throwit

I am on the fence about about changing from Poly to Spherical, or getting my heads ported and picking up roughly 15whp...

They both cost about the same, but I don't have the money to do both right now.

So I was wondering which mod would produce a bigger difference in laptimes...anyone have any direct experience with this?

All the threads I have read about Poly to Spherical typically talk about how it feels, and dont list actual laptime improvements. As far as whp, I have always heard that adding 10whp should yield about a half sec drop in laptime.

Any input is appreciated

rustyguns

i vote bearings and get more seat time then you dont need the 15 hp

SLandstra_Z06

I vote for the spherical bearings. I put the Pfadt sphericals in this year and it transfromed my car on the track. I don't have a before-and-after comparison, but I can tell you the handling is improved and I was able to reduce the amount of camber. The car is hooked up!!!!

AU N EGL

Agreed.

HP is sexy as hell, but seat time makes you faster

Pontiaker

Interesting....

Hey buddy!

throwit

Would it make a difference if the heads were being Mamofied?

Seems strange that no one, so far, thinks 15 more whp equates to lower laptimes than spherical bearings...especially considering I already run poly.

Thanks again.

rustyguns

maybe because we know. poly still flexes and it binds and wears out. we see guys with 100 hp more than us and they can't keep up.

seat time and suspension and really, really good tires will always kick *** on a little HP

throwit

cool, thanks bud

tjZ06

Sorry to thread hijack a bit, but what did you change your alignment to/from when switching to the bearings? I just put them in my C5Z.

-TJ

John Shiels

10 hp will not get you a half a second IMHO. I would say tenth of a second on 1:30 track.

stevensa

Neither, send whatever you were planning on spending to me and I will give it a good home! This way you don't have to make these tough decisions.

gkmccready

Plenty of spherical solutions out there now, too: LGM, DRM, Pfadt, Black Dog. Curious if anybody has looked at multiple brands?

Bink

What Engine?? What mods to the engine? Cam with the port work??

geerookie

312hp to the wheels and pass guys in 600hp Corvettes (not on the straights).
Sphericals will transform the handling of your car. Poly's bind really bad!
When I installed them I was blown away at the difference. You have to experience it, to believe it. Most significant difference is when you turn the steering wheel....your car turns. Also things seem smoother because the tires stay on the track.

L98Terror

I say 15 HP if you are racing, you pass on the straights and breaking zones rarely mid corner.

I changed from delrin bushings because all the "suspension experts" were telling me I'm binding, I'm binding that's why the car isn't dropping, there's bind. Well I switched to spherical and the car still sits at the same height go figure there is no difference.

To be honest I haven't driven the car like I did last year so I don't really have great comparisons but I still have had it out a few times with the change and I didn't notice any great transformation. I also don't notice 15 HP either unless you are side by side down the back straight trying to get to that corner first.

Will you get a little different feel? sure. Will it make you faster? That depends on your driving ability and how you adjust to the car. IMO HP will make you faster no matter what, it doesn't take any skill to push that right foot down and to extract it from suspension upgrades that's where seat time and skill come into play, I've out cornered may tricked out cars with a plain old stock suspenstion, rubber bushings and all.

What do your class rules say about it? If you are only running HPDE go with the HP you can't pass in the corners anyways.

Also make sure you grease those poly bushings

John Shiels

I never understood all this binding on poly, To show a hammer or what ever small weight on an A-arm to bring it down is nothing compared to the forces a car on track creates. Keeping alignment better than poly yes.` Keeping better contact patch yes.

John Shiels

good point to look at the whole package.

SLandstra_Z06

I run Hoosier A6 or R6 tires. Before the sphericals I had the car set up with about 3 degrees of negative camber in the front and 1.5 degrees in the rear. I couldn't believe it, but I was actually wearing out the inside edge of the front tires with this alignment.

I now run 2.5 degrees of negative camber in front and no change (1.5 degrees) in the rear. Tire wear and grip are great with these camber settings. Different tires like different amounts of camber, but for Hoosiers, this is the ticket with the Pfadt sphericals. I also have camber lock-outs, GM T-1 fiberglass springs and sway bars with adjustable end links, Penske double adjustable remote reservoir shocks.

Good luck...

Steve

AU N EGL

What tracks are you running on?


When you tell us what tracks you run, we can find times for stock Corvettes. Might be surprised how fast stock / suspension modifications can be driven.

Just ask our NASA PTA boys in here

drivinhard

Pfadt's poly kit (which is as far as we can go in TT/PT) was worth enough feel and lap time, I'd be really tempted to see what the bearings could do beyond that. You could set up your dynamic camber to max out your speed/corner grip, and if it allows you to stand the tire up a little more than before, you should gain a bit in braking and corner exit bite.

"15 RWHP" is too vague of a term to predict any lap time gain. Where in the rev band is it making it? If you are just shifting the torque curve east on the graph and not really MAKING more torque, it's not going to show up as much more speed. If you are taking the existing torque curve and moving the WHOLE thing north 10 or 15 ft/lbs, then it's going to show up a bunch more.