Competition Twin Turbo Setups

[OT-OF-HERE!!]

Ok, here's the parameters for support of drag racing with 650hp to 860hp:



1)Small Turbo - What size exh and compressor housing for support and quick spoolup?



2)Large Turbo - What size sxh and compressor housing that will make huge power but that will spoolup quickly enough to maximize their benefit for 1/4 mile. When making recommendations, pls include things like rake and pitch angles of the turbine and clipped tips or not, bearings (ceramic or ball) or whatever, cold pipes (3", 31/2, 4") looking for what works best in this setup. Downpipe size,... what do you recommend?



Ok guys, hook me up with your input and knowledge.

 

[OT-OF-HERE!!]

Twins

Bump! Ok, no opinions or knowledge to share??

 

[Forrest Nearing]

plenty, but you've got some wide parameters, and the only people who are going to be talking pitch angles and clipping turbine wheels are probably the turbo builders, and... well... good luck getting them to talk much

 

[wildmanben]

a lot of info can be found by using the search function.

 

[OT-OF-HERE!!]

Hmmmm!

plenty, but you've got some wide parameters, and the only people who are going to be talking pitch angles and clipping turbine wheels are probably the turbo builders, and... well... good luck getting them to talk much

When I've talked with different dealers then some talk about those things and I figure if you don't ask the question then you'll probably never get the answer from UNbiased sources.



Sounds to me like not too many understand these things and the net affect on a turbo and performance so we'll leave it as one of those mystery things people pay for and don't know what they're getting. Also I figure not everyone knows everything so it's perfectly ok for those that have some sold knowledge on some part of this to jump in,... . I wouldn't expect many to know deep detail on every aspect.



For example,... I was really looking for input somethiong like: For the small turbo let's try a 12/62 or 64 for best spoolup of the big turbo and then for a big turbo lets think 22/77 to 80 and use clipped tips to maximize spooling response and then for a large set like this then maybe a big external gate with a pop off may work best and it all comes together with a 5" downpipe and say 3 1/2" cold pipe. Set the gates for at least 80psi and firering the head. ... ... ... ... ... ... ... Now I just made all this c. . p up in this paragraph so it may make zero sense to someone who knows, but generally that's what I'm looking for so then to serve 650hp to 850hp or more then I would best know how to shop for a setup that will do the job. Make sense? Maybe I didn't ask the question properly. Thanks anyway.

 

[Forrest Nearing]

I'm not a big fan of clipped turbines... I prefer a turbine wheel designed to flow and operate under certain conditions vs. just blindly clipping a wheel. yes, I realize some of the very popular big offerings have clipped turbines, and they obviously work, but... you're going to have better response w/ an unclipped wheel. yes it's lighter, but the mass usually doesn't outweigh the leverage on the wheel.



also, 650-850 is a pretty wide range... a twin set that works great at 850hp might be a little sluggish at 650hp

 

[JRamirez]

I have sold three sets of ATS twins and the customers loved them. I have pictures of them on a customers 06 if you are intrested. -- email address removed --

 

[JR2]

Looks like he has a set of ATS twins and is still shopping.....

 

[OT-OF-HERE!!]

TWins

Looks like he has a set of ATS twins and is still shopping.....

Yep, I have a set of ATS original compound twins and it's like having a pair of tennis shoes that once fit and now they don't fit so you shop for the next bigger size. Clint and Mike have seen my truck at ATS and know my set is no longer big enough to cool as I need so they're doing some,... . let's say new and not yet advertised turbos in a set and I will probably end up going that way but I want to know what guys that have twins in the range I talked about recommend so I can see if that info matches up with what I'm looking at. It may seem like a large power range that I used above, but it is narrowing very quickly and by the time the rest of the planned mods are on then the high end should be right.

 

[paulb]

Okay, here's my $. 02 worth... I am at the low end of your hp range. I like the way that the setup I have works. For the upper end of your range I would go with a 66 over a big brother.



For drag racing I do not want to have to waste gate the big turbo. Picking a good combination of top and bottom turbos, and picking sizes that will supply the amount of air (boost), that you will need to reach your hp goals is the key. You should be able to adjust the wastegate on the top turbo, to adjust the balance between the two turbos, and then not limit the boost other then that. Actually a couple of blow-off valves is a good thing to have for safety...



If you go by the rule of thumb (I not sure that I do), of 11 hp per pound of boost, you would need to make 59 pounds of boost for 650hp, and 77 pounds of boost at 850hp. Build your engine accordingly.



I don't like clipped wheels. When drag racing, making boost to stage (initial boost), is not as critical as how fast the turbos will accelerate after launch. The quicker the turbos will make full boost the better. It does matter how efficient the twins are, if it take 6 seconds of a 12 second pass to make full power.



Paul

 

[OT-OF-HERE!!]

Okay, here's my $. 02 worth... I am at the low end of your hp range. I like the way that the setup I have works. For the upper end of your range I would go with a 66 over a big brother.



For drag racing I do not want to have to waste gate the big turbo. Picking a good combination of top and bottom turbos, and picking sizes that will supply the amount of air (boost), that you will need to reach your hp goals is the key. You should be able to adjust the wastegate on the top turbo, to adjust the balance between the two turbos, and then not limit the boost other then that. Actually a couple of blow-off valves is a good thing to have for safety...



If you go by the rule of thumb (I not sure that I do), of 11 hp per pound of boost, you would need to make 59 pounds of boost for 650hp, and 77 pounds of boost at 850hp. Build your engine accordingly.



I don't like clipped wheels. When drag racing, making boost to stage (initial boost), is not as critical as how fast the turbos will accelerate after launch. The quicker the turbos will make full boost the better. It does matter how efficient the twins are, if it take 6 seconds of a 12 second pass to make full power.



Paul

Sounds right. I was doing 63psi and then got concerned about not being fireringed so I turned it down to mid 50s. I have plans to let FloorIt firering it and then with the bigger set I plan to run I've been told 80psi is about where I will need to be so your calculations above are right on. Tks.



Good question or statement about how long it takes to make full boost. Really that's what it's all about when you're talking 12sec. So is there a rule of thumb on how long to reach full boost that marks an efficient set of twins? I would think maybe 2 or 3 seconds at the most. Sound right??

 

[paulb]

Sounds right. I was doing 63psi and then got concerned about not being fireringed so I turned it down to mid 50s. I have plans to let FloorIt firering it and then with the bigger set I plan to run I've been told 80psi is about where I will need to be so your calculations above are right on. Tks.



Good question or statement about how long it takes to make full boost. Really that's what it's all about when you're talking 12sec. So is there a rule of thumb on how long to reach full boost that marks an efficient set of twins? I would think maybe 2 or 3 seconds at the most. Sound right??

Mine will hit the blow-offs when it shifts to second gear... So yeah, around 3 seconds. I've never really timed it... too busy at that time... but I can hear the blow-offs...