Do I need new springs? Thinking of just swapping heads too...advice please!
04-26-2010, 12:10 PM
#1
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Do I need new springs? Thinking of just swapping heads too...advice please! Been a LONG time since I've posted on here. Bought my old 02 Z06 back from my dad. He put about 30k miles on it. Relevant mods are:
LG Pro Longtubes
224/228 114+2
Original Texas Speed CNC LS6 heads (i think 237 port volume)
Car never really made good power with those heads some said because port volume was so huge that velocity suffered. It made 420 rwhp when it made 410 rwhp cam only.
First question is how long are springs good for? I'm fairly sure they are 918 springs.
Second question, what is a good budget head to swap to that will flow well and give me good velocity to help with the midrange?
Thanks.
LG Pro Longtubes
224/228 114+2
Original Texas Speed CNC LS6 heads (i think 237 port volume)
Car never really made good power with those heads some said because port volume was so huge that velocity suffered. It made 420 rwhp when it made 410 rwhp cam only.
First question is how long are springs good for? I'm fairly sure they are 918 springs.
Second question, what is a good budget head to swap to that will flow well and give me good velocity to help with the midrange?
Thanks.
04-26-2010, 12:27 PM
#2
As far as the springs, I'd change them w/ head swap. Rule of thumb is 30K depending on ramp rate & lift. Need more info about heads to say whether or not they are reducing velocity. What are the recorded numbers from the MAF & MAP through the RPM range? What intake & TB?
04-26-2010, 12:55 PM
#3
Those heads are'nt bad with a big enough cam....and that is a pretty short duration (you should include the lift #'s as well). 30k on that small of cam is not many on 918's but I agree completely w/ LS1-450 on changing anytime the heads are off.
04-26-2010, 01:17 PM
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Lift is 581/588 - XE-R lobes IIRC
Yes, I was just thinking that I would pull the heads and resell them to someone with a big cam and just disclose that they need new springs.
LS6 intake, ported TB
Don't know MAF/MAP readings. Jeremy Formato tuned the car, so it isn't a lack of tuning that is causing the low power.
Yes, I was just thinking that I would pull the heads and resell them to someone with a big cam and just disclose that they need new springs.
LS6 intake, ported TB
Don't know MAF/MAP readings. Jeremy Formato tuned the car, so it isn't a lack of tuning that is causing the low power.
04-26-2010, 01:33 PM
#5
Wasn't thinking that the tune had anything to do w/ it. The MAF & MAP values @ given RPM's would have given a hint as to whether or not the volume of the runner in the head was an issue. Personally, 420 RWHP doesn't sound bad w/ that cam, intake & TB. What is the TB ported to? If less than 85mm, then I'd say that the TB & inlet size on the LS6 is more of an issue than is the volume of the runner. Can't say for sure without logged MAF & MAP info..
The inlet size on the LS6 intake can be increased w/ some TLC.
You may swap heads & then remain @ 420RWHP.
