How much boost on stock block?

[1fastfox]

I am currently running 8# boost with my KB and I was looking to add more boost and some methanol injection. I have a stock bottom end, AFR 165 heads, Steeda 19 Cam. Was looking at running either 10 or 12# of boost with the methanol. Just trying to get some idea of what the stock block can realistically hold? The car is a n 88 Mustang with stock 302.
Thanks,
Chris

 

[AdirondackFox08]

I'm not sure man, it would depend on how much power you're getting out of the combo... I would "think" that with the h/c/i you have and running 12 lbs of boost that you should be close to how much power the block can stand. The stock block can handle around 500 hp at the crank, some people have had it split at a lower hp level and some have had it last with more hp than that for a while. I'm sure someone else will chime in and help you out further.

 

[dsblk93gt]

Yea the KB make more TQ than HP too. There is no such thing as a safe boost level, it is more less a safe HP level. Keeping it under 500ft lbs would be a good idea.

What KB is it? I would stay around 10lbs if it was me. And with adding w/a with the KB it is really tough to get the temp drops guys with centrifugals do.

Good thread on this subjet, I could write it all but this is better
http://forums.corral.net/forums/showthread.php?t=1071052

 

[Chevy_Guy]

Torque is the enemy.

 

[Art Caley]

As noted above its not really the boost level that is the culprite. Different engine combos will show different boost pressures with the same air flow.

Having said that, its the tune and combo that is the deciding factor. With a similar combo as yours and with a Snow Performance boost cooler I dynoed up to 16 psi with my Vortech and produced 533 rwhp, 501 rwtq. The tune (done by Mustang Magic) is what kept it safe. But even with a safe tune this block won't last forever.

You should be able to run 12 psi in my opinion.

 

[dsblk93gt]

The KB is a totally different animal though, and testing has not showed a huge decrease in charge temps even using 2 nozzles and spraying before and after the supercharger. You still get the added benefit of higher octane but that's about it. Those are decent #'s but I'm guessing the timing is on the conservative side. My S-Trim made 558rwhp with h/c/i on a stock Explorer shortblock before I had it sent out to get upgraded to an Si-Trim.

 

[dsblk93gt]

Torque is the enemy.

Why do you think Honda motors last so long...

 

[92BIGREDBEAST]

How much boost could a stock block take, if a stock block could take boost! A stock block could take as much boost as a stock block could take if you put the boost to is to find out. Let us know when you smell antifeeze! LOL

 

[BlkStang89]

i was running 14psi with a junk ebay 70mm without any issues. switched to a 76mm and ran 10-11psi without a problem all year on a stock block on pump gas and was running bottom 11's. drove to and from the track on sundays and drove to work during the week with no issues

 

[92BIGREDBEAST]

i was running 14psi with a junk ebay 70mm without any issues. switched to a 76mm and ran 10-11psi without a problem all year on a stock block on pump gas and was running bottom 11's. drove to and from the track on sundays and drove to work during the week with no issues

Any pics of this set up? I see in your info a 13.3 @ 105. What did you do to get bottom 11's? Lets see the car!

 

[BAzombie]

How much boost could a stock block take, if a stock block could take boost! A stock block could take as much boost as a stock block could take if you put the boost to is to find out. Let us know when you smell antifeeze! LOL

Hey you SC's .... Stop boosting my block. new gieko commercial.



Sorry, just had to do that.

 

[The Bone]

run 1000lbs boost.....if the hp and tq numbers are low you are still ok
read the above posts they are pretty dead on

 

[dsblk93gt]

run 1000lbs boost.....if the hp and tq numbers are low you are still ok
read the above posts they are pretty dead on

 

[dsblk93gt]

i was running 14psi with a junk ebay 70mm without any issues. switched to a 76mm and ran 10-11psi without a problem all year on a stock block on pump gas and was running bottom 11's. drove to and from the track on sundays and drove to work during the week with no issues

But you do realize that turbo #'s and sc #'s are different right? You have the power it takes to spin the supercharger that doesn't get figured into the overall amount of power.

Boost is just a measure of restriction, so a motor with great flowing heads,intake, etc. is going to "see" less boost. There are guys running 17-18lbs of boost on stock 5.0 motors making around 380-400rwhp, that same pulley combo on a well breathing engine will see around 13lbs.

 

[BlkStang89]

But you do realize that turbo #'s and sc #'s are different right? You have the power it takes to spin the supercharger that doesn't get figured into the overall amount of power.

Boost is just a measure of restriction, so a motor with great flowing heads,intake, etc. is going to "see" less boost. There are guys running 17-18lbs of boost on stock 5.0 motors making around 380-400rwhp, that same pulley combo on a well breathing engine will see around 13lbs.

yeah i here ya i know they are different, bigger heads and less restriction all that i here ya was just giving him what my combo was and what i ran for something to compare to

 

[dsblk93gt]

yeah i here ya i know they are different, bigger heads and less restriction all that i here ya was just giving him what my combo was and what i ran for something to compare to

Sounds like a nice setup..whats the whole combo?

 

[BlkStang89]

Any pics of this set up? I see in your info a 13.3 @ 105. What did you do to get bottom 11's? Lets see the car!

yeah the 13.3 was a long time ago when i first joined just havnt updated it yet, Its a old pic from when i was putting it together and it looks dirty as hell but its just a simple H/C/I set-up with a cheap on3 kit and last all summer and ran low 11's and even did it with a wounded transmission.

heres a vid from my first day out with it at the track, was still sorting out problems

 

[dsblk93gt]

Cool, I have wondered how those on3 kits would work

 

[BlkStang89]

it wasnt bad, had some fitment issues with the down pipe and the wastegate that came with the kit was junk but besides that wasnt bad. just a 306 with TFS stage 1 cam, 170 trickflow heads and track heat upper and lower intake and supporting mods.

 

[cobra20sc]

But you do realize that turbo #'s and sc #'s are different right? You have the power it takes to spin the supercharger that doesn't get figured into the overall amount of power.

Boost is just a measure of restriction, so a motor with great flowing heads,intake, etc. is going to "see" less boost. There are guys running 17-18lbs of boost on stock 5.0 motors making around 380-400rwhp, that same pulley combo on a well breathing engine will see around 13lbs.

Very good point. For a typical 10psig pulley setup on an S-trim moving 49lb/min of airflow is about 50HP load not including bearing and gear losses. so 500HP at the crank is really 550HP.

Tune has ALOT to do with how long the motor will last. Bad A/F or too much timing can break the block with only 400HP