Biggest Turbo for Automatic w/o NOS

Someone correct me if I am wrong, but isnt a T78 HUGE?... Huge + Auto doesnt really mix if its gonna be a daily driven car.. Id like to be corrected though, because Id like to have a faily large turbo on my auto and still have it enjoyable to drive.. Im pretty much set on the SP57 before Tranny/Fuel and then I wanna move to the 63 IF I still feel its necessary, but I always crave more than what I have... so im sure Ill want it eventually. ... but damn... I might wanna go with the SP66 even later down the road, so id like to know how big I can go on my Auto and still keep it 'fun and enjoyable' to drive.

I couldn't agree with you more, pooshda. That's exactly what I'm trying to find out.

Hopefully someone can provide us with an answer!

Bump

Well suuming you are running about a 4000rpm stall, I think it comes down to 2 factors.

1) What kind of driving/racing do you like to do?
2) How much lag is too much for you personally?

Both are very personal and probably can not be answered by anyone else. I know guys running small singles who do not want any more lag, and I know guys running T-78's who say they could probably go a little bigger.

Personally I go back and forth just about everyday between getting a SP-63 and a SP-66. I'm setting my car up to darg race for the most part. My gut tells me the SP-66 will eventually turn slightly quicker times even off the bottle. At this point though, I honestly have not decided.

pooshda said:

Someone correct me if I am wrong, but isnt a T78 HUGE?... Huge + Auto doesnt really mix if its gonna be a daily driven car.. Id like to be corrected though, because Id like to have a faily large turbo on my auto and still have it enjoyable to drive.. Im pretty much set on the SP57 before Tranny/Fuel and then I wanna move to the 63 IF I still feel its necessary, but I always crave more than what I have... so im sure Ill want it eventually. ... but damn... I might wanna go with the SP66 even later down the road, so id like to know how big I can go on my Auto and still keep it 'fun and enjoyable' to drive.

Click to expand...

The T78 isn't really as big as most people think. It is about the same size as a T66. There was a thread recently comparing the T78 to the T66, basically what Angel and Ryan Woon said was that they have the same characteristics. There are a couple of people that run T66's on auto's (Stage7) and they don't complain about it. Also, Humberto Aubi ran in the 9's with a T78. I think a SP70 would be real nice, it looks pretty promising so far.

-Amir

forcefeed said:

The T78 isn't really as big as most people think. It is about the same size as a T66. There was a thread recently comparing the T78 to the T66, basically what Angel and Ryan Woon said was that they have the same characteristics. There are a couple of people that run T66's on auto's (Stage7) and they don't complain about it. Also, Humberto Aubi ran in the 9's with a T78. I think a SP70 would be real nice, it looks pretty promising so far.

-Amir

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I've run an SP-66 on mine and I've driven Roberto's (stage7) as well. The lag is significant, but livable. Personally, I would go with a 63 as the best all round turbo for an auto, although you might be able to do slightly better at the track with a 66. I've pulled 10.2 on a 63. For a turbo that hits hard at 4200 rpm, it doesn't get much better than that.

If you do go 66, make sure you get a "Q Trim". I tried a P Trim and it was a dog. The Q Trim works much better on a 66.

Can you explain what "Q" and "P" trim is?

And, correct me if I'm wrong. But, anything over SP-60 will require fuel system upgade, right?

supratt96 said:

I've run an SP-66 on mine and I've driven Roberto's (stage7) as well. The lag is significant, but livable. Personally, I would go with a 63 as the best all round turbo for an auto, although you might be able to do slightly better at the track with a 66. I've pulled 10.2 on a 63. For a turbo that hits hard at 4200 rpm, it doesn't get much better than that.

If you do go 66, make sure you get a "Q Trim". I tried a P Trim and it was a dog. The Q Trim works much better on a 66.

Click to expand...

Have you taken the SP66 to the track or the dyno yet? How does it compare in power to the SP63. Thanks.

-Amir

Maybe this will help. I have a t66 and should have gone alot bigger because there is no lag. Put oit this way if you have a bpu car and both of you puch it from say 20mph my car out spools it by a bunch. So if you dont think stock lag is bad then I would go with a T-72. Just so you know this car acts and drive just like a brand new car, until you hit the throttle that is
Make sure you get the 4000 stall

hsk73 said:

Can you explain what "Q" and "P" trim is?

And, correct me if I'm wrong. But, anything over SP-60 will require fuel system upgade, right?

Click to expand...

The trim refers to the exhaust side turbine wheel. The Q trim is larger and has a slightly greater pitch to the impellers. This allows it to use more of the engines exhaust enenrgy to spin the compressor side turbine. In theory, it should be a little laggier than a P trim but make more HP. The reality, at least on a 66, is that it actually spools quicker than a P trim and makes quite a bit more power throughout it's rpm efficiency range. This turbo does not hit hard till about 5100 rpm. This is why I do not recommend it for a day to day street driven car. The lack of low end power can be pretty frustrating.

You can go with a larger turbo on stock fuel, but you will be limited to no more than 15 to 17 psi boost. Any more than that and you will be tempting fate.

forcefeed said:

Have you taken the SP66 to the track or the dyno yet? How does it compare in power to the SP63. Thanks.

-Amir

Click to expand...

I have not dynod it, but I did take it to the track. My best drag radial time 10.27 at 130 mph was on a 66.

All things being equal, you should get about 3 to 4 more mph out of the 66 at the track, but you may or may not run a better ET than a 63. The 63 has a broader torque curve which is favorable for drag racing.

By the time I ran the 66 at the track, I was haveing some other issues with the car that prevented me from getting reliable results. But, running the car on the 63 with the same issues (all things equal) the 66 Q trim did do about 4 mph and 3/10s better. So I suspect that the 66 may actually perform better at the track, but to date, my best run has still been on the 63.