Right now I have the BD Towing Twins. I want more air flow but really don't want to lose all bottom power or spool up.

However, I was told a bigger bottom turbo may allow quicker spool up. It will allow more air flow. Does this make sense?

So what turbo should I go with? BD has an upgrade to a s400 turbo -- but is there something better? And will it bolt in place like the BD s400 upgrade?

I want more power, but still need to tow. I want to push beyond 650HP, maybe 700hp. Soon I will be adding dual cp3's.

 

What you are asking for is why BD designed their race twins. Having a bigger lower turbo will not allow quicker spool up... if they did, BD would just sell the bigger set as tow twins!! Think about it...

BD spent a lot of time in designing what they have... you can make an argument about who's twin are better and what not, but i don't think you are going to improve with one turbo swap anything BD has spent a lot of time developing. With what you have, just upgrade to the BD s400 and you can still tow and be happy.

 

Moobesor, I have the towing twins too and want to upgrade. The tow twins are holding me to 580. I am going to 90 or 105 sticks and upgrading to the R700 set. What HP are you seeing? My buddy hits 650 with his BD tow ewins. So I need to see what my new goodies do for me, then I will decide. All trucks are different,

 

Dukcaln--

I think I have more fuel than what my tow twins can work with. Perhaps I am wrong. Seems like they flatten out at top end. I understand these are towing turbos and not race turbos. Can't get much more out of them.

I saw a thread someplace where MPI incorporated a different turbo for the bottom turbo (not the BD upgrade). My first question was: which is better -- the BD upgrade or an alternative? And I am asking someone who has made the change.

Not sure what HP I am making just right now. I'm sure it's the high 500's.

 

One thing we found with the R700 kit is that they tow very well. We were surprised at how well they responded. Our turbo engineer knew they would work well, but they work really well. I have driven our 06 at 500hp towing 8000lb and there was very little turbo lag. Only slightly different than the towing twins. With the power you are making I wouldnt hesitate to make the switch to the R700. Give me a call if you have any more questions.

 

What I forgot to mention is the performance on "towing" twins is going to be more predicated on the response of the top turbo more than the bottom one. This is because the most important part is the off-idle response getting you that first 5-15psi of air in the lower rpm range. If you like the way your top turbo spools and performs now... you'll be happy with the s400 under it.

 

Using the towing twins I made 725 Hp and I believe with a larger lift pump and some tuning time I could have got close to 750hp.
If your truck is low on power......have a look at your fuel system.

Power is not the issue with the towing twins...Heat as in extreme egt's is the problem.

The R-700 is a great setup. In terms of general drivability and towing I think it is a better choice than the towing twins....As long as you have over 500hp worth of fuel (not hard in the common rail). The R-700 is also somewhat quieter than the towing primary.....Something to be considered on long runs!

 

Can use BD tow twins get a good trade in for our s300 from you Pat. My set is fairly new and installed by Imler Diesel.

 

Sorry but we arent setup to do trade ins here. You could sell it and then give me a call and we can see what I can work out for you.

 

I got a "like new" s300 bottom turbo from a BD twin set. PM me if you're interested. You can buy the twin upgrade to make a great towing twin set.

 

I'm running the super B, and have plans to upgrade to the towing twins, what have you guys noticed are the advantages of twins and disadvantages if there any? Thanks