V6 Bird

iTrader: (15)

There is no specific goal but you responded on how your enginneering taught you. Put your foot in your mouth now if you have no experience regarding what he wants to do. Just in thoery....

To the GTO...If the car builds hard boost (so it feels like to you) in 1st and 2nd, going to a numerically higher gear would just put you 1. up in smoke on the tires, and 2. way faster through the powerband.

A good rule of thumb is to not gear the car higher if it makes power. You want to keep the car in the power curve longer and most people do this with the right gear selection (usually lower) and the right converter to suit the power needs.

Gearing a car to higher numbers only makes up for lack of power..Hence why the Trex guys are using 4:30 and higher gears. The power band is very narrow with that size cam.

Ping King

iTrader: (20)

at one time someone thought putting a turbo on the back of a car is stupid and wont work.


i will agree its kinda stupid when you sit down and think about it....but it does work, and work well.

dont knock it till you rock it.

LSs1Power

iTrader: (5)

I was thinking about doing it and spoke with ECS. If you search under my name you will find a full thread about it. The final conclusion is to use a restrictor was alot better and easier than using a wategate. Another thing is that if the difference between peak psi with a restrictor and without is less than 4psi then it might work. More than that on a D-1SC will cause aloot of heat and will need around 90HP at max impeller speed to turn. So if you want to keep the 12psi then pulley to 15psi and put a restrictor on it.... that should work with no problem. It will bascially give you 3psi accross the board(50-70rwtq more) and will just stop going over 12psi at 6k RPM (your loss here will be slightly larger than running 12psi pulley though).

So at the end its a compromise... If you really want the extra TQ down low and in the midrange do it. Also a cam will do what u want... You will pick up 40-60rwhp with it accross the board.

Good luck.

kwiksilverz

Thanks, yeah- I really didn't want to change the gearing- I like making the car pull- that's why I have always liked nitrous and turbos. My only gripe is in the upper gears, it loses too much boost for my liking on the shifts.

My torque peak of 540 is right around 4800 (it is 400+ from 2300 on) and it holds flat from 4800 to redline with no drop off. My hp is a perfectly straight ramp from ~175 @2300 to 650 at 6800. Overall, not a bad curve- but I know it can be improved upon.

The cam idea is tempting too, I just like that fact this I am doing this on a bone stock motor and it is a challenge to me to optimize it before changing parts out.

Mike- I see both sides here and honestly respect yours also, but one thing I have noticed- and I commented on it one- is that things often vary in theory and practice. I have a few engineer friends who have the most well thought out cars I have ever seen, but they make the least power and run the slowest- with the most $$$ invested. Not saying you are that type at all, hell- I don't know you from Adam .

I did not come here to make waves, so I keep my opinions to myself- I just wanted various opinions and possibly hear from people who have done it to see which setup works the best and I appreciate the feedback I have gotten from everyone so far. Thanks again guys!
Joe

LSs1Power

iTrader: (5)

My looking at these 2 graphs will make it more tempting lol

The dynojet graph is at 7.5-8psi and the Mustang Dyno is at 11-13psi. The dip you see in the Mustang dyno is due to belt slippage (too large of a belt to use). We also ran out of fuel which is why we stopped at 6000 RPM Only.

V6 Bird

iTrader: (15)

Im sorry they told me the position was filled by Beaker that had an enigineering degree. They told me they were impressed by his calculations so they hired him on the spot.

Im not saying the engineer type isnt needed in motorsports but you have to give serious thought outside the box on what works and what doesnt instead of being critical on strictly mathematics like what your title ensues.

Yes his idea and combo will work for what hes trying to accomplish. Do I think there are better ways of getting down the track in his situation, sure. This is where we agree to disagree and capitalize on why ive been faster with less "education." LMAO

engineermike

Thinking outside the box with no regards to mathematics is what spawned the electric supercharger. What a great idea that was. . .

I'm absolutely certain that you have not been faster than me within the same constraints that I've set for myself. Also, there are many ways to go fast and knowledge of physics and engineering is only one of them. There are some local guys that are much faster than me, but they are also willing to spray alot of nitrous and spend alot more money than me.

kp

iTrader: (34)

Lets play nice guys or I will start deleting posts. Unless you have some results/numbers to prove your point its no different then using the math. Sometimes the math works and sometimes it doesnt, just like 'thinking outside the box' works and sometime it doesnt. If I remember right the engineers in the 60's said that no way would a car be able to run over 200mph in the 1/4 mile and they were wrong. But on the other hand without the engineers they sure wouldnt be running 300mph today.

You can make a point without the 3rd grade name calling, remember sometimes there is usually more then one 'correct' way to get a car down the track.

frcefed98

iTrader: (16)

Kev you are too nice, lets put it this way, next one who calls someone a name is headed for a nice long ban....

V6 Bird

iTrader: (15)

More then one way is correct..Delete some posts. Btw, if history serves me correct, he was the first to start with stupid or ignorance or what have you. Im done.

V6 Bird

iTrader: (15)

First of all, you wont see me putting "crutches" or "stipulations" on going fast.

As far as going fast...Try me. Fast is fast.

kwiksilverz

Thanks- maybe I'll go that route then. I was initially going to do a cam swap over the winter, but then wanted to see how far I can go on the stock stuff. On your chart- it shows you had 5.6 psi @ 3600?? I am making 12 at 6800, but only around 3 psi at 4500 or so. That is part of why I wanted to do something to bring it in sooner. I am also using a P1 too though, so maybe that's why. When I bought the car, I told myself I'd be happy with just the stock blower kit on the car and leave it alone so the P1 was perfect. I should have known myself better and gone D1, but I can't see it "spooling" faster. I do see some people making impressive numbers on P1's too though, mine impressed the hell out of me HP wise for the little I have done!
Joe

V6 Bird

iTrader: (15)

Stock cam has alot of cylinder pressure characteristics in the cam profile...Might want to reconsider your choice there as a precautionary measure.

Unfortunately with a blower it takes HP to make HP..Hence why down low it doesnt make much power. Even if you were to pulley up on this unit, im not sure the costs would outweigh the benefits in this application.

andereck

Well its costs next to nothing to experiment. The restrictors are nothing trick. Its just a disc with a hole in the center. You don't want radius entrys or anything like that as you're not trying to cheat the size. The P1SC has almost 10 sq inches of inlet area. I would try 70% of that for starters or a 3" hole in your blower inlet just after the filter and pulley up. Don't attach it to the supercharger itself or you won't be using the whole inducer. Keep in mind any inlet ducting after the restriction will be under vacuum at higher airflows and will collapse if its not rigid material.

kwiksilverz

OK, now- is the FM 9 too aggressive? I was wondering how it would do with the slightly larger displacement LS2. I have heard various schools of thought on cam selection also- 1) run a mild custom blower cam or 2) cam the hell out of it (like Trex), let it bleed off the cylinder pressure and boost the snot out of it.

I have a couple BBC friends 12-71's that make good power just using large cams with aggressive overlap and such, "high" (10:1 or so) compression and 20+ psi on pump gas and they say they have had better results with running "large" NA cams with higher boost vs. custom blower grinds and lower boost in terms of detonation and power. What do you think?

kwiksilverz

Cool, thanks! I may experiment then. I have never seen the restrictors to know if they were just a disc with a hole, or a custom beveled piece that mounted similar to our MAF. The piping to my blower is 3.5" colid pipe with only 2 short reinforced rubber hoses for couplers, so no worry of anything collapsing. Thanks again.
Joe

XLR8NSS

iTrader: (4)

How much vacuum in the inlet ducting is acceptable before causing problems with blower seals?

andereck

In a blow through arrangement (throttle at intake manifold) the impeller seal will always be under pressure. The restrictor stretches the air on its way into the impeller. No worries.

Pro Stock John

iTrader: (34)

I'm afraid I still don't get it, what is the original poster trying to accomplish, trying to cap the amount of boost?

LSs1Power

iTrader: (5)

Example,

3.6 pulley gives 12psi max and maybe 3psi at 3500 RPM.

3.4 pulley gives 14psi max and around 5psi at 3500 RPM. In this case the area under the curve is fatter... but since he doesnt want to go over 12psi at 6K RPM+ he will limit the boost by either bleeding the boost off or restrict it.