How much boost for the street?

R

robertf

Active Member
Joined
Mar 21, 2014
So Im installing TA Perf. downpipe and Precision Ext wastegate. My current boost is regulated at 20 psi for now.
I have a few mods including: Champ CNC irons/Champ portmantched intake/70mm TB/Tony Dequick SLIC/Razor Alky/Erics 93 alky chip/60lbs injectors/ATR 2.5 exhaust/TR6 ign. Block is otherwise unopened.
2 options are 22.8 lbs boost and 24.4 lbs boost. I dont track it but I'd love to see 24 lbs safely if possible just
for the fun factor. Am I crazy for wanting 24lbs or should I be safe and go 22.8lbs?

Thanks very much.
 
robertf said:
So Im installing TA Perf. downpipe and Precision Ext wastegate. My current boost is regulated at 20 psi for now.
I have a few mods including: Champ CNC irons/Champ portmantched intake/70mm TB/Tony Dequick SLIC/Razor Alky/Erics 93 alky chip/60lbs injectors/ATR 2.5 exhaust/TR6 ign. Block is otherwise unopened.
2 options are 22.8 lbs boost and 24.4 lbs boost. I dont track it but I'd love to see 24 lbs safely if possible just
for the fun factor. Am I crazy for wanting 24lbs or should I be safe and go 22.8lbs?

Thanks very much.
Click to expand...


why are you limited to those 2 numbers ... let the car tell you what you can run
 
Well, by using different colored springs in the wastegate I can get different boost levels. I could install a boost controller but I figured I'd install the spring combo that limits it to either 22 or 24 lbs and leave it alone.
BTW I'm running 93 octane. Erics chip is set for 23/25 psi but the OEM solenoid limits it to 20 PSI. Car pulls very hard at 20 psi.
 
robertf said:
Well, by using different colored springs in the wastegate I can get different boost levels. I could install a boost controller but I figured I'd install the spring combo that limits it to either 22 or 24 lbs and leave it alone.
BTW I'm running 93 octane. Erics chip is set for 23/25 psi but the OEM solenoid limits it to 20 PSI. Car pulls very hard at 20 psi.
Click to expand...


those are just numbers ... let the car tell you what it likes
 
Any amount of boost can blow your motor up.....or not.

You need to know if your your combo can support what you are are throwing at it. If your looking for a guideline based on your combo and what others are doing, you may get answers anywhere from 17 to 27.......or more. That's a big area.

I know how you feel because I too am always looking for easy cut and dry answers. But unfortunately in this case that wont work.

Based on your short list of mods, 24 lbs should be safe. But not without filling in all the blanks with the assumption that everything else is correct,
 
on just 93 oct. start at 10 psi and watch for KR.
on my old build the most boost i could get from just 93 oct was 13 psi. at 15 the knock sensor would come alive.
Good luck and have fun.
BTW on 93 and ALKY @ 25 psi was a LOT of fun.
 
I've slowly worked up to 27psi with no knock. Not running any high timing though.
Agreed that 25+ psi is very fun on the street!
 
An important question would also be what tires are you running. It wont matter how much boost that you are trying to achieve if you're doing the gbody shuffle. And once again boost is just a number, dont be so fixated on it. 20lbs is 20lbs but can be a very different hp/tq levels on different engines. I have never changed wastegate springs ( could be my greatest fault, one car has dual Deltagates) but I do have the manual Turbonetics knob , and several brands of electronic CO2 boost controllers that can change my settings on the fly.
 
There is no reason to run 24 lbs on 93 octane that is trouble waiting to happen. Install the ALKY and run the chip for it and you are laughing 24 plus lbs of boost should be no problem. It's a cheap way to run boost on the street.
 
robertf said:
So Im installing TA Perf. downpipe and Precision Ext wastegate. My current boost is regulated at 20 psi for now.
I have a few mods including: Champ CNC irons/Champ portmantched intake/70mm TB/Tony Dequick SLIC/Razor Alky/Erics 93 alky chip/60lbs injectors/ATR 2.5 exhaust/TR6 ign. Block is otherwise unopened.
2 options are 22.8 lbs boost and 24.4 lbs boost. I dont track it but I'd love to see 24 lbs safely if possible just
for the fun factor. Am I crazy for wanting 24lbs or should I be safe and go 22.8lbs?

Thanks very much.
Click to expand...
As others have stated boost is just a number.if you want to make more boost you will hit a point where octane is needed also on a street car having the intake charge cooled down is important.saftey is in the octane and volume of fuel (cushion).you need to tune to the fuel you are using and see what your car likes
 
87GN_Bart said:
There is no reason to run 24 lbs on 93 octane that is trouble waiting to happen. Install the ALKY and run the chip for it and you are laughing 24 plus lbs of boost should be no problem. It's a cheap way to run boost on the street.
Click to expand...
I am running Alky. At 20 lbs I get zero knock. Been doing that for many years. I recently renewed the HG due to a alky pump failure, but alls good now. I just feel with my combo it could stand 24/25 psi.
 
Last edited:
robertf said:
I am running Alky. At 20 lbs I get zero knock. Been doing that for many years. I recently renewed the HG due to a alky pump failure, but alls good now. I just feel with my combo it could stand 24/25 psi.
Click to expand...
Turn it up in small increments until you see kr.
 
See what timing you are running first, Eric writes it on the chip... "x" psi of boost at 21/23 degrees timing is a lot different than "x" boost at 15/17 degrees. "Boost" isn' an indication of a certain amount of power like the people at the gas station asking questions seem to think it is. I ran 34psi on my combo but with only 16 degrees of timing, 2 alky nozzles and no knock. Reason: Cal told me to "make the power with boost" and keep the timing conservative. You need to experiment and log data. Also, use a boost controller with your external gate and a lower pressure spring, the spring only controls the minimum pressure you can run, you'e not locked into running only on spring.
 
haywire4130 said:
See what timing you are running first, Eric writes it on the chip... "x" psi of boost at 21/23 degrees timing is a lot different than "x" boost at 15/17 degrees. "Boost" isn' an indication of a certain amount of power like the people at the gas station asking questions seem to think it is. I ran 34psi on my combo but with only 16 degrees of timing, 2 alky nozzles and no knock. Reason: Cal told me to "make the power with boost" and keep the timing conservative. You need to experiment and log data. Also, use a boost controller with your external gate and a lower pressure spring, the spring only controls the minimum pressure you can run, you'e not locked into running only on spring.
Click to expand...
Chip is 25 psi at 21/23 timing. Alky pump is new. I'm going to install the 24 lb spring combo in the wastegate and see how things pan out. I got the 60lb flowmatched injectors from Eric with the chip combo. Walbro 340 in the tank.
 
I would still install a lighter spring combo and use a boost controller to sneak up on the number your car/alky setting likes. Wastegate spring rate isn't an exact science, I wouldn't slap in their "25 psi" spring set and go mash it expecting to see exactly 25psi. If you do it anyway be cautious the first time out, watch the scanmaster and get ready to lift just in case
 
haywire4130 said:
I would still install a lighter spring combo and use a boost controller to sneak up on the number your car/alky setting likes. Wastegate spring rate isn't an exact science, I wouldn't slap in their "25 psi" spring set and go mash it expecting to see exactly 25psi. If you do it anyway be cautious the first time out, watch the scanmaster and get ready to lift just in case
Click to expand...
Good advice. I'll install my Lorenz controller as well. I'll go for lighter spring combo.
 
I' not trying to tell you what to do, just suggesting caution. Factors like the size of your wastegate hole and how well it matches up with the hole in the downpipe can make bad things happen quick. If you put in a light spring, make a few "safe" pulls and see what it makes on just the spring, then start adding psi with the controller. My car makes 6psi on just the spring and the top port of the wastegate open. Not saying you need to go that low but that's what was in it and it works, the pipe was on the car when I got it.
 
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