Supra Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
2,029 Posts
Discussion Starter #1
Need help, im currently BPU and going to be putting in my AEM EMS and going to buy HKS 272s within the next week... I was wondering is it manditory to upgrade the springs and retainers or is it ok to keep the stock valvetrain??? Im sure replacing the springs and retainers is a good idea....

Lets hear it guys

Geno~
 

·
No Ego or Arrogance!!!!!!
Joined
·
744 Posts
From my point of view,I would,but Matt Miller when racing his stock long block with 264's with a 74mm at 32psi g-force and rev to 8000rpm,for two years.I guess you decided.If you upgrade your springs do valvestem too.
 

·
Registered
Joined
·
9,698 Posts
IMO whats another $300 when putting in cams, etc. When I do my valve stem seals I am going to do cams and springs/retainers...it just makes too much sense.

Jason
 

·
Registered
Joined
·
2,029 Posts
Discussion Starter #5
Your valve stem seals are brand new. You should change the springs and retainers with the 272s going in though.
the seals are new? hmmm tell me more about my car haha. yeah i figured i mine as well change the springs and retainer while im at it.

brian i sent you a pm too...

geno~
 

·
T88 YOU
Joined
·
3,567 Posts
if you have the money and the time to install them, why not? but they are not a necessity, the car will run without them. the only way it would benefit you is if you were trying to rev to 8000rpm and up.
 

·
Registered
Joined
·
2,029 Posts
Discussion Starter #7
if you have the money and the time to install them, why not? but they are not a necessity, the car will run without them. the only way it would benefit you is if you were trying to rev to 8000rpm and up.
got ya... yeah im going to just do it while im at it. Question for you or anyone else here: does anyone know what i can bump my rev limit up to @ BPU and HKS 272s, AEM, valve springs/retainers???

Thanks guys!
Geno~
 

·
Old School
Joined
·
4,067 Posts
^ Get your car on a dyno and find out. My guess is the tiny turbine side on the stock twins will be a major restriction, they'll be all out of flow long before those big cams make themselves felt.

If your longterm plans are a 71+ mm single, the 272s will work out fine. Smaller than that I think you'll find the 272s shift the power band too much to the right.
 

·
Registered
Joined
·
2,029 Posts
Discussion Starter #9
^ Get your car on a dyno and find out. My guess is the tiny turbine side on the stock twins will be a major restriction, they'll be all out of flow long before those big cams make themselves felt.

If your longterm plans are a 71+ mm single, the 272s will work out fine. Smaller than that I think you'll find the 272s shift the power band too much to the right.
got ya, yeah ill throw it up and see i guess... we'll the plan was to go w/ a SP74-gts dbb kit, AEM and full fuel system. However a few people talked me into running the stock twins into the ground for the summer and go single next spring since i only had bought the car 6 months ago. Next year ill go all out and im thinking of still starting out w/the SP74 so... im just not getting what you said b4 about shifting the power band to the right, meaning they will kick in later?? i should still make decent power with the 272s @ BPU right? i might be misunderstanding but it sounds like your saying the power is going to kick to late for stock singles?
 

·
Old School
Joined
·
4,067 Posts
Using the stock twins, my guess is 272s will make less power below 6000~6500 than either stock cams or 264s.

Stock twins (and small singles) just don't move enough air mass through the engine to take advantage of the longer duration and increased rpm limit of the bigger cams.
 

·
Registered
Joined
·
2,029 Posts
Discussion Starter #11
Using the stock twins, my guess is 272s will make less power below 6000~6500 than either stock cams or 264s.

Stock twins (and small singles) just don't move enough air mass through the engine to take advantage of the longer duration and increased rpm limit of the bigger cams.
ooo i got you, good point... food for thought i guess. ill keep it in mind. thanks man
 

·
Old School
Joined
·
4,067 Posts
Please post up your dyno numbers once you get them. I'd like to see what the graph looks like, as I'm sure others would.

Good luck!
 

·
Registered
Joined
·
63 Posts
dont bother changing the springs unless your going with a big turbo and u want to increase your useable rpm to take advantage of the power curve with 272's and a big turbo, i ran my car with 272's and an sp74 for about 60000mi with no problems, redlining at 8000 rpm all day long , the main advantage of dual springs is to decrease return time of the valve, so u can increase redline and decrease chance of valve float, but if i had stock twins i would go with 264's, i previously had that setup on another supra with great success, even an sp74 with 264's is fuc...in awesome for the street. i am now running a sp76 with 272's a fully ported and polished head and dual valve springs and i am redlining at 9500rpm, i believe i can raise it up more maybe to 10000, but once u get over the stock 8000rpm limit u take on a great huge task, when toyota balances their parts they have a tolerance of like three grams, at 8000rpm this will not be much of a problem however at 9500rpm it becomes a huge problem, i already cracked one of my crank's at this rpm because of this, i just put my car back together and we balanced all the parts with a tolerance of half a gram, it worked out beautiful, i also installed a unortodox crank damper, but we are doing this ourselves, if you dont have the equipment and a shop is doing the work it can be very expensive just for an extra 1500 rpm, my advice is talk to larry at sound performance, i know him personally and he has more hands on experience with supras than anyone. off the top of his head he can tell you for sure.
 
1 - 13 of 13 Posts
Top