centrifugal s/c people

[LANDY]

I have been thinking of going to a smaller pulley on the unit, and putting a waste gauge and setting it to 10psi. So my boost can come in sooner, have any of you done that?
Does the iat raises up with doing that?
Tell me about your experience and thoughts.
I have also heard is kinda difficult to tune.
Thanks.
Landy.

[sailsmen]

Up grade to a "T" trim. Do you really want "pop goes the ..............?"

[ImpalaSlayer]

so basically, you want to run a smaller pulley for more boost so it spools the engine up quicker, then dump off excess to avoid the sonic boom? interesting idea, never herd of that before but then again i dont read much on centris

[LANDY]

so basically, you want to run a smaller pulley for more boost so it spools the engine up quicker, then dump off excess to avoid the sonic boom? interesting idea, never herd of that before but then again i dont read much on centris
Just like that Dave, I read about it on mm&ff mag, they did it on car and put in the pulley for 18psi and adjusted the wastegate to 14psi. It got them 655rwhp and 655rwtq. The boost hitted 14psi at 5000rpm and stayed that way all the way to 6500rpm.
Then made a tune for 18psi and closed the wastegate. it ran 864rwhp and in the high 700 rwtq mark. And it was seen 14 psi at 5k rpm, then peaked 18 psi at 6500rpm.
I don't want to go that radical for obvious reasons (boom).
I would like to see 10psi from 5k to 6k rpms.

[blazen71]

You will still need a bov and it must be a blow thru MAF set-up. I've seen these setups on some of the Mustang forums.

[LANDY]

Yep.that's the way to do it. S/c to blow thru maf to wastegate to intake manifold.

[sailsmen]

I assumed you had a blow thru.

What a waste of time when members ask for technical help and do not post their mods.

[ImpalaSlayer]

I assumed you had a blow thru.

What a waste of time when members ask for technical help and do not post their mods.

he didnt mention it because it wasn't part of what he was asking

[LANDY]

I assumed you had a blow thru.

What a waste of time when members ask for technical help and do not post their mods.
Check my garage and you will see. It's a plain air to Air s- trim with a 3.6 pulley. If that saves you some time.
Btw upgrading to a t-trim won't accomplish what I want to do.

[sailsmen]

You can link your garage in your sig.

A "T" trim will accomplish exactly what you are asking for. The boost come on sooner with a "T" trim.

At 4K RPM S trim I had ~5 psi and w/ a T trim ~8 psi.

[sailsmen]

10-12-2005, 08:01 AM
Zack
Im a Professional it Seems


Join Date: Nov 2002
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Age: 31
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My Specifications, for all to know.

--------------------------------------------------------------------------------

Yes, I had my engine beefed up. And I might note I did not blow up my original engine. I pulled it out of the car running perfectly.
It is a forged 4.6, thats it.
It has CP pisting, Eagle rods and a 4340 Steel Crank.
Absolutely no head work, but I did have Crower Valve Springs installed to be safe. Stock cams, 10.1:1 compression. I also eliminated the EGR.
Ive upgraded to a T-Trim blower with a 2.90" pulley. This is supposed to make 16lbs of boost, but I am limited to 14lbs right now because I havent converted to the 8-rib setup. After 5800rpm's. the power levels off due to belt slippage.
My latest dyno while at Dennis's shop produced 492rwhp and 457 rwtq.
Flat 12.0 A/F
I finished this motor build up literally 4 hours before driving 1100 miles to Florida last month. When I ran the 11.69 at Gainesville, it had about 1200 miles on the fresh engine.
I dont have Nitrous or the Sneeky Pete System. Nor do I have the Methanol injection kit (But I will have it soon)
The car is a beast. I got 19mpg to and from Florida.
Im going to the Strip this Friday night in hopes of a new personal best.
I will let everyone know the outcome.
__________________
I own a BLUE MARAUDER....
....the only color
http://www.mercurymarauder.net/forums/showthread.php?t=21836&highlight=t+trim

[RR|Suki]

You can link your garage in your sig.

A "T" trim will accomplish exactly what you are asking for. The boost come on sooner with a "T" trim.

At 4K RPM S trim I had ~5 psi and w/ a T trim ~8 psi.

I don't think you understand what he wants to do, he wants the boost to come on harder yes, but he is also trying to max it out at a level that won't kill his stock motor. So where a bigger blower will make boost sooner, it's also going to make more boost, not to mention cost a lot more than what he is trying to do.



Anyway, yes I've seen the article you are talking about man, and it looks pretty doable. Just seems like a lot of time and little kinks might pop up. Either way, it's been done so it's not like you'd be out in the wilderness by yourself on the project.

[LANDY]

Rrsuki is.yours a blow thru.

[RR|Suki]

Rrsuki is.yours a blow thru.

no sir, I run a 100mm draw thru. Been thinking about switching to blow thru though. Then I wouldn't have to run my filter in the bumper :lol:

[FordNut]

It can be done but it's not as easy as it sounds. I tried it on my ProCharger setup years ago. Boost controllers are setup to operate a waste gate, not a blowoff valve. The waste gate bypasses exhaust gases prior to reaching the turbo. When you setup a system like this to operate the bypass valve it is hard to get smooth operation, it is more of an oscillation of boost/noboost than a smooth boost bleedoff.

[LANDY]

That sounds complicated Brian, I was also told that is very hard to tune because of what you just explained.

[ImpalaSlayer]

It can be done but it's not as easy as it sounds. I tried it on my ProCharger setup years ago. Boost controllers are setup to operate a waste gate, not a blowoff valve. The waste gate bypasses exhaust gases prior to reaching the turbo. When you setup a system like this to operate the bypass valve it is hard to get smooth operation, it is more of an oscillation of boost/noboost than a smooth boost bleedoff.
so if i understand that correctly, the bypass valve opens and closes repeatedly instead of a steady modulation?

[FordNut]

so if i understand that correctly, the bypass valve opens and closes repeatedly instead of a steady modulation?

That was my experience, and it equated to surging instead of a boost/power limiter. I gave up on it, even though in theory it should work. Maybe a smaller bypass valve dedicated to the boost limiting function would have been better. Especially if it was added onto the system in addition to the original bypass valve which could be setup to operate as a normal bypass valve.

[DOOM]

Pm mongoose.

[RR|Suki]

That was my experience, and it equated to surging instead of a boost/power limiter. I gave up on it, even though in theory it should work. Maybe a smaller bypass valve dedicated to the boost limiting function would have been better. Especially if it was added onto the system in addition to the original bypass valve which could be setup to operate as a normal bypass valve.

This right here is why you would want to use a waste gate, I think they have more resolution as far as opening etc. Which is why people who have done this successfully have used a waste gate, not a bypass/blow off. You'd still have to have a bypass/blow off as well for when you release the throttle.

[sailsmen]

I don't think you understand what he wants to do, he wants the boost to come on harder yes, but he is also trying to max it out at a level that won't kill his stock motor. So where a bigger blower will make boost sooner, it's also going to make more boost, not to mention cost a lot more than what he is trying to do.



Anyway, yes I've seen the article you are talking about man, and it looks pretty doable. Just seems like a lot of time and little kinks might pop up. Either way, it's been done so it's not like you'd be out in the wilderness by yourself on the project.

A T trim with a bigger pulley. You can send in your current SC and upgrade to a T trim. It will probably cost less then the alternatives that are beiung proposed, developing what is being proposed cost money and has a risk.

[RR|Suki]

A T trim with a bigger pulley. You can send in your current SC and upgrade to a T trim. It will probably cost less then the alternatives that are beiung proposed, developing what is being proposed cost money and has a risk.

he wants to make 10psi at lower rpm then stop at 10, upgrading to a T trim isn't going to do that, it will make more psi until redline. Whether it'll work for him or not is a different matter. It has been done though.

[sailsmen]

he wants to make 10psi at lower rpm then stop at 10, upgrading to a T trim isn't going to do that, it will make more psi until redline. Whether it'll work for him or not is a different matter. It has been done though.

http://www.mercurymarauder.net/gallery/data/500/s_vs_t-trim_map.gif (http://www.mercurymarauder.net/gallery/showphoto.php/photo/18308)

"In that graph, the orange lines are the boost vs. flow vs. compressor rpm curves. Notice how there are not 2 sets of curves. The same set applies to both compressors (unless I'm interpretting it wrong). With the same compressor curve, you get the same boost at the same airflow when you turn the compressor the same rpm. However, there are 2 sets of efficiency islands, which show where the T is superior.

This tells me that the impeller OD and volute shape is the same for the S and T trim. The T trim, however, has a bigger inducer, allowing more flow and more efficiency at high flow, without increasing boost.

I'm saying that you'll get more power at any given boost level due to the increased efficiency. The T-trim will be most efficient at high flow in the 15 psi range. The efficiency will get you cooler IAT's and less power to drive the blower. Mine made good power at 13 psi. I tried spinning it faster but just got belt slip even with the Reichard pulley."


ENGINEERMike

[RR|Suki]

http://www.mercurymarauder.net/gallery/data/500/s_vs_t-trim_map.gif (http://www.mercurymarauder.net/gallery/showphoto.php/photo/18308)

"In that graph, the orange lines are the boost vs. flow vs. compressor rpm curves. Notice how there are not 2 sets of curves. The same set applies to both compressors (unless I'm interpretting it wrong). With the same compressor curve, you get the same boost at the same airflow when you turn the compressor the same rpm. However, there are 2 sets of efficiency islands, which show where the T is superior.

This tells me that the impeller OD and volute shape is the same for the S and T trim. The T trim, however, has a bigger inducer, allowing more flow and more efficiency at high flow, without increasing boost.

I'm saying that you'll get more power at any given boost level due to the increased efficiency. The T-trim will be most efficient at high flow in the 15 psi range. The efficiency will get you cooler IAT's and less power to drive the blower. Mine made good power at 13 psi. I tried spinning it faster but just got belt slip even with the Reichard pulley."


ENGINEERMike

and... what does that have to do with the question asked? He wants to be able to make boost early whilestopping at the early boost lvl so he doesn't make so much peak HP that he hurts his stock motor. What you are talking about has nothing at all to do with what he's asking. He wants the boost to stop building at a certain point instead of continuing to build to redline.

[FordNut]

The T trim DOES make boost earlier. Just pully it for the max boost you want and go with it.

Same thing applies to a ProCharger D1 vs P1.

[Motorhead350]

If you already have a 3.6 pulley on a stock engine leave it alone. If you wanna go faster be ready to spend more than a tune and a few small parts if you want it done right.

Just my opinion.

[sailsmen]

the t trim does make boost earlier. Just pully it for the max boost you want and go with it.

Same thing applies to a procharger d1 vs p1.

thank you!

[RR|Suki]

What does that have to do with his question? It's pretty irrelevant that it makes boost sooner, because no matter what, it will continue to make boost till you shift. If he puts on a pulley for 10psi at 6500, that's where he'll see the 10 psi. He wants to see 10psi at 5000 rpm -6500 rpm. That's what he asked about. No matter what trim he has he cannot see 10psi at 5000rpm if he put on a pulley for 10psi @ 6500. So if he puts on a pulley to see 10psi at 5000, unless he has mega belt slip he's going to see a lot more than 10psi at 6500 unless he can bleed the boost off. That's all he's asking about. . .

The quote in black is all he's asking about, I'm pretty shocked that it's been missed over and over


Just like that Dave, I read about it on mm&ff mag, they did it on car and put in the pulley for 18psi and adjusted the wastegate to 14psi. It got them 655rwhp and 655rwtq. The boost hitted 14psi at 5000rpm and stayed that way all the way to 6500rpm.
Then made a tune for 18psi and closed the wastegate. it ran 864rwhp and in the high 700 rwtq mark. And it was seen 14 psi at 5k rpm, then peaked 18 psi at 6500rpm.
I don't want to go that radical for obvious reasons (boom).
I would like to see 10psi from 5k to 6k rpms.

[Marauderman]

The T trim DOES make boost earlier. Just pully it for the max boost you want and go with it.

Same thing applies to a ProCharger D1 vs P1.

Sure glad I upgrade mine to a T-Trim a few years back---cause that's all I need to do whenever I decide......

[sailsmen]

Lets make it simple. We assume your goal is to go faster and quicker while maintaining the same max 10 psi.

Two exact cars. One has a T trim and one has an S trim. Both have same max boost of 10psi. The T trim is faster and quicker.

Why? Keep it simple. Noise level was a design criteria for the S trim. Noise was not a design criteria for the T trim. Result the T trim is more efficient producing same "boost" with less heat and requiring less parasitic drag.

The chart I posted reflects this.

Several members in the past have reported same upon switching to a T trim.

[LANDY]

I would be nice to get a t- trim, and a s- trim dynograph on our cars to compare.

[sailsmen]

Just look at the Vortech graph I posted and the quote from ENGINEERMIKE.

[RR|Suki]

Lets make it simple. We assume your goal is to go faster and quicker while maintaining the same max 10 psi.

Two exact cars. One has a T trim and one has an S trim. Both have same max boost of 10psi. The T trim is faster and quicker.

Why? Keep it simple. Noise level was a design criteria for the S trim. Noise was not a design criteria for the T trim. Result the T trim is more efficient producing same "boost" with less heat and requiring less parasitic drag.

The chart I posted reflects this.

Several members in the past have reported same upon switching to a T trim.

No kidding, that's why the T trim is an upgrade. All that still has nothing at all to do with the question asked, Which was making the same amount of boost from low RPM till you shift :o



I would be nice to get a t- trim, and a s- trim dynograph on our cars to compare.

If you search there are a number of posts by people who have moved from one to the other. The higher CFM superchargers make a good deal more power with the same pulley.

[Joe Walsh]

I understand what you are trying to do,
But if you pulley the S/C to get 14 psi boost at a lower rpm, then bleed off excess boost to maintain 14 psi all the way up to 6500 rpm,
don't you have to take impeller speed into consideration?

From previous posts, it sounds like it has been tried with less than great results...I would get a PD/TS blower before going through all that trouble.

[LANDY]

I understand what you are saying Joe, I just wanna try something different and my car is already setup for a centrifugal all around

[sailsmen]

The answer to go faster with the same psi is to upgrade to a T trim. Send in your unit to Vortech.

[FordNut]

So what is the objective here anyway? If it is to make boost come on sooner then basically flatline, it's going to be a big hassle to make it work. If it is to make POWER sooner while sticking with a centrifugal setup, a blower upgrade will do it. You will need a bigger blower pulley to slow down the bigger blower a little bit because with the same pulley it will make more boost. The smaller blower's pressure curve looks kind of like a ramp that starts at 2k-3k and continues to climb until redline. The bigger blower's pressure curve is more of a step at 2k or so then a ramp that continues to climb until redline.

[RR|Suki]

So what is the objective here anyway? If it is to make boost come on sooner then basically flatline

That's what he wants to try, and what he asked about. It's been done before, has to be done with a waste gate (not a bypass) bleeding off the boost. If he wants to try it too why not? it'll cost him a tial waste gate and some time with a welder, and a large pain in the rear. The waste gate may very well open up with that tiny blower bleed off the air and stall the car. Then you flip the waste gate on Ebay and build a motor that can handle a real blower, and upgrade to a T trim. Lessons learned, fun had ;)

[Loco1234]

If the motor is forged & can handle the 14 psi just don't limit it to the 10psi... You'll thank yourself later...

I using a JT-trim and over 20psi... It comes on early & just keeps pullling & pulling... I understand you want it to flatline but if you have the motor built right let yourself enjoy it... & modulate the boost via your right foot...

[LANDY]

Ok It seems like I might be up to lots headaches with that route, since my s/c needs a rebuild I might as well upgrade to a t-trim when I send it to them next month. Hope it doesn't break my budget.
Thanks for the input guys.

[LANDY]

Any one running a t-trim on 10psi?
What pulley are you using?

[ntd]

I'm running the Paxton Novi 1500(aka T-trim) I'm using the pulley Paxton ships with it IIRC it was a 3.8" I hit 10.5 psi.

[Blackmobile]

Well just for comparison the stock pulley from Vortech on a T Trim is a 3.6 and that puts out ~9.0 lbs and with an upgrade to a 3.3 pulley you'll get ~12.0 lbs.

Ed

[LANDY]

Ed, did you have both pulleys on your setup before you had your the engine built?

[Blackmobile]

Ed, did you have both pulleys on your setup before you had your the engine built?

Not really, When I got mine I immediately put the 3.3 pulley on and ran at ~12 lbs. When I sold the kit, the stock pulley was put back on and it ran at ~ 9.0 lbs with the new owner.

[Blackmobile]

Ok It seems like I might be up to lots headaches with that route, since my s/c needs a rebuild I might as well upgrade to a t-trim when I send it to them next month. Hope it doesn't break my budget.
Thanks for the input guys.

I would suggest going with a 3.3 pulley and have the headunit rebuilt to a V2 SQ Trim. IMHO, your MM will be a fast sleeper for enjoyment, but going to a T Trim is a prelim to becoming a race car.

[LANDY]

Ed im pretty sure they re not available no more,an they flow less than a s-trim acording to my search on the vortech website. plus im planning on purchasing an aluminator next year 8;5.1 comp ratio. that should get me to consistant mid 11's.(hopefully)

[Blackmobile]

Ed im pretty sure they re not available no more,an they flow less than a s-trim acording to my search on the vortech website. plus im planning on purchasing an aluminator next year 8;5.1 comp ratio. that should get me to consistant mid 11's.(hopefully)

I'm not sure if they're still available but they still advertise versions of them on their site.

http://www.vortechsuperchargers.com/view.php?pcat=17

As for the Aluminator with an 8.5:1 comp ratio, I'd try to stay close to 10:1 as possible for more hp on a built engine. I believe mine was 9.3:1 in an Al Papitto motor.

I also wouldn't short change the power of an S Trim. When I had mine Dyno'ed I was in the company of Magindat and Greggash. Rich was first with his first known blow thru procharged Marauder (flow of 1200 CFM) and he wanted his safe so it was ~435 RWHP. I was second with my Blow thru T Trim (Flow of 1200 CFM) And it made about ~445 RWHP, and it impressed me but I wasn't pleased since I had put the 3.3 pulley on. Gregg's Draw thru S Trim also with a 3.3 pulley (Flow of 1000 CFM) was next on the Dyno, and to our amazement his first pull netted him ~492 RWHP. All our jaws dropped, and when all was said and done mine went back on the Dyno for some more magic from Dennis. When mine was done it netted ~460 RWHP. So an S Trim can also be extremely powerful.

[sailsmen]

Ed im pretty sure they re not available no more,an they flow less than a s-trim acording to my search on the vortech website. plus im planning on purchasing an aluminator next year 8;5.1 comp ratio. that should get me to consistant mid 11's.(hopefully)

You will need 600RWHP Dyno Jet Inertia for consistant mid 11's. An 8 rib belt, etc., etc., etc. Going from 12's to 11's is like going from the Moon to Mars. It's a whole different "ball game".

[hotford]

Just spin the S trim faster and the car wil lay down some great numbers,save your money on the upgarde for now, if your worried about belt slipage then purchase a ATI Damper with a 7.5 diameter and the strim will really come alive.

[RR|Suki]

going to a T Trim is a prelim to becoming a race car.

T trim is still a baby size blower. When you get over 1500cfm then maybe it's a prelim to becoming a race car