D1 Procharged L98 Design Excersise...
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D1 Procharged L98 Design Excersise...
Good news, it appears ATI's CARB# finally went through last December, so apparently 91 and older L98 Vettes can legally run a Procharger in CA.
Ok, here's a design excersise (Plan A)...
A) Hoping to make a Procharger Kit bulletproof on a near stock cast piston'd Speed Density L98. Expecting about 425HP at the crank with a stock 91 L98 (excepting ported Saimesed Runners and a Big Base Manifold, bigger Injectors and Fuel Pump, with a revised injector constant ond offset PROM).
B) Will have to run a D1 Compressor for FX3 Electronic Shock Actuator clearance (it appears that the bigger D1 is the only Procharger that'll clear the stock electronic shock actuator, as it's bigger transmission moves the main body slightly rearward, there by allowing clearance with a lightly modified bracket).
C) I'll likely have to run the FMU for smog checks at minimum, but was thinking that perhaps at this mild power level it might be ok as...
1) I won't be tuning for max power with cast pistons anyway, so as long as I'm safely way phat what's the difference?
2) The FMU's fuel pressure increase allows me an easy way to reference an electronic control valve as a safety measure.
To this end then...
A) Pulley the D1 at 10PSI @ 5700 rpm (redline and fuel cutoff).
QUESTION: Will the L98's pulley arrangement allow a D1 to make 10PSI without slipping?
B) Upgrade the intank Fuel Pump rather than the T-Rex (should be quieter and safer using the factory harness).
C) Use an inexpensive mechanical BOV (post IC), to limit boost to a cast piston friendly 7 PSI (should improve the low-end and midrange while protecting from over-revving, and provide a roughly 50% power increase).
D) Incorporate an Electronic Control Valve referenced to Boost and Fuel Pressure Switches like this...
IF (Post IC Boost > 3PSI) AND (Fuel Pressure > 55PSI)
#Assuming a 4:1 FMU and stock fuel pressure.
THEN (Close Valve/Don't get a ticket)
ELSE (Open Valve/Vent Boost to atmosphere)
This protects from many Fuel Pump and FMU failures to some degree (valve opens and vents boost in a few milliseconds).
QUESTION: What kind of CFM would this valve have to flow to vent roughly 4PSI of boost (the difference between the 3PSI Pressure Switch Threshold, and the 7PSI BOV)?
I'm guessing that 150cfm would cover it, like...
(NA 350ci @ 5700 WOT = roughly 550cfm)
(7PSI = .5 atmosphere for another 275cfm at 5700 WOT / 2 = 135 cfm)
QUESTION: How wrong am I?
The Compressor Discharge Tract is then populated with these three controls (not counting the Intercooler of course)...
A) A post IC Bypass Valve plumbed back to the Air Cleaner to avoid surge (opens with vacuum).
B) A post IC BOV (plumbed back to the Air Cleaner, opens under high boost to limit boost).
C) A 12V Control Valve (opens under boosts greater than 3PSI along with inadequate fuel pressure to vent boost).
Ok, what do Ya'll think?
Thanks...
Doug
Ok, here's a design excersise (Plan A)...
A) Hoping to make a Procharger Kit bulletproof on a near stock cast piston'd Speed Density L98. Expecting about 425HP at the crank with a stock 91 L98 (excepting ported Saimesed Runners and a Big Base Manifold, bigger Injectors and Fuel Pump, with a revised injector constant ond offset PROM).
B) Will have to run a D1 Compressor for FX3 Electronic Shock Actuator clearance (it appears that the bigger D1 is the only Procharger that'll clear the stock electronic shock actuator, as it's bigger transmission moves the main body slightly rearward, there by allowing clearance with a lightly modified bracket).
C) I'll likely have to run the FMU for smog checks at minimum, but was thinking that perhaps at this mild power level it might be ok as...
1) I won't be tuning for max power with cast pistons anyway, so as long as I'm safely way phat what's the difference?
2) The FMU's fuel pressure increase allows me an easy way to reference an electronic control valve as a safety measure.
To this end then...
A) Pulley the D1 at 10PSI @ 5700 rpm (redline and fuel cutoff).
QUESTION: Will the L98's pulley arrangement allow a D1 to make 10PSI without slipping?
B) Upgrade the intank Fuel Pump rather than the T-Rex (should be quieter and safer using the factory harness).
C) Use an inexpensive mechanical BOV (post IC), to limit boost to a cast piston friendly 7 PSI (should improve the low-end and midrange while protecting from over-revving, and provide a roughly 50% power increase).
D) Incorporate an Electronic Control Valve referenced to Boost and Fuel Pressure Switches like this...
IF (Post IC Boost > 3PSI) AND (Fuel Pressure > 55PSI)
#Assuming a 4:1 FMU and stock fuel pressure.
THEN (Close Valve/Don't get a ticket)
ELSE (Open Valve/Vent Boost to atmosphere)
This protects from many Fuel Pump and FMU failures to some degree (valve opens and vents boost in a few milliseconds).
QUESTION: What kind of CFM would this valve have to flow to vent roughly 4PSI of boost (the difference between the 3PSI Pressure Switch Threshold, and the 7PSI BOV)?
I'm guessing that 150cfm would cover it, like...
(NA 350ci @ 5700 WOT = roughly 550cfm)
(7PSI = .5 atmosphere for another 275cfm at 5700 WOT / 2 = 135 cfm)
QUESTION: How wrong am I?
The Compressor Discharge Tract is then populated with these three controls (not counting the Intercooler of course)...
A) A post IC Bypass Valve plumbed back to the Air Cleaner to avoid surge (opens with vacuum).
B) A post IC BOV (plumbed back to the Air Cleaner, opens under high boost to limit boost).
C) A 12V Control Valve (opens under boosts greater than 3PSI along with inadequate fuel pressure to vent boost).
Ok, what do Ya'll think?
Thanks...
Doug
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Joined: Feb 2002
Posts: 11,268
Likes: 14
From: Honolulu, HI
Re: D1 Procharged L98 Design Excersise... (doug_dayson)
Wow. That's a lot. Well, I would consider myself relatively new to this so take what I have to say with a grain of salt.
A) 425 HP to the crank shouldn't be hard especially with 10 psi, but personally, I think 10 psi is too much for the stock comp ratio, depending at what altitude you are at (see Krivera)
B) I'm sure Blackbart will chime in, because he's running a D1-R with FX-3 just fine, so you should be o.k. (In fact, there was a recent thread on this topic)
C) I still am getting conflicting views on the FMU situation. Best thing to do is get bigger injectors, fuel pump, and tuned ECU, run the FMU and do some scanning. Then use the FMU to add or remove fuel if necessary.
1) If 425 HP is what you're after, you'll be fine. I've heard anything over 500HP is detremental.
2) I like this idea of venting boost based on fuel pressure. However, if you have your chip tuned properly with proper injectors and fuel pump, you don't necessarily have to rely on your FMU. But it's not a bad idea anyway. Let me know what hardware you're using to do this :cheers:
A) find out what other people at about your altitude think about 10psi on a stock L98.
B) DEFINITELY upgrade your fuel pump. Don't rely on the Aux. pump from ATI. check out http://www.racetronix.com for their complete kit. You don't want to plug into your stock harness. Their special harness plugs right into the back of the alternator giving 14 volts, instead of the 12.5 or 13 out of the stock harness. This directly translates to volume at the pump. (it's also a snap to install)
C) Hmmm, I would think running a BOV post IC would definitely be more accurate at relieving just enough boost due to the possible pressure drop once it hits the manifold. Depends on what the BOV it made to pop at I guess. Let me know how you set this up too :cheers:
D) Let me know what this is?
As far as the BOV, I'm not sure about CFM, but Blackbart runs a wastegate.....YES a wastegate that relives excess manifold pressure. If you're nice to him, and serious about doing it, he just might tell you how he did it :D
:cheers:
A) 425 HP to the crank shouldn't be hard especially with 10 psi, but personally, I think 10 psi is too much for the stock comp ratio, depending at what altitude you are at (see Krivera)
B) I'm sure Blackbart will chime in, because he's running a D1-R with FX-3 just fine, so you should be o.k. (In fact, there was a recent thread on this topic)
C) I still am getting conflicting views on the FMU situation. Best thing to do is get bigger injectors, fuel pump, and tuned ECU, run the FMU and do some scanning. Then use the FMU to add or remove fuel if necessary.
1) If 425 HP is what you're after, you'll be fine. I've heard anything over 500HP is detremental.
2) I like this idea of venting boost based on fuel pressure. However, if you have your chip tuned properly with proper injectors and fuel pump, you don't necessarily have to rely on your FMU. But it's not a bad idea anyway. Let me know what hardware you're using to do this :cheers:
A) find out what other people at about your altitude think about 10psi on a stock L98.
B) DEFINITELY upgrade your fuel pump. Don't rely on the Aux. pump from ATI. check out http://www.racetronix.com for their complete kit. You don't want to plug into your stock harness. Their special harness plugs right into the back of the alternator giving 14 volts, instead of the 12.5 or 13 out of the stock harness. This directly translates to volume at the pump. (it's also a snap to install)
C) Hmmm, I would think running a BOV post IC would definitely be more accurate at relieving just enough boost due to the possible pressure drop once it hits the manifold. Depends on what the BOV it made to pop at I guess. Let me know how you set this up too :cheers:
D) Let me know what this is?
As far as the BOV, I'm not sure about CFM, but Blackbart runs a wastegate.....YES a wastegate that relives excess manifold pressure. If you're nice to him, and serious about doing it, he just might tell you how he did it :D
:cheers:
Thread Starter
Pro
Joined: May 2002
Posts: 518
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Re: D1 Procharged L98 Design Excersise... (vvv90)
Wow. That's a lot. Well, I would consider myself relatively new to this so take what I have to say with a grain of salt.
*I'm new to Forced Induction too, and thanks for your time!
A) 425 HP to the crank shouldn't be hard especially with 10 psi, but personally, I think 10 psi is too much for the stock comp ratio, depending at what altitude you are at (see Krivera)
*There's no way a stock L98 could survive 10PSI at sealevel!
*I was only thinking that the D1 could not be pulley'd down lower than 10PSI, so the BOV would pop off at 7PSI (for the cast piston's sake).
B) I'm sure Blackbart will chime in, because he's running a D1-R with FX-3 just fine, so you should be o.k. (In fact, there was a recent thread on this topic).
*Yes, he has, and many thanks to him!
*I love the FX3 with the Z51 springs...
C) I still am getting conflicting views on the FMU situation. Best thing to do is get bigger injectors, fuel pump, and tuned ECU, run the FMU and do some scanning. Then use the FMU to add or remove fuel if necessary.
*I believe it's best to eliminate the FMU and tune the PE Tables accordingly, though I'll need the FMU operating to smog it etc. Since it would have to be installed at any rate, I was thinking that perhaps I could put it to use?
1) If 425 HP is what you're after, you'll be fine. I've heard anything over 500HP is detremental.
*I'm trying to be conservative to start out, and I'll likely build a proper forged short block down the road etc.
2) I like this idea of venting boost based on fuel pressure. However, if you have your chip tuned properly with proper injectors and fuel pump, you don't necessarily have to rely on your FMU. But it's not a bad idea anyway. Let me know what hardware you're using to do this :cheers:
*I haven't sourced parts yet, but the Control Valve would be similar to these...
http://www.thevalveshop.com/menu/aut...burkertsv.html
...and the pressure switches can be had from Carroll Supercharging among others.
A) find out what other people at about your altitude think about 10psi on a stock L98.
*I'm only looking at 7PSI thanks to the BOV, though the boost should come on 500 to 1000 rom earlier I'm hoping...
B) DEFINITELY upgrade your fuel pump. Don't rely on the Aux. pump from ATI. check out http://www.racetronix.com for their complete kit. You don't want to plug into your stock harness. Their special harness plugs right into the back of the alternator giving 14 volts, instead of the 12.5 or 13 out of the stock harness. This directly translates to volume at the pump. (it's also a snap to install).
*Volume won't be an issue with a mild 425HP at the crank, so any of the intank upgrades should be fine at this power level.
C) Hmmm, I would think running a BOV post IC would definitely be more accurate at relieving just enough boost due to the possible pressure drop once it hits the manifold. Depends on what the BOV it made to pop at I guess. Let me know how you set this up too :cheers:
*Not sure myself, though Black Bart is doing something similar, so I'll search the archives.
The cheap mechanical BOV's are just spring loaded as far as I know, thought the electronic Boost Controllers for Turbos Wastegates actually run in a closed loop fashion, with the Wastegate being Pulse Width Modulated via a MAP Sensor, and they can maintain a commanded pressure, so that's where my search will start.
D) Let me know what this is?
As far as the BOV, I'm not sure about CFM, but Blackbart runs a wastegate.....YES a wastegate that relives excess manifold pressure. If you're nice to him, and serious about doing it, he just might tell you how he did it :D
Yes, if someone has already made this work for a Centrifugal I'm all ears!
*To my mind, it shouldn't make much difference if the wastegate is venting exhaust or manifold pressure (that's if it's fast enough, and aside from the temperature differences of course), but I'm only speculating...
If this could be done with a Boost Controller and Wastegate, then perhaps the BOV would not be needed?
Thanks again...
Doug
:cheers:
*I'm new to Forced Induction too, and thanks for your time!
A) 425 HP to the crank shouldn't be hard especially with 10 psi, but personally, I think 10 psi is too much for the stock comp ratio, depending at what altitude you are at (see Krivera)
*There's no way a stock L98 could survive 10PSI at sealevel!
*I was only thinking that the D1 could not be pulley'd down lower than 10PSI, so the BOV would pop off at 7PSI (for the cast piston's sake).
B) I'm sure Blackbart will chime in, because he's running a D1-R with FX-3 just fine, so you should be o.k. (In fact, there was a recent thread on this topic).
*Yes, he has, and many thanks to him!
*I love the FX3 with the Z51 springs...
C) I still am getting conflicting views on the FMU situation. Best thing to do is get bigger injectors, fuel pump, and tuned ECU, run the FMU and do some scanning. Then use the FMU to add or remove fuel if necessary.
*I believe it's best to eliminate the FMU and tune the PE Tables accordingly, though I'll need the FMU operating to smog it etc. Since it would have to be installed at any rate, I was thinking that perhaps I could put it to use?
1) If 425 HP is what you're after, you'll be fine. I've heard anything over 500HP is detremental.
*I'm trying to be conservative to start out, and I'll likely build a proper forged short block down the road etc.
2) I like this idea of venting boost based on fuel pressure. However, if you have your chip tuned properly with proper injectors and fuel pump, you don't necessarily have to rely on your FMU. But it's not a bad idea anyway. Let me know what hardware you're using to do this :cheers:
*I haven't sourced parts yet, but the Control Valve would be similar to these...
http://www.thevalveshop.com/menu/aut...burkertsv.html
...and the pressure switches can be had from Carroll Supercharging among others.
A) find out what other people at about your altitude think about 10psi on a stock L98.
*I'm only looking at 7PSI thanks to the BOV, though the boost should come on 500 to 1000 rom earlier I'm hoping...
B) DEFINITELY upgrade your fuel pump. Don't rely on the Aux. pump from ATI. check out http://www.racetronix.com for their complete kit. You don't want to plug into your stock harness. Their special harness plugs right into the back of the alternator giving 14 volts, instead of the 12.5 or 13 out of the stock harness. This directly translates to volume at the pump. (it's also a snap to install).
*Volume won't be an issue with a mild 425HP at the crank, so any of the intank upgrades should be fine at this power level.
C) Hmmm, I would think running a BOV post IC would definitely be more accurate at relieving just enough boost due to the possible pressure drop once it hits the manifold. Depends on what the BOV it made to pop at I guess. Let me know how you set this up too :cheers:
*Not sure myself, though Black Bart is doing something similar, so I'll search the archives.
The cheap mechanical BOV's are just spring loaded as far as I know, thought the electronic Boost Controllers for Turbos Wastegates actually run in a closed loop fashion, with the Wastegate being Pulse Width Modulated via a MAP Sensor, and they can maintain a commanded pressure, so that's where my search will start.
D) Let me know what this is?
As far as the BOV, I'm not sure about CFM, but Blackbart runs a wastegate.....YES a wastegate that relives excess manifold pressure. If you're nice to him, and serious about doing it, he just might tell you how he did it :D
Yes, if someone has already made this work for a Centrifugal I'm all ears!
*To my mind, it shouldn't make much difference if the wastegate is venting exhaust or manifold pressure (that's if it's fast enough, and aside from the temperature differences of course), but I'm only speculating...
If this could be done with a Boost Controller and Wastegate, then perhaps the BOV would not be needed?
Thanks again...
Doug
:cheers:
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: D1 Procharged L98 Design Excersise... (doug_dayson)
Running anything over 5-6 psi with cast pistons is just asking for trouble. I think most here have tried it. You will be rebuilding your motor- just a question of whether you want to do it now or next year after it self destructs...
That being said I like your idea of using a mech BOV that can be adjusted to limit boost. It should allow you to build more low-mid while keeping it from blowing up at redline; plus you could turn it up/down depending on gasoline quality, etc. Maybe a wastegate would work but I bet the pressure range from the hot exhaust is a lot higher than the 8-15psi in your intake.
Tying the pressure relief to fuel pressure sounds like a good safety measure; that's how I destroyed my first SC engine- the damn fuse blew on the ATI fuel pump and it went really lean with WFO throttle on the front straight.
And yes, FMU's suck wind! Run 36-50 lb/hr injectors with an ECM and programming that can handle it.
Superchargers are fun- I'm making 510 ft-lbs at the rear wheels with my lowly P600b... Good luck with your project :cool:
That being said I like your idea of using a mech BOV that can be adjusted to limit boost. It should allow you to build more low-mid while keeping it from blowing up at redline; plus you could turn it up/down depending on gasoline quality, etc. Maybe a wastegate would work but I bet the pressure range from the hot exhaust is a lot higher than the 8-15psi in your intake.
Tying the pressure relief to fuel pressure sounds like a good safety measure; that's how I destroyed my first SC engine- the damn fuse blew on the ATI fuel pump and it went really lean with WFO throttle on the front straight.
And yes, FMU's suck wind! Run 36-50 lb/hr injectors with an ECM and programming that can handle it.
Superchargers are fun- I'm making 510 ft-lbs at the rear wheels with my lowly P600b... Good luck with your project :cool:
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Pro
Joined: May 2002
Posts: 518
Likes: 17
Re: D1 Procharged L98 Design Excersise... (gcrouse)
Running anything over 5-6 psi with cast pistons is just asking for trouble. I think most here have tried it. You will be rebuilding your motor- just a question of whether you want to do it now or next year after it self destructs...
*Yes, I've decided to run and Intercooled or Water/Alcohol Injected 6PSI Max (limited by a Pop-Off/BOV/Wastegate Valve), figuring about a 40% gain. I think that if I keep the tune good and phat, the IAT's low, and the boost/cylinder pressure mild the cast pistons could have a fairly long life.
That being said I like your idea of using a mech BOV that can be adjusted to limit boost. It should allow you to build more low-mid while keeping it from blowing up at redline; plus you could turn it up/down depending on gasoline quality, etc. Maybe a wastegate would work but I bet the pressure range from the hot exhaust is a lot higher than the 8-15psi in your intake.
*Agreed...
Tying the pressure relief to fuel pressure sounds like a good safety measure; that's how I destroyed my first SC engine- the damn fuse blew on the ATI fuel pump and it went really lean with WFO throttle on the front straight.
Exactly the failure I'm trying to avoid, though if I dump the FMU and use the factory fuel pump harness with an upgraded intank pump, that eventuality should be minimized (I hope)?
And yes, FMU's suck wind! Run 36-50 lb/hr injectors with an ECM and programming that can handle it.
*It seems to possibly be possible to run the Sy/Ty Boost Aware 749 ECM Code on the Vette's 727 ECM, with just a minor repinning? This would allow the use of an Electronic Waste Gate Controller in a feeback loop with a 2 BAR MAP etc! Interesting idea eh?
Lots of boost related safeguards in that scenerio, I hope it'll get along with the Vette's CCM and FX3 Controller though?
Superchargers are fun- I'm making 510 ft-lbs at the rear wheels with my lowly P600b... Good luck with your project :cool:
*Yes, I've decided to run and Intercooled or Water/Alcohol Injected 6PSI Max (limited by a Pop-Off/BOV/Wastegate Valve), figuring about a 40% gain. I think that if I keep the tune good and phat, the IAT's low, and the boost/cylinder pressure mild the cast pistons could have a fairly long life.
That being said I like your idea of using a mech BOV that can be adjusted to limit boost. It should allow you to build more low-mid while keeping it from blowing up at redline; plus you could turn it up/down depending on gasoline quality, etc. Maybe a wastegate would work but I bet the pressure range from the hot exhaust is a lot higher than the 8-15psi in your intake.
*Agreed...
Tying the pressure relief to fuel pressure sounds like a good safety measure; that's how I destroyed my first SC engine- the damn fuse blew on the ATI fuel pump and it went really lean with WFO throttle on the front straight.
Exactly the failure I'm trying to avoid, though if I dump the FMU and use the factory fuel pump harness with an upgraded intank pump, that eventuality should be minimized (I hope)?
And yes, FMU's suck wind! Run 36-50 lb/hr injectors with an ECM and programming that can handle it.
*It seems to possibly be possible to run the Sy/Ty Boost Aware 749 ECM Code on the Vette's 727 ECM, with just a minor repinning? This would allow the use of an Electronic Waste Gate Controller in a feeback loop with a 2 BAR MAP etc! Interesting idea eh?
Lots of boost related safeguards in that scenerio, I hope it'll get along with the Vette's CCM and FX3 Controller though?
Superchargers are fun- I'm making 510 ft-lbs at the rear wheels with my lowly P600b... Good luck with your project :cool:
Thank you for all your help!
Doug
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Joined: May 2002
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Re: D1 Procharged L98 Design Excersise... (krivera)
Update...
It seems that the D1 is not legal here in CA, so I'm going to have to use one of the following...
P600B/P-1SC or P-1SC-1.
Has anyone experienced the difference between the P-1SC and P-1SC-1?
I think I'd prefer a SC if I can get it in with the FX3 via a modified bracket and reclocking. I don't mind changing the oil every once in a while to avoid the possibility of bloewr debris in the engine's oil etc.
Thanks...
Doug
It seems that the D1 is not legal here in CA, so I'm going to have to use one of the following...
P600B/P-1SC or P-1SC-1.
Has anyone experienced the difference between the P-1SC and P-1SC-1?
I think I'd prefer a SC if I can get it in with the FX3 via a modified bracket and reclocking. I don't mind changing the oil every once in a while to avoid the possibility of bloewr debris in the engine's oil etc.
Thanks...
Doug
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From: Houston Texas
Re: D1 Procharged L98 Design Excersise... (doug_dayson)
Hi Doug, one thing occured to me if you use a BOV rated at 7 psi and your compressor is pushing 10, then when under load and pushing over 7 psi your BOV will be going off. Most BOV's make a funny noise and if your running down the road with compressor pushing over 10 then you are going to have a funny sounding car. Turbos with BOV's only make that sound for a split second as turbos surges against a closed tb. Waste gates usually have their own muffler or they dump back into exhaust. Am I making sense?
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Re: D1 Procharged L98 Design Excersise... (BAM92)
Thanks Bryan, I had considered that, and was thinking of plumbing it post Intercooler, and pluming the Wastegate's output back to the Air Cleaner. My only experience with Wastegates was listening to them on the KART Cars at Laguna Seca this year.
I've now learned that I can't use a D1 due to smog requirements, so I'll be using a P600B/P-1/P-1SC etc, so 10PSI with the stock pulleys is a pipe dream anyway, so I'll just pulley it for 6PSI at redline post IC, and set the Wastegate for 7PSI (so it'll act as a failsafe to protect from over-revving etc). I'll add to that a fuel pressure referenced Pop-Off Valve, so it'll perhaps look like this...
a) A post IC 6PSI Pulley'd P600B/P-1/P-1SC-? (should have no problems with the 6 rib belt and pulleys at this boost level).
b) A standard BOV - Anti-Surge Valve opening with vacuum, plumbed back to tha Air Cleaner for minimum noise.
c) A Wastegate set at 7PSI. This will not pop unless something unexpected happens, so noise will not be an issue, but rather a warning sign.
d) An Electronically Controlled Solenoid Valve referenced to Boost and Fuel Pressure, in that if FP falls below a threshold while under boost the valve pops, there by venting boost and saving the motor. I'll plan on installing an upgraded intank Fuel Pump with the factory harness, and reprogram the 727 ECM to use larger Injectors, and do the timing retard etc.
In this scenerio the Fuel Pressure switch will pop the vent if fuel pressure sags under boost, there by saving the motor in times of trouble.
What do you think?
Doug
I've now learned that I can't use a D1 due to smog requirements, so I'll be using a P600B/P-1/P-1SC etc, so 10PSI with the stock pulleys is a pipe dream anyway, so I'll just pulley it for 6PSI at redline post IC, and set the Wastegate for 7PSI (so it'll act as a failsafe to protect from over-revving etc). I'll add to that a fuel pressure referenced Pop-Off Valve, so it'll perhaps look like this...
a) A post IC 6PSI Pulley'd P600B/P-1/P-1SC-? (should have no problems with the 6 rib belt and pulleys at this boost level).
b) A standard BOV - Anti-Surge Valve opening with vacuum, plumbed back to tha Air Cleaner for minimum noise.
c) A Wastegate set at 7PSI. This will not pop unless something unexpected happens, so noise will not be an issue, but rather a warning sign.
d) An Electronically Controlled Solenoid Valve referenced to Boost and Fuel Pressure, in that if FP falls below a threshold while under boost the valve pops, there by venting boost and saving the motor. I'll plan on installing an upgraded intank Fuel Pump with the factory harness, and reprogram the 727 ECM to use larger Injectors, and do the timing retard etc.
In this scenerio the Fuel Pressure switch will pop the vent if fuel pressure sags under boost, there by saving the motor in times of trouble.
What do you think?
Doug
Hi Doug, one thing occured to me if you use a BOV rated at 7 psi and your compressor is pushing 10, then when under load and pushing over 7 psi your BOV will be going off. Most BOV's make a funny noise and if your running down the road with compressor pushing over 10 then you are going to have a funny sounding car. Turbos with BOV's only make that sound for a split second as turbos surges against a closed tb. Waste gates usually have their own muffler or they dump back into exhaust. Am I making sense?
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From: Houston Texas
Re: D1 Procharged L98 Design Excersise... (doug_dayson)
Black Bart as I said in my email is the one for this as his knowledge of forced induction vehicles ( includes motorcycles) is far superior to mine. He is very good at fabrication too. My understanding is the ati kits ic's loose boost pressure meaning that you might have 10 psi going in but you will only have 6 on the other side. These guys on this forum can better answer that. Black Bart custom made his. You will probably need a MSD 6AL with BTM as a safety measure and for better spark. Racetronix makes a incredible kit for out cars to increase fuel capacity. What about a cam swap to lower boost pressure since boost in relative to back pressure? Just a thought.
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Re: D1 Procharged L98 Design Excersise... (BAM92)
I've talked in depth with Black Bart as well, and I thank him again for his time, as well as everyone else who's helped out. I agree, his knowledge in this arena is second to none!
I believe that at the mild boost level that I'm talking about, that the ATI IC's lose about 2-2.5PSI, so while not being ideal, they'll work at my power level (425-450HP at the crank).
I believe the 91 C4's get the twin IC set-up?
I'm planning on using some traditional bolt-ons as well, but only those that won't lose my low end (91 TPI, as I'm counting on the blower to create the top end). To that end I'm looking at Big Long Tube Runners, and a Big Base Manifold, 1.6 Rockers, and a Random Tech CAT with gutted Pre Cats. Optionally, I can pocket port the heads as well, and/or a cam etc. I'll be expecting between 300HP (stock heads), and 325HP (pocket ported heads with opened chambers to 64cc) naturally aspirated, and an additional 40% from the 6PSI IC'd Blower, for 420HP-450HP at the crank.
I'd consider using the Wastegate to limit boost to 6PSI if I can get 8PSI out of the blower without belt slip, but from what I've read that's not easy, and I'm not budgeting all new pulleys at this stage anyway.
Someday I'll likely move outof CA, and then build a forged bottom end etc, so I'll be wanting a P-1 or P-1SC so it can be upgraded to a D1 when legality stops being an issue.
I won't be tuning for max power with the stock bottom end anyway, so I'm thinking of skipping the MSD BTM, and just reprogramming the PE Fuel and Timing Tables, and using larger Injectors and a upgraded Intank Pump (along with colder plugs). This allows factory control of timing vs IAT's, and uses the OEM Fuel Pump harness and Relay for reliability's sake (quieter too).
Since the goal here is not max power, but rather a reliable 425-450HP plus/minus with the stock bottom end, hence the mild boost and failsafe measures. If detonation is eliminated, and boost kept at 6PSI (sealevel), there's hopefully no reason why a stock bottom end can't enjoy a long life with a street duty cycle, or at least I hope so?
Have I forgotten anything?
Thanks...!!!
Doug
I believe that at the mild boost level that I'm talking about, that the ATI IC's lose about 2-2.5PSI, so while not being ideal, they'll work at my power level (425-450HP at the crank).
I believe the 91 C4's get the twin IC set-up?
I'm planning on using some traditional bolt-ons as well, but only those that won't lose my low end (91 TPI, as I'm counting on the blower to create the top end). To that end I'm looking at Big Long Tube Runners, and a Big Base Manifold, 1.6 Rockers, and a Random Tech CAT with gutted Pre Cats. Optionally, I can pocket port the heads as well, and/or a cam etc. I'll be expecting between 300HP (stock heads), and 325HP (pocket ported heads with opened chambers to 64cc) naturally aspirated, and an additional 40% from the 6PSI IC'd Blower, for 420HP-450HP at the crank.
I'd consider using the Wastegate to limit boost to 6PSI if I can get 8PSI out of the blower without belt slip, but from what I've read that's not easy, and I'm not budgeting all new pulleys at this stage anyway.
Someday I'll likely move outof CA, and then build a forged bottom end etc, so I'll be wanting a P-1 or P-1SC so it can be upgraded to a D1 when legality stops being an issue.
I won't be tuning for max power with the stock bottom end anyway, so I'm thinking of skipping the MSD BTM, and just reprogramming the PE Fuel and Timing Tables, and using larger Injectors and a upgraded Intank Pump (along with colder plugs). This allows factory control of timing vs IAT's, and uses the OEM Fuel Pump harness and Relay for reliability's sake (quieter too).
Since the goal here is not max power, but rather a reliable 425-450HP plus/minus with the stock bottom end, hence the mild boost and failsafe measures. If detonation is eliminated, and boost kept at 6PSI (sealevel), there's hopefully no reason why a stock bottom end can't enjoy a long life with a street duty cycle, or at least I hope so?
Have I forgotten anything?
Thanks...!!!
Doug
Black Bart as I said in my email is the one for this as his knowledge of forced induction vehicles ( includes motorcycles) is far superior to mine. He is very good at fabrication too. My understanding is the ati kits ic's loose boost pressure meaning that you might have 10 psi going in but you will only have 6 on the other side. These guys on this forum can better answer that. Black Bart custom made his. You will probably need a MSD 6AL with BTM as a safety measure and for better spark. Racetronix makes a incredible kit for out cars to increase fuel capacity. What about a cam swap to lower boost pressure since boost in relative to back pressure? Just a thought.
