Raising the Compression with ported polished heads?!

[Venture_motorsports_LS]

Well im going on patrol for 3 months (Coast Guard)so i wanna have some engine work done while im gone! Im goin to get the head ported and polished, and thought about getting the compression raised a little too, SHOULD I. Im runnin 10.5-1 right now (STOCK), and i know the 2003-present are running 10.75-1. with the super small displacement i was think about possibly 11-1 or even 11.5-1 if i could still run 91 pump gas...any suggestions?!
Justin
VMS :eek2:

 

[CaptainZilog]

11.5 is pretty high. The sucky thing about raising compression is that if you go too far that you detonate on pump gas, you've got no choice but to layer head gaskets or back down your timing. I'd talk to engine builders who do a lot of milling work and see what they recommend, most people on this site don't mill heads and aren't as qualified as a guy with his own mill and shop. Good luck with your decision.

 

[lsbit]

I personally wouldn't take the chance. You could wait until our version of the EEC is tunable. At least then, you could back the timing off if you have a problem.

 

[Quik LS]

I posted this in another thread - but now the new SCT Flasher is working with the LS and we have been able to load new tunes into my car.

So projects like these are now possible.

 

[VTOgre]

The SCT Flasher is working now ??!!!!! When did this become working? Have you tried it yet? How well has it worked?

 

[Quik LS]

The SCT Flasher is working now ??!!!!! When did this become working? Have you tried it yet? How well has it worked?

Yep - fresh off the press - I have been working with a SCT dealer for the past month and we have been able to reflash my PCM with new tunes.

Torrie at FordPartsNetwork http://www.fordpartsnetwork.com/sct1-X.html

Just last Tuesday I got the uploads working consistantly - there was an issue with the ABS/TC and FEM, REM modules sharing the same data bus as the PCM - so when you tried to upload the other modules got in the way.

I pulled the fuses for these modules and the upload works fine.

$375 for the unit.

Your PCM code has to already be part of the SCT database for them to be able to tune it. my 01 V8 uses a TPHO and they had cracked it.

Torrie did three tunes for me - mild, wild and mbt

I did three runs each with my G-tech Pro Comp.
- mild was hardly noticable = +6.1rwhp +8.2lbs/ft
- wild better (and what I'm currently running) = +13.2rwhp +16.7lbs/ft
- MBT is a little more agressive = +21.11rwhp +20.7lbs/ft - but it does 'ping' under heavy acceleration and high rmps.

All these numbers are G-Tech numbers - not real dyno numbers. In the past my G-Tech is pretty close to my time slips at the track.

So it looks like this is the real deal - and we can finally get some tuning done!!!!!

Great news for future products - like the SuperCharger.....

 

[MAT88GT]

The sucky thing about raising compression is that if you go too far that you detonate on pump gas, you've got no choice but to layer head gaskets or back down your timing.

thicker head gaskets decrease the effect of quench in the cylinders and will cause a poorly running, detonation prone, engine to actually worsen...keep in mind that valve timing and dynamic compression have greater effects on detonation than static compression

The amount of power to be had by rasing the compression another full point isn't worth the tuning hassle...even with Johnson's new sct capabilities

Improving airflow qualities will yeild better gains than having the heads milled. BTW the 10.5:1 is subject to build tolerances which can vary greatly. W/O knowing how far your pistons are in or out of the hole, compression is a rough estimate. So, its possible that your stock, untouched engine could be 10.25-10.75:1 as is

remember that the entire combination has to be well matched...you need to address the entire flowpath to accomidate for more effecient heads

btw chambers are the only things that are polished, not ports

 

[lsbit]

Yep - fresh off the press - I have been working with a SCT dealer for the past month and we have been able to reflash my PCM with new tunes.

Do you have access to the actual software with all the tables and functions, or do they just give you basic tunes? I would be interested in looking at shift retard and different trans functions. If they really have the code nailed down, that would be great. It should attract some real performance mods.

 

[Quik LS]

Do you have access to the actual software with all the tables and functions, or do they just give you basic tunes? I would be interested in looking at shift retard and different trans functions. If they really have the code nailed down, that would be great. It should attract some real performance mods.

it comes with a 'quicktune' software that allows some limited ability for you to make changes - the software should be available shortly (in a week).

The tuners can change shift points, ...etc. You can also purchase the Pro Racer package the gives you the same software the dealer has -> http://www.modulardepot.com/product_info.php?products_id=88 only it's limited to a single car.

 

[GoldCoastLs]

sct flasher

does that flasher work for the v-6 engine as well, and what kind of gains are to be expected.

 

[Quik LS]

does that flasher work for the v-6 engine as well, and what kind of gains are to be expected.

It's PCM code based - so if they have your code, the guy can create a 'tune' for you and you can upload it.

SCT claims +14rwhp on a stock V8

My numbers are posted above.

 

[Quik LS]

if you purchase a SCT Flasher you need to pull two fuses from the passenger footwell fusebox when uploading.