Ford Mustang Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
7,217 Posts
Discussion Starter #1
So I've been wondering. At what point, real world, is it time to go past the Si-trim.

My current combination has my blower at 48,300rpm impeller speed. Thinking....If I were to switch to a Dart 363 shortblock and better heads. I would stay with the same Super Victor EFI and possibly jump to the B31HR version cam. (I LOVE the street manors with this B31)

Obviously boost pressure drops with the better flow and larger cubes. With doing this and keeping the same pulley setup in theory would my HP be be more based on less heat/pressure? If so...how far can I take an Si-trim. I know Vortech lists it at 55k RPM, 26psi, 775hp max but I would never go to 26psi. Can the Si-trim take me to 600 wheel and stay efficient enough? I would love to read compressor maps and figure it out on my own but I just don't "get it." as well as I'd like to.

What HP level should I consider going to the Ti? I just had this blower through a major rebuild (to a V1-HD) at Vortech and wondering if I should be kicking myself in the ass for not taking the awesome upgrade offer they made me to a Ti.

The plan for the car is not an emphasis on drag but open track and possibly some 1 mile events/road racing. It will stay non-IC'd. It runs fantastic right now and I have absolutely nothing to complain about. I'm just thinking about the future as I've got about 8 years of some seriously hard miles on this 347 and it's held together far better than I expected it to.

This isn't something I'm doing ASAP. Just want to open up some dialog with some folks that have taken things to their limits and soak in some wisdom.

Thank you.
 

·
Registered
Joined
·
951 Posts
I made 611rwhp with a 351w and a s-trim. It was with a 2.95 upper and 7" lower it made 12psi at 6K. It was a basic HCI setup.
 

·
Registered
Joined
·
7,217 Posts
Discussion Starter #3
I made 611rwhp with a 351w and a s-trim. It was with a 2.95 upper and 7" lower it made 12psi at 6K. It was a basic HCI setup.
Very nice! My setup now is 7 inch ASP lower pulley and 3 inch renegade upper. I had a 2.95 but decided on a grippier 3.0 when I did the rebuild. At my altitude I see 11psi at 6k.
 

·
Registered
Joined
·
60 Posts
Im currently on a somewhat similar path. I have a 331 with a s-trim and basic hci combo. I use a 3 inch upper and an 8 inch lower. Im pushing it to try and make 600 HP. I had it on the dyno last week. It made 500hp at 5000rpm then started slipping the belt. the operator tightened the belt up and it started blowing out the spark at around 5000. I took it home and put fresh plugs in it and it cleared it right up. Im putting a snow performance kit on it currently and heading back for more timing and RPM to try and make my goals. Please keep the forums updated with what you achieve from your SI. a new head unit may be in my future.
 

·
Registered
Joined
·
7,217 Posts
Discussion Starter #5
Im currently on a somewhat similar path. I have a 331 with a s-trim and basic hci combo. I use a 3 inch upper and an 8 inch lower. Im pushing it to try and make 600 HP. I had it on the dyno last week. It made 500hp at 5000rpm then started slipping the belt. the operator tightened the belt up and it started blowing out the spark at around 5000. I took it home and put fresh plugs in it and it cleared it right up. Im putting a snow performance kit on it currently and heading back for more timing and RPM to try and make my goals. Please keep the forums updated with what you achieve from your SI. a new head unit may be in my future.
I'd think with that pulley combo you'd kill my 347. What boost is it seeing?
 

·
Registered
Joined
·
60 Posts
It made around 14psi at 5000rpm before it started slipping before. I tightened it up and got it to hold but i ran out of dyno time. It appears to be making about 17 psi now. I just ordered up one of the new gates RPM blower belts to hopefully clean up more of the slip and get me to the 600 wheel mark next time i make it in to the dyno.
 

·
Premium Member
Joined
·
1,125 Posts
Im currently on a somewhat similar path. I have a 331 with a s-trim and basic hci combo. I use a 3 inch upper and an 8 inch lower. Im pushing it to try and make 600 HP. I had it on the dyno last week. It made 500hp at 5000rpm then started slipping the belt. the operator tightened the belt up and it started blowing out the spark at around 5000. I took it home and put fresh plugs in it and it cleared it right up. Im putting a snow performance kit on it currently and heading back for more timing and RPM to try and make my goals. Please keep the forums updated with what you achieve from your SI. a new head unit may be in my future.
Boy I hope you have a Dart block or R block or something!! My stock block split in half at 17lbs and 565rwhp. With meth and no timing. Haha Now I’m at 12lbs and 520rwhp, on another stock block. Tick...tick...tick
 

·
Registered
Joined
·
60 Posts
Boy I hope you have a Dart block or R block or something!! My stock block split in half at 17lbs and 565rwhp. With meth and no timing. Haha Now I’m at 12lbs and 520rwhp, on another stock block. Tick...tick...tick

Its built in a boss block with all the good stuff. Im gonna spin it hard and tune it aggressive then back it down just a hair and drive it.
 

·
Premium Member
Joined
·
1,125 Posts
Boy I hope you have a Dart block or R block or something!! My stock block split in half at 17lbs and 565rwhp. With meth and no timing. Haha Now I’m at 12lbs and 520rwhp, on another stock block. Tick...tick...tick

Its built in a boss block with all the good stuff. Im gonna spin it hard and tune it aggressive then back it down just a hair and drive it.
Outstanding!!! Can’t wait for a strong block so I can crank up my T-Trim.
 

·
Registered
Joined
·
7,217 Posts
Discussion Starter #11
I made [email protected] the wheel with the si trim. 8 inch lower with 2.8 upper.
Fantastic!

Boy I hope you have a Dart block or R block or something!! My stock block split in half at 17lbs and 565rwhp. With meth and no timing. Haha Now I’m at 12lbs and 520rwhp, on another stock block. Tick...tick...tick
I've tried to stay very mindful and prepared for this. The reason mine stays together is our correction factor. It makes 550rwhp on the dynojet but it's a 15-17% factor here in Utah's ####ty air. So I'm actually in the high 400's with actual power. I've made as high as 575 with meth but I removed it.
 

·
Registered
Joined
·
34 Posts
I am waiting on mine to get tuned now, stock 363 crate motor with an SI at 12psi and a pro-meth dual nozzle progressive meth system, hopefully it will make it on the dyno this week or next. I will update when I get the numbers.
 

·
Registered
Joined
·
7,217 Posts
Discussion Starter #14
I know I'm late here, but I wanted to piggy back off of this since mine is similar. 660+ with 8" lower and 2.9" upper. 15-16psi.
Wow, so if I want to break the 600-650 range the Si should do it just fine then. Woo hoo!
 

·
Registered
Joined
·
285 Posts
I am waiting on mine to get tuned now, stock 363 crate motor with an SI at 12psi and a pro-meth dual nozzle progressive meth system, hopefully it will make it on the dyno this week or next. I will update when I get the numbers.
What pulleys you using? Interested to see your dyno numbers
 

·
Registered
Joined
·
34 Posts
What pulleys you using? Interested to see your dyno numbers
I believe I have a 2.95 or a 3.12 upper, The guy that owned it before me sent out the pulley to have some coating put on it and it covered up the numbers. The lower is a 6.87 and it was making about 12lbs. I am still waiting on it to go on the dyno as we speak, it's at the tuners now, so hopefully soon. I will certainly update as soon as I know
 

·
Registered
Joined
·
7,217 Posts
Discussion Starter #19
We make 700 rwhp pump gas with meth injection, 7" crank 3" blower pulley. On 17" drag radials went 138 MPH in the 1/4 @3400#
With an Si? Solid!
 
1 - 19 of 19 Posts
Top