Just purchased the large (9# Aftercooled) Vortech blower for my car a couple weeks ago, it still hasn't even arrived yet and I now may have a small problem here. It looks like there is a really good chance that I have a lifter colapsing and starting to go south since my cam install (MTI B1.) I am 95% certain they are going to need to be swapped real soon, and definately before I do anything with the Vortech.

Well... If the heads are comming off the stockers are not likely to go back on.

I started researching good "blower" heads and have a couple of questions. Keep in mind that this is my Daily Driver, I am not trying to obtain 1000hp here, just a strong 470-500 or so to keep me happy in my daily commute. I want to keep things as simple and reliable as possible.

Everyone seems to recommend 6.0L heads to drop the compression to 9.1 or so for the blower so I can run more boost without detonation. But what if I don't really plan on increasing the boost? How would the car run? Wouldn't I loose a bunch of low end grunt because of the lowered compression? Could this turn into a computer tuning nightmare? I would assume the Vortech tunning would absolutely useless at this point right?

What about Patriot's LS6 Style Stage III heads with 68cc chambers? This should lower to about 9.8 so it's not as dramatic of a compression loss as the 72cc 6.0L's, but still about a .5 drop. Wouldn't this still allow me to keep some power from the motor and keep the low end torque and grunt? Wouldn't this be a little easier to handle tunning for as it is not much different from normal stock tables?

Questions... Questions.... Questions.
What are your thoughts?

 

I have 73cc chambers on my 6.0 heads. That is what I would recomend (72cc) I didn't notice a loss of lowend. even with these heads N/A the car would run good just a little down due to the lower compression but some of that can be compensated for with tunning.

 

How much custom tunning was involved for you? Did you have someone tune it for you, or was it through trial and error and one of those things that you always have to tinker with? Here in San Diego, we don't have many options in that department . Are you running the stock pulley or something smaller for more boost? Last question... What are the specs on your heads and who did the work?

Thanks Inspector!

 

Had Jayson at MTI tune it. Took him a little while to get it right on etc... I am running a 2.65" pulley although I would recomend the 2.75" pulley for your application as that would retain your waranty on the super charger Vortech sells this pulley but you can buy it cheaper at ASP. I used the smaller pulley to get my boost back up I see around 7# at WOT. They are TEA 2.5 6.0L heads. With a stock 480ish with ZO6 cam 500+ I would think you should still get real good numbers either way and be able to pass your emissions etc.

 

I would go with the bigger CC.....

Lower the comp the better in my opinion, I would of gone 8:1 if I had to do it over again.....you can use them for a future motor setup as well

 

I would not go that low (8:1) for the street the low compresion would let you put a lot of boost on it for big numbers etc... But it would also be a dog unless you are under boost so drivability would suffer. I also think he is concerned with emissions in CA. he can't get to radical and stay leagal and it is a daily driver. What I told you is tried and proven hear on a few vehicles in Houston with the HP ranges I gave you. It really depends on what you are tring to do I am talking about a street cars not race cars. Besides if he wanted to drop the compresion ratio he should do most of it with the pistons and not with the heads. I think he is taking about stock bottom end to. Blackhawk- at 9:1 you will not loose any lowend. Good luck PM me if you need any info on my Vortech set up. BigBos is right though if you plan on making a race car or putting a lot of boost lower would be better, but will require a forged bottom end etc.

 

A 72cc chamber would drop your compression more, not a bad thing.

Inspector12, when you had an 8:1 car what was it and how did it drive?

I am 8:1 and make like 700rwhp at 5500 rpms, you think my car might be laggy at 4500 where my converter flashes?

I'm sure an 8:1 4 cylinder is quite laggy.

 

72cc . .

 

It was a customer car that I worked on a long time ago (probabably 8-9 yrs ago.) and I hate to admit working on it but it was a Mustang 302. I can't say that it was a 100% dog because of the high stall, but it felt like a two stroke motorcycle. didn't really want to go until you really layed in it. I know a large part of that was the stall, but he's a 6 speed and he will need that low end to get out of the hole. I wouldn't think that at 4500 rpm any thing would feel "laggy"? How many # of boost are you at when you converter flashes 10-12+? I have a real hard time launching my car cause when you bring the revs up until you dump the clutch it's not under a load (No boost) so it fall on its face and then it comes alive. Still trying to work on a different method of launch the best for me is to just nail it and dump the clutch almost at the same time, but I am stil having traction issues. I am thinking of making a roll control that I can bring it up under a load and then release at the same time. I would think that any four cyclinder at 8:1 would be very slugish until it recieves a good amount of boost. LOL! My Four cylinder ls1 still ran pretty good with all its problems it just kept on puking all over my engine and then it would look like I just pulled some James Bond move and turned on the smoke screen .LOL!

 

I would go with the lower compression (and did 8.2:1) . Despite popular opinion around here you can end up making more horsepower than someone with higher static compression on pump gas due to the limits of detonation.

 

That is a proven theory a lower compersion motor with more boost makes more power than one with high compression and low boost. I just gave the guy my opinion on his stock bottom end car. I don't think he has plans for a forged bottom end as of yet. At least that is what I gathered from his questions and HP range that he gave in his original thread and the fact that he mentioned CA. emission etc...Blackhawk - by the way I forgot about your B1 cam that is a good cam for FI. MTI just recently put a heads cam (B1) car a 01 T/A that did 575rwhp with only 17 degrees of timming with about 7-8lbs of boost. That was a very safe tune for the bottom end on that car etc...

 

Wow... Holly Replies! Sorry it took so long for me check the board with the Christmas holiday and so forth...

Thanks Inspector!
Though I really never did mention trying to stay smog compliant, it really is a concern for me, just forgot to mention it. It looks like you really understand what I looking for. That car you saw at MTI is about what I would be shooting for, something fairly easy and conservative on my 70k+ mile stock bottom end. That MTI car is still putting down about 50hp more than I would have even hoped for so that's great.

I am not trying to be the absolute fastest car around, my car is a daily driver and the way it's set up it is way too heavy to be a serious race car... But I do like having some real power under there, the average 370-400hp range has just gotten real boring for me .

It looks like I will be shooting for the lower compression 6.0l's then. I was trying to initially avoid diving into smaller pulleys and custom tunning, but I also want to do it right the first time... That's the most important issue here. If lowering the compression puts down those types of numbers while still putting only 7#'s of strain on my middle-aged stock bottom... Great!

I was really worried that dropping CR this far would really kill my off the line stop-light torque, and might bring back my clutch chatter blues . But hopefully from the looks of things I should be okay.

Thanks all!

 

I wouldn't be worried about the off the line torque you will love what the extra power does for you in every way. I was just guessing from what you said in your original post about "Daily Driver" and "Simple and reliable" that usually means no issues with getting an inspection sticker and that you weren't shooting for 1000+hp like the rest of us LOL! No I really wanted 600rwhp and I could get there with a few other things I have a smaller pulley and I have a conservitive tune also. I just want to put a few miles on her before I do any more. Good luck! Have fun.