not mandatory, and you can get a manual cutout for cheap and add the electric valve later.
Main thing is a bigger turbo, like that on3 or magnum 80mm on ebay, if you want to stick with that. s476s can be had pretty cheap as well, and would be a much better product.