hayabusa oem head bolt specs with stage 1 turbo

markwt

Registered
I have a Gen1 Busa and will be running about 8 psi. For now I am just using the factory head bolts which from what I have read seems pretty safe, beyond on that I need to switch to studs. Two part question, what do you all feel is the psi range that I need to go to studs, I still have motor town down so I can switch if need be. If I can use factory bolts safely, should I use the OEM torque spec or is there a safety factor that I should make head bolts slightly tighter due to turbo boost. Since such critical information, I wanted to ask the experts. Thanks for the help.
 
Anytime a motor comes out for even just a spacer, I highly advise to spend the extra money to go with the promod studs. 8 psi is fine on stock studs, and I've seen as much as 10 on stock motors.

However IF for some reason you get an overboost situation, chances are you'll stretch the head bolts. At that point you'll need to for sure upgrade. Figure this. 2 head gaskets will run you about $160, plus oil, coolant, and time it takes to pull the engine to fix the problem.

Or you can spend $160 now on promod studs and won't have to worry about it later. Other notes worth mentioning, are if you got a spacer, good head gasket installed, and cam sprockets installed you can run over 300hp on the stock bottom end if you have the fuel system to support it. Can't do that with stock head bolts. And lastly it's a LOT easier to get the cylinders back on with studs.
 
Sound advise!
As the old saying goes, "If you don't have the money or time to do it right the first time, where will you get it to do it over".
 
Disclaimer, Yes I know this thread is old, but great advice! I was just on another forum where a post asked and showed a picture of a 5 year old drive belt that was damaged. He was asking if he should replace it, and over 65% said just run it. Sometimes I am just amazed! Good sound advice is hard to come by these days!
 
Disclaimer, Yes I know this thread is old, but great advice! I was just on another forum where a post asked and showed a picture of a 5 year old drive belt that was damaged. He was asking if he should replace it, and over 65% said just run it. Sometimes I am just amazed! Good sound advice is hard to come by these days!
Hi. I am more of 1/2 ARP studs and crank studs ARP case bolts and an APE stud at the output shaft.
 
You don’t need billet to make that kind of power. Just a good builder. This has been done before.
Hi. They would be a lot stronger. I have cases that Rick Stetson did for me. Eric at DAS is helping me with the tune and some custom machine work and welding on the frame as I am moving the swingarm pivot up 12mm. On my $3824.00 intercooler intake to better fit the ID injectors. 1050 on the bottom and 2600 on top.
 
Hi, I’m intend to install ARP main studs on the bottom end. Is distortion of the bearing seats a common thing? if so where would I get the case align honed?
thanks in advance !
Two sets of gen 1 cases I have were Done by Rick Stetson at HMP
I do not believe he is still taking in work any more so Not sure who else can hook you up

any REALLY good machine shop should be able to do it
 
Two sets of gen 1 cases I have were Done by Rick Stetson at HMP
I do not believe he is still taking in work any more so Not sure who else can hook you up

any REALLY good machine shop should be able to do it

Besides line boring, it can almost all be done in your garage so why does everyone insist on keeping this info secret lol especially if the main guy isn’t taking in work anyway.
 
Two sets of gen 1 cases I have were Done by Rick Stetson at HMP
I do not believe he is still taking in work any more so Not sure who else can hook you up

any REALLY good machine shop should be able to do it
Thanks for the lead on this I’ll try to get ahold of Rick.
 
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