YenkoST

iTrader: (5)

I decided to start a new thread after the two page long debate in my other tread about timing. Ok, got new problems as well as old.

Quick rundown:
383, 195 AFR heads, GM847 cam, Victor Jr. intake, Accel 1550 cfm TB, Hooker SuperComps (1 3/4" equal length), Procharger D1SC 4" pulley, 60 lb/hr injectors at 54 psi on a boost reference FPR 1:1 so 60-62 psi at WOT.

Changes I've made:
-Gone to a 8 degree plug at .026. Heat Range looks perfect. Half of the plug is clean and the other half is rich on the fuel ring.
-Adjusted a fuel settings in the tune. Fueling is now 11.3-12.0. Need to smooth it out some and lean a few areas out still.
-Thanks for Bob at EBL, he has been working with me to get the speedometer for the TCI EZ-TCU to work and it finally works! Great guy and he worked with me to figure this out over 40+ emails!!

New issues:
Truck feels like it pulls better and is faster at 57% throttle than at 100% throttle. At 57% throttle, I'm making 3psi with it notching 4psi at the shift, IAC is 39 counts with 25* of timing 11.6-12.0 A/F ratio. At 100% throttle, it plateaus and stays at 6-6.5 psi throughout the entire rpm range. It does make it to 7 psi around 5100-5150 rpms but falls right back to 6-6.5 as rpms go over 5100, timing is 24* and fuel is 11.3-12.0.

Also, I have belt slip now when I didn't the first time and the belt is tighter than it was the first time as well. Belt is a Goodyear Gatorback. Could boost be stacking in the engine from an over sized throttle body? Doing the math, I should be flowing around 1100 cfm at 6300 rpms but I haven't been able to push it past 5500rpm at WOT as the truck doesn't feel good and is slower than at 57% TPS. I didn't have any belt slip issues when it was loosing boost so it seems like there is some sort of build up of pressure causing the Procharger to work harder and slip the belt.

So, just trying to get some thoughts here:
A) Do I pulley up to my 4.25 that I have laying around and see if that helps as I have a belt for that one.
B) IAC counts are 39 at WOT....is that throwing off the engine/supercharger working for boost?
C) With belt slip, do I have boost stacking from the Procharger working too hard or still have some sort of restriction still? (Treadstone TR1045 intercooler and AEM 6" x 14" long filter on the flange)
D) The headers don't clear the exhaust ports all the way on the AFRs, could that be causing some of this issue?

Thanks for the help as always!

YenkoST

iTrader: (5)

Back with more information. I put the 4.25 pulley on it and topped out at 125 map which is about 3.3 psi and by 4800 it was dying back off and by 5100rpms, the boost was gone. The top end just doesn't feel good in the engine. At 61% throttle, it went 48-92 mph in 8.5 seconds. Fuel was a tad lean. At 100% throttle, it went 60-109 in 11 seconds. No belt slip on these runs is found on the pulley or bracket.

With the 4.00 pulley on, I can say that 57% throttle according to the scanner was a significant improvement over 100% throttle.

Street Lethal

iTrader: (16)

Remember that boost is just a resistance measure. Using the 4.25 pulley, your seeing more resistance at lower TPS% creating more boost pressure, then the engine simply wakes up above 5000-RPM with that GM 847 camshaft, and remember that those cams can pull to 7000-RPM no problem, they make their power up top, so less resistance for the blower up there. The supercharger will just force whatever air that it does, but depending on how efficient your engine is at a particular RPM, and which pulley your running, will determine the boost pressure reading itself. Your engine seems too efficient for that 4.25 pulley up top, if you want to see sustaining boost pressure than you need a pulley that can follow through and keep ahead of that camshaft. The 4.00 pulley is allowing the blower to compressor more air at 57% throttle than the 4.25 pulley, but again, even at 100% throttle, it cannot really keep up with the engine. Two options here in my opinion, get a smaller camshaft to allow the 4.25/4.00 pulley to follow through, or keep the camshaft and run a 3.85/3.70 pulley...

DIGGLER

iTrader: (1)

Im still thinking belt slip. That or the blower swallowed a wrench at some point. Or a leak, but I would think you would hear some serious wooshing under the hood. I would think that pulley arrangement would put you well over 10psi regardless of what cam is in there.

Street Lethal

iTrader: (16)

A procharger does not have as great of a linear flow when compared to a turbo charger, and as RPM increases, the engine's naturally aspirated linear flow increases automatically with the result being a loss of boost resistance if the supercharger cannot keep up with that flow. If you calculate impeller speed and cfm at 8 pounds of boost pressure for a D1SC, with its' max impeller speed being 62,000 RPM, max flow at 1400-cfm, and max boost pressure at 32-psi, you will get a rough estimate as to how much cfm he is flowing at that boost pressure, then you calculate the engine's naturally aspirated cfm using data from the log, and you will see why he is losing resistance using that large of a diameter pulley when he reaches that RPM...

DIGGLER

iTrader: (1)

If it was making the power it should, I just cant see how he could be complaining. The truck should be destroying the tires at will.

DIGGLER

iTrader: (1)

http://m.youtube.com/?#/watch?v=nv7YWJRc84I

Watch his boost gage. That is what I would expect to see on this engine, too.

Street Lethal

iTrader: (16)

Mind you, every engine is of course different, and this is just a rough estimate. But just for the sake of conversation, if the D1SC is making 32-psi at 62,000 RPM and flowing 1400-cfm, then at 8-psi the procharger is spinning 15,500 RPM and flowing 350-cfm. If you calculate cfm per horsepower assuming he is making about 415 horsepower naturally aspirated at 4800-RPM, you get approximately 203 cfm beginning at that 4800-RPM mark, and that cfm will continue to rise on its' own naturally aspirated with RPM because that cam will pull to 7000-RPM, even w/out the supercharger. His engine is built extremely well for what it is. Above that 5000-RPM mark when he see's a decrease in boost pressure, he may be closing in on 500 horsepower naturally aspirated, which is roughly 250 cfm, and again, that is a rough estimate. Do you now see why boost pressure will decrease as RPM continues to rise using too big of a pulley with an engine that runs very efficiently up top on its' own...

YenkoST

iTrader: (5)

I have a buddy with an 8-rib 3.70 pulley that I can borrow for a run or two. If that is truly the problem, then I have no problem throwing 5 gallon of race fuel in it just to help slow down detonation with each tank with that level of boost. I really wouldn't think it would plateau like that with a 4.00 pulley as it should be increasing but it still has a problem past 5100 eventhough the boost is still there with the 4.00 pulley. With the 4.00 pulley, I'm flatlining at 6.5psi at 5100 rpms but I understand what you are saying about the powerband becoming more efficient in the camshaft. My last pull with the 4.00 pulley before installing the 4.25, the belt did slip on that one and have rubber on my bracket from that pull. When I went to the 4.25 pulley, I made 2-3 psi and it dropped off to 97 kpa on the top end.

However, that still does not explain why the truck runs better at 57-61% throttle than 100% throttle and does not breakup even with the engine pulling to 6k on both when both are losing boost/plateauing in boost. To me, it has to do with load on the engine whether its ignition or valve float, etc.

But, that's why I'm here to get some feedback and bounce some ideas back and forth.

YenkoST

iTrader: (5)

I did have some belt slip on one of the passes than the others but the boost remained the same on that one pass as it did on the others.

I hear the BOV relieving pressure when I close the throttle as I did that just to make sure. Let out of it around 5100 and it let off when I let of the throttle.

Other than that, I don't hear any rushing air. Engine sounds clean and crisp but after 5100...starts to stutter some and not pull clean.

YenkoST

iTrader: (5)

I've done those calculations, I have it at home. 4.25 pulley is around 1050 cfm at 6300 rpms while the 4.00 pulley is around 1110 cfm at 6300. I haven't been able to get up to those rpms yet

With the 4.00 pulley, the D1SC is turning about 46,8xx @6000 rpms and 492xx @6300 rpms with an internal step of 4.10.

Formula I found to calculate all this with is:
Impeller RPM = (Crank Pulley Diameter/Blower Pulley) x Internal Step Ratio x Engine RPM

Engine CFM = (CID x RPM) / 3456 x ((PSI/14.7)+1)

Max Boost = (14.7 psi x S/C cfm) / Engine CFM

YenkoST

iTrader: (5)

And that's the problem...it's not....

When it downshifts from 4->1 and gets in about 5000rpms...the truck just slowly increase mph but once it shifts, it's gone until about 5100 again then dies off.
Link doesn't work for me?

Street Lethal

iTrader: (16)

For the supercharger to maintain 8-psi throughout the RPM band, t4he linear flow from both the supercharger as well as the engine, needs to remain the same. The engine's linear flow alone will increase as RPM increases with a supporting camshaft. Putting aside boost resistance measures, valve float will cause the RPM to become stagnent, and that engine should pull well above 6000-RPM on its' own, and if boost drops, but RPM increases, then it becomes a matter of the loss of linear flow on the supercharger's part and not valve float. Only fix is a bigger F1 series, or smaller pulley for the D1SC. Definitely try a smaller pulley, as your engine is no slouch naturally aspirated. Put that same D1SC setup of yours on any L98 in this forum and that linear flow will remain constant on both sides, in fact, you will see more than 8-psi with that same pulley on any L98 because they simply can't breath up top, which is a restriction, and boost is a restriction measure...

Street Lethal

iTrader: (16)

Have you considered that you might be blowing through your stall converter? Your datalogs do not lie, your power is there, but if the converter isn't holding, your not going anywhere...

Street Lethal

iTrader: (16)

How is the ignition system itself, coil, wires, etc, all good...?

YenkoST

iTrader: (5)

Could be I guess but it doesn't like it as it not going to the rev limiter at all but I know that's not the case in all situations. Its an Edge 3400 brand new built by Andre. Its his top of the line version Pro Edge.

DIGGLER

iTrader: (1)

without trying to explain anything, a d1sc on this engine should be making 550+ at the wheels at least. if it had a boost gauge, it should climb until the shift point. just going off of most all the other d1sc combos out there. gm847 is not a "big" cam compared to race stuff.

if its actually breaking up, i would think tuning or ignition? is the map sensor accurate?

YenkoST

iTrader: (5)

Pretty much all new...wires are about 5 years old but have less than 5k miles on them. Plugs are brand new. Crane ignition box is about 3 years old as well as the coil. The ignition module is brand new in the distributor but I'm going to try the 369 module back in it just in case.

YenkoST

iTrader: (5)

MAP sensor is new. I can try switching it out for a 3 bar that I have laying around but all seems good.

I would think so as well that with this engine that I would be pushing 550rhwp+ as well. Was hoping for 625-650rwhp (mid-10s in the 1/4).

I'll try and grab a boost gauge and read it and see what I get if a few others things I'm going to try doesn't work out.

Tune looks great...A/F ratio is in line, timing is good, plugs have no detonation on them, etc. I'm going to check ignition as it could be the brand new DynaMod that I just installed in place of the 369 module.

Street Lethal

iTrader: (16)

Your not listening lol. Stop arguing, let it seep in..

If he is making close to, if not more than 500 horsepower on the engine alone after 5000-RPM and up, and the D1SC is good for 550 at 8-psi, then how much boost pressure do you think it will take to make that extra 50 horsepower? Superchargers are not turbo's, turbo chargers have continual linear boost because they have much higher RPM capability not to mention wastegate control to keep it at 8-psi. A blower's linear flow will drop if the engine is making enough power up top (cfm) unless you put a pulley on it that overcomes any linear flow loss.

DIGGLER

iTrader: (1)

Blowing through the converter would act like it zips to a high rpm and stays there until you let out. Shifts wont change rpms much if any.

DIGGLER

iTrader: (1)

Looking back at your other thread, you posted a log with air flow.... are you running a maf?

YenkoST

iTrader: (5)

Yeah, its not blowing through the converter.....it is increasing in rpms and shifts brings it down about 1000 rpms or so.

YenkoST

iTrader: (5)

Negative, Speed Density.

DIGGLER

iTrader: (1)

How much power is he making?

Street Lethal

iTrader: (16)

No no, I meant blowing through the converter down low from the heavy load and off idle blip because the two of you were stating that the vehicle should be blowing the tires away when it isn't. The converter is definitely coupling where it seems to be flashing from the log. Don't forget that his timing is still on the conservative side, as I had it set for 36* total in that bin that I sent him, and I lowered it only 1 degree per every 1-psi of boost, but he is running less total though, and is pulling more than 1 degree of timing for every pound of boost made. His Launch Mode might need a little bit of tweaking as well, I remember having loads of fun one night on the highway trying dial in PE and Launch SA...

I had him well over 400 horsepower naturally aspirated at around the 5000-RPM mark, and I that number will go up substantially when/if he revs it past 6000-RPM, because the cam and those heads want that, but regardless if the timing isn't there, he is holding himself back...

DIGGLER

iTrader: (1)

so what is the answer here?

DIGGLER

iTrader: (1)

street, i really am trying to listen to what your saying.... but in my mind i know that a d1sc on a 383 with a great pair of heads like he has should be making fantastic power. probably 600whp or 700 flywheel. you are saying the power is being made, yet he is experiencing lackluster results.

is this car using enough fuel to indicate that its producing 650-700 flywheel horsepower?

DIGGLER

iTrader: (1)

here is a dyno of a 347 ford with a d1sc. look and see what his boost numbers were on the dyno readout.... made more and more boost every step of the way. i believe they have an 8" lower, so it spins a bit faster. over 18 psi of boost. steve mentioned that with the old cam profile the boost was 4psi higher, so a previous dyno would have been 22psi.
they are making well over 800 flywheel with this blower on a street motor.

Street Lethal

iTrader: (16)

The answers are in the datalog, the math doesn't lie...

You are not listening. Again, he is only running an 8-psi pulley, and you stated yourself that a D1SC at 8-psi should be good enough for 550 horsepower. It doesn't matter what engine the D1SC is on, as it is belt driven, and it puts out a FIXED amount of air at a particular RPM, do you agree? Depending on how efficient the engine already is, meaning how much cfm it flows on its' own, will determine the amount of boost pressure the D1SC is making. If you put a D1SC with 4.25" pulley on a 347 Ford that flows less naturally aspirated at 5000-RPM, the D1SC will make a certain amount of boost at that RPM, if you put that same D1SC and pulley on a 383 Chevy that flows more naturally aspirated at 5000-RPM then that same D1SC will make less boost at that RPM, if you put that same D1SC with pulley on a 572 big block chevy that flows a great deal more air on its' own, the D1SC with 4.25" pulley will make even less boost, or hardly any boost for that matter at that same RPM. Again, superchargers are not turbo's, turbo's spin fast enough to maintain a predetermined boost pressure. Supercharger's on the other hand need to overcome the engine's naturally aspirated linear flow, and if it can't, then the pulley is too big, or the supercharger itself is too small...

Did you even listen to what Steve was saying in that video? The cam was the cause of 4-psi drop in boost pressure and made 40 horsepower more overall. Why? Because the engine is now breathing better on its' own (linear flow). This is exactly the case with Yenko, as his setup is advertised (for the average street engine) for 8-psi using that pulley, but his engine is not the average street engine, thus the pulley dropping from advertised psi. Don't you see yet? Yenko is losing the boost pressure, but is making the right power. Think of it this way Dig, and this is just for the sake of conversation. Lets just say that Yenko's engine was only making 367 horsepower at 6000-RPM with his setup, and that D1SC w/pulley was good for 550 horsepower. Now, at 6000-RPM, he would be making 8-psi and the boost gauge would be reading 8-psi for a total of 550 horsepower. Now, let's up that same engine's naturally aspirated linear flow. Using the same D1SC and pulley that is good for 550 horsepower, let's say Yenko's engine was making 450 horsepower at 6000-RPM naturally aspirated. The difference between that 450 naturally aspirated horsepower and that 550 D1SC w/pulley horsepower in terms of boost pressure in itself is only about 3.5-psi of boost pressure. Again now, think. If the pulley is good for 550 horsepower, and the engine is already making 450 horsepower in this scenario, why would the boost gauge be reading 8-psi when it is only contributing 3.5-psi of air at that point totaling 550 horsepower? Again, superchargers are not turbo's, supercharger's can't maintain 8-psi if the engine's naturally aspirated linear flow exceeds a particular threshold. Do you get it yet?

DIGGLER

iTrader: (1)

Nope. Lol. I guess there isnt a problem at all.

Street Lethal

iTrader: (16)

Think carefully now. These are the numbers from Steve Morris...;

555 Horsepower @ 9-psi
675 Horsepower @ 11-psi
789 Horsepower @ 13-psi
814 Horsepower @ 15-psi

Judging from these numbers, Steve's test engine running the D1SC is making the following naturally aspirated horsepower at the crank (see bold)...

09-psi = 63%, 63% of 340 = 214, 340 + 214 = 554 Horsepower @ 4400-RPM.
11-psi = 77%, 77% of 380 = 292, 380 + 292 = 672 Horsepower @ 4900-RPM.
13-psi = 91%, 91% of 413 = 375, 415 + 377 = 788 Horsepower @ 5500-RPM.
15-psi = 100% 100% of 407 = 407, 407 + 407 = 814 Horsepower @ 5700-RPM.

At this point, there are two things to consider. One, Yenko's engine will make more horsepower throughout the RPM band if he not only revs it up to and over 6000-RPM, but also runs the correct crank and supercharger pulley allowing him to reach 15-psi of boost pressure, and two, Steve did not relegate himself to an advertised 8-psi pulley, he is running the correct pulleys to overcome the engine's naturally aspirated linear flow to allow the D1SC to be able to overcome and reach 15-psi. Again, Yenko is only running an 8-psi pulley, so how do you expect Yenko to see 15-psi like Steve Morris? Using a Steve Morris video showing him reach 15-psi is not only not accurate, it just underlines that Yenko needs more pulley. At 15-psi Yenko will be way over 800 RWHP, and Yenko's engine will make way more naturally aspirated crank horsepower than that engine in the video...

Edit: Your comparing an 8-psi pulley setup to a 15-psi pulley setup, there's the "problem"...

DIGGLER

iTrader: (1)

What I was trying to show is the boost was gaining with rpm. The whole way.
You have explained everything else, now can you explain to the op why his truck is slower than it should be with these pulleys? Or why it doesnt want to pull past 5k?

Street Lethal

iTrader: (16)

I took the time and did the math, and the math does not lie. If you honestly think that a Procharger 8-psi advertised pulley will somehow and magically make 15-psi then I don't know what to tell you, because the very fact that you can post a Steve Morris video showing 15-psi while comparing it to Yenko's 8-psi pulley setup trying to imply that Yenko should also be seeing the same numbers as Steve Morris completely throws your argument out of the window. Yenko is running an 8-psi pulley, and the more the engine revs, the more the linear flow the engine will be able to take in all on its' own. You are completely confusing yourself, superchargers are not turbo's, superchargers give up the ghost once they max themselves out depending on the pulley setup and they will LOSE boost pressure as the engine is able to consume more and more air on it's own while RPM increases, which is what any ordinary engines will do, especially one built to make power up to 7000-RPM. The math does not lie. I mean for Christ's sake, by your understanding, why have a pulley chart lol? Why not just buy an 8-psi rated pulley and magically get it to 15+psi like Steve Morris...

Street Lethal

iTrader: (16)

Again Dig, his horsepower is there as per the datalog. Why not ask Yenko to do a 1/4 analysis on the WUD, as the EBL-P4 tracks all of that data, sixty foot, 1/8th, 1/4, etc, and THEN we'll determine what the problem is by calculating his ET, speed, and weight...

YenkoST

iTrader: (5)

Ok, last night, spent a few hours doing odds and ends to the truck. I put the 369 module back in the distributor cap and also put a new button on the rotor as well since I was in it again, I thought might as well. Cleaned the cap and put everything back together. I put the 4.00 pulley back on it with a new belt. Had to get one as the other went over the crank. I spaced the Procharger back .070" so I'll see if that'll fix that issue...it just started trying to come over the front of the crank pulley for some strange reason.

Anyways, I have a new tune ready to roll. I'm a little more aggressive with the timing. I listened to the video from Steve that said that if you didn't have enough timing that power would flat line but boost would still build. So, I'm at 30* of timing at WOT and then pulling about 1.5 degrees per 10kpa increase which I know is a little bit safe but I want to be safe until I get it resolved and then have two tunes. A street tune and a track tune.

Also, had another person say that my headers could be restricting a bit since they aren't fully open at the exhaust port but said that would be restricting total hp and not boost, etc and that would rather build more boost as boost would "stack" and not be able to exit fast enough. So, I might be upgrading to 1 7/8" soon. I'm hopefully going to a dyno in the next few weeks if I can't get it running right to see if the power is just falling off or plateauing. I'd like to take it to the track over x-mas break and get some nice 6 sec passes in 1/8th mile.

DIGGLER

iTrader: (1)

How much hp is he making. Give me a number. At 6000 or whatever his highest datalog went.

92RSZ

iTrader: (6)

You've either got belt slip, a boost leak, or something wrong with that blower. I've got a d1sc on a much bigger engine (420), with much bigger heads (220cc), and a bigger cam (242/242 at .050). I'm running a 7.65 crank/4.25 blower pulley and it makes 7 psi at 6800rpm. Dyno'd 550 horsepower n/a so it's pretty efficient. Prochargers are very linear as the boost climbs throughout rpm with no drop. I had some belt slip and experienced boost dropping until I tightened it up.

DIGGLER

iTrader: (1)

Thank you!

DIGGLER

iTrader: (1)

Blower bracket may be flexing if pulleys are dead straight. This would also explain how it could be slipping.

YenkoST

iTrader: (5)

Yeah, the belt started to go over the crank pulley randomly the other day with the 4.25 pulley so I spaced it back another .070 to see if that will fix the issue and put a brand new belt on it as well.

Another idea I had is put a tensioner on the bracket like a few have done on here...that would eliminate the belt slip question.

junkcltr

iTrader: (1)

I am surprised the blower companies don't have a bolt on VR or hall effect sensor setup so the RPM can be recorded and compared to crank RPM. Dump the signal into an arduino or something simple like that and it could calculate the compressor RPM.

Overall, to me it sounds like belt slip.

Street Lethal

iTrader: (16)

Why would you be thanking him? He stated he thinks its either belt slip, a boost leak or there is a problem with the head unit. Original poster stated he has no belt slip issues, and has triple checked for boost leaks. As for a problematic head unit, that is still up in the air...

As for the other member's setup, his claim of a 4.25 pulley which is rated for only 8-psi as per Procharger themselves is making 7-psi of boost pressure with his engine that is already making 550 horsepower naturally aspirated at 6800-RPM using a D1SC and 7.65 crank pulley. This would imply that his engine is making approximately 825 Horsepower using a 4.25/7.65 pulley combo with the D1SC putting out 7-psi at 6800-RPM, a horsepower number which he failed to mention. Interestingly enough, 925 Horsepower is rated as the "max" for the D1SC, yet somehow 825 is achieved with only an 8-psi rated 4.25 pulley that is making 7-psi, which is on target, on a 550 NA horsepower engine using a 7.65 crank pulley. I guess Procharger has their facts wrong, because interestingly enough, the smaller 3.40 pulley used with the 7.65 crank pulley should put out over 15-psi with that same setup, and this would mean that his 550 horsepower engine using the same combo but with 3.40 pulley will make over 1100 Horsepower with that same D1SC that is capped at 900 horsepower for the rest of the entire planet. I obviously don't believe that claim whatsoever simply based on that fact alone, but I digress...

Yenko, get a 1/4 analysis on the WUD, that will tell everyone everything...

92RSZ

iTrader: (6)

You seem to be stuck on psi which is nothing but measure of restriction. Prochargers boost ratings in this application are for tpi motors that don't rev past 5500rpm. Impeller rpm is what is important for cfm. My combo puts impeller rpm at 50,000 max rpm which is ~1100 cfm. If 1400 cfm equals 925 horsepower, 1100 is around 750 which is pretty close to what my car makes. I never dyno'd it after I put the blower on, but it runs 130 in the 1/4 at 3700 race weight. I had no dust when my belt was slipping, but it was slipping.

DIGGLER

iTrader: (1)

I thanked him for simply adding his factual data and experience. And for stating that the boost should not be falling off like you have explained.

DIGGLER

iTrader: (1)

Max hp ratings dont mean much either. Guys have made 1200+hp with vortech ysi's.

YenkoST

iTrader: (5)

Well, I was tearing into the truck today and noticed the engine belt was hitting the spacer just under the alt. So, going to go some work on that. I posted a picture of that as well as put a spring tensioner on the supercharger belt to solve any slippage issue that I could possibly have. I also posted a pic of the spark plug.

Street Lethal

iTrader: (16)

Gonna explain this one last freaking time and then I am done. Anyone who thinks that a D1SC running a 4.25" pulley and 7.65" crank pulley that PEAKS at 8-psi on an engine that has a BASE horsepower level of 300 horsepower, with 8-psi bringing that 300 Horsepower engine to 450 horsepower (8-psi is 56% increase), while at the same time believes that the SAME D1SC running the SAME 4.25" pulley and 7.65" crank pulley will also MAKE 8-psi on an engine that has a BASE horsepower level of 500 horsepower is freaking smoking crack! A D1SC with that 7.65/4.25 pulley combo only puts out X amount of air REGARDLESS of the engine, period, end of discussion, and boost pressure will VARY depending on the base horsepower, so don't expect ADVERTISED psi ratings...

Yenko, best of luck with the build...

[/done]

DIGGLER

iTrader: (1)

i am hard headed too, but wow.
d1sc on stock tpi ~5000 rpms 7.65/4.25 = 8psi
d1sc on same engine with single plane/cam ~6000 rpms 7.65/4.25 = 10psi

why? for every engine rotation, the impeller is turning 8 times. spin the engine 1000 more rpms and the blower will turn 8000 more rpms.

DIGGLER

iTrader: (1)

engine hp doesnt matter either.
stock tpi with d1sc ~5000 rpm = 8psi
stock tpi with d1sc and 1 plug wire unhooked ~5000 rpm = 8psi