099blancoss

didnt take much to show your true colors.
No I don't provide tech input to Erik, he is the instructor remember.
No I don't take credit for his work at all but you like to try and twist words so we'll leave it at that. My customer service is top notch and yes I don't agree with the BS that goes down on tech so I spoke my mind over there and the truth hurts some people. I know of the failure of the power vendors on tech and post the truth without regard. Yes that got be banned. It was a long time coming. there is only so much biting of the tongue one person can do.

Guess what smart guy I don't do anything different than 80% of the engine sellers on that board or this one. Only difference is I aligned myself with one of the very best in the business and am up front open and honest about it. You can get a hold of me 24/6 1/2.. This is what most of the known world does by the way.... retail, distribution etc...

Love how you dance around each time and then attack in a different way. I distribute HKE engines, I don't build them. Not sure why you twist my words but I don't care either. Warn people against my conservative approach all you want, your riding everyone else's work and pointing fingers at me. Go into business and sell engines and take responsibility then come talk to me.

One of my customers broke a Yella terra rocker on Christmas eve and I was talking to him that night and Christmas day to help him out (yes in between my kids opening their gifts) . Erik was on the phone with me. I can name very very few shops that provide that kind of support.

SpinMonster

You dont take credit for his work? You said:

Lots of "WE" in there for someone not taking credit for his engines. You didnt build anything. You sell parts from your house. You dont build for safety....Erik does. You dont build for longevity....Erik does. Why should I check Erik's reputation? You think thats supposed to credit you somehow?

If you're not taking credit for his work then why are you giving examples of his work? How is that "WE" if you didnt build the engine, the car, or the tune? His car and truck that you didnt build or tune has nothing to do with you.

I suppose since I have friends that are major league baseball players it makes me a great baseball player. We are great at pitching... I guess since I use ECS supercharger kits on the cars I build, I can use all of ECS' accomplishments as my own. We build the best S/C kits around!!!.

Erik's spot on an N/A list doesnt support not using meth on an FI car. Lots more heat in FI than N/A. Some of the cars on that list faster than 9.4 have more than 12:1 compression.

Back on topic: Compression isnt evil its a build spec. You run what the build calls for and sometimes thats over 12:1. Meth is a safety tool. All of the tuners I know that build fast cars use it.

RACER7088

Hey just saw this and yes I would always go more conservative in compression than others since safer is better for most shops and individuals. If you have the tuning and conditions and setups with meth for instance you can certainly run more compression but it's all relative. Just depends on how safe you want to be versus making some extra power.

On Chris's engines we do go over everything together and yes they are going to be more conservative on compression unless the customer demands a certain number and then we will try to make that number or get custom pistons to do it if we need to. Most people could care less about another 50 hp on a car that can spin it's tires to 100 mph usually anyway but especially if they have issues.

The pump gas NA cars we do are not over 12 to one and Ashley's car only was at the end after she and Jeff decided to try that and they got basically almost nothing out of doing that which also accompanied a lot larger cam so that last combo was mostly a bust and gained around a tenth and did start hurting the engine as well. Had to send them another piston in fact.

PowerLabs

What a mess... Love how my name gets thrown around here too....
Forget it. I'm going to the bar.

LS2_FTW

old motorhead wrote on camaro5 forums something close to this matter. It is safe to run a low compression ratio because high boost + high cr + wot @ under 2000rpm = boom.... He said GM did a low 9.5:1 cr on the zr1 with the boost it had was cause they had to "idiot proof" the engine. Because too many people would be barrying the throttle at under 2000rpm and with a high cr is a So to me it would just be safe to run @ 9.5:1 with high boost. But to each their own, so just all be careful with your cars and smart!

SpinMonster

I think you clearly missed the point with the posts here. Application applies to your compression level. You are now making the distinction between pos displacement s/c's and a centri s/c. Cylinder pressures even on a pos displacement s/c arent highest at the lowest rpm where full boost is had. Its still at the TQ to HP peak where the cam dictates the peak to be. I think the TQ peak is most troublesome which on the TVS 2300 builds tends to be in the mid 3000's compared to the 4800peak on a centri build. Your point on the pos displacement s/c's is valid though but it simply enforces my concept that the build parameters dictate compression differently.

I think the OP was asking about a centri due to it being a 14lb boost on a 7 liter.

The OP asked about running 14psi on a 7 liter and thats different than a 6 liter. On a 6 liter thats been done without issue quite a few times. I think it dictates the use of meth injection for 115 octane. Displacement, boost level, altitude, and octane dictate the compression you can use. Guy (spinmonster) disagreed with 99blancoSS because 14 psi from a centri s/c on a 6 liter isnt the same boost compression as a 14psi boost on a 7 liter so its not 9.5:1 for all builds. (I dont think that was what 99blancoSS was saying). That peak boost with a centri s/c would only make 2psi at 2000rpms. 9.5:1 compression isnt the FI compression you run far all FI cars although it may very well apply to his 7 liter build if he is at sea level. It isnt one size fits all. If a twin screw or turbo stroker was running 14psi where pump gas is 91 octane, I would drop compression much more...again, application.

10psi on a 6 liter from a centri s/c is fine on stock compression and it makes very little boost down low although I would use meth even at that level for safety. A 10psi max boost will be 1psi at 2000, 3 psi at 3500, 7psi at 5000. Do you think 1psi at 2000rpms requires you to run 9.5:1? I dont and neither would OldMotorhead. My postition is that meth should be mandatory for cars making north of 600rwhp because octane allows the use of more boost safely. I tune meth cars to work without meth and then use meth only to add safety and not tune for meth's use that requires it to work. You have just as much a chance of a meth kit failing as getting a clogged injector or having your fuel system fail. 600rwhp from N/A doesnt have the heat issues from a small head unit near maxxed out on a 600rwhp FI car although its been demonstrated that meth even on N/A cars sees a 20-25rwhp benefit from cooler IATs. Charlie from RPM in california had that result on actual cars as posted by the owners.

Old Motorhea runs a car with no meth. Obviously cars running E85 and meth injection which are 105 octane and 115 octane respectively can run way more compression. One local here is 12.5:1 on his boosted 1600HP methanol car running in the 7's at a DA of 7000' for 7 seasons. Again, application dictates compression.

I think 80+% of the centri kits out there sold by ECS and A&A go on stock engines running stock compression at 10.9:1. I doubt the vast majoriy of them run less than 8-10psi but thats at peak. No issue on stock compression. Now running 10psi on a 7 liter is different but it doesnt need to be as low as 9.5:1 (although on a 7 liter it very well may require it) but at the same time it doesnt need to be as compression sensitive because it is a stroker and low end TQ is easy to come by.

As far as what GM does, thats pretty far from optimum. The ZR1 is a dumbed down build and far from max effort. They build cars that have to run fine at all areas of the world including the south texas heat and south California on 91 octane. That same ZR1 moves like a cam only LS2 at my altitude. One local that dyno'ed on the dyno jet here with his ZR1 was 417rwhp uncorrected with a 1.28 correction factor. I dont think GM does it best.

Its not one size fits all. There are builds that require 9.5:1 compression but 14psi with a centri s/c on a 6 liter isnt one of them. Its a bit low even at sea level.

Posted by Jay

099blancoss

I'll answer all your childish almost naive rhetoric quite simply like this spin and then I'm done with this thread, you don't warrant anything more from me.

When I sell an engine or spec it or talk about one, all of HKE's experience is behind it. SO yes it's we. I benefit directly from his experience and so do my customers. SO again its WE.

If I was trying to take credit for his work his or HKE's name would not appear anywhere in my threads or signature.

I'm out.

glass slipper

The guy you quoted earlier had some good calculations for effective CR...

Unfortunately, he doesn't have a clue how to apply the numbers and they become meaningless. A more useful number than any type of compression ratio number is the pressure ratio but not many people know how to get it. Spin may not know the theory behind the pressure ratio or how to draw a Pv diagram for a centri boosted Otto cycle engine but his experience has taught him all he needs to know in how to apply the pressure ratio...experience is a good teacher. This tidbit from one of his posts is all anybody needs to know:

To give an example of this, when restrictor plate racing came along in NASCAR, it wasn't long before teams started using 18:1 compression and more RPM to just about restore power back to the previous level. That's why NASCAR restricts CR to 12:1 now. The static compression ratio is just a number...there are many variables that determine the cylinder pressure at any particular RPM and a discussion about max CR without taking any variables into consideration is a pretty useless discussion.

TwinSpin

Thanks for the input. I think your work is awesome.

This was an FI thread and Chris took the direction of talking about your N/A accomplishments undoubtedly to lend credit the compression opinion where it really wasnt needed. Many cars on the top N/A motor drag results list are over 12:1 and its simply an application decision. A few in the 8's are very high.

My question was more for FI:

Trying to connect the dots of both the arguing members herin; If a customer was running a 228/232 115 LSA (late closing intake valve taking dynamic compression down a bit from the stock cam) on a 6 liter FI motor with 14psi from a centri s/c at sea level with 93 octane, what compression would you run and is your position that you wouldnt run meth and try to get the most out of it with pump gas even if it was over 700rwhp? Are you opposed to meth injection?

Its not to prove anyone wrong but rather show people not in the know that 9.5:1 isnt required for that boost on a centri s/c on a 6 liter. Im sure you are aware that many people run that boost on a stock compression LS2 or 10.7:1 for an LS3 with no adverse effect, with meth injection. I have a Z06 and wouldnt care to lose the low end for some safety because I have a 7 liter so torque will not be bad anyway. I have no plans to ever build the motor and the soft GM LS7 pistons wont take any abuse for long. Im in the safety camp but there is a level of over-doing it. I do some tuning and would definitely lean on the side of safety for anyone's car.

Thanks again for chiming in.

Jay

TwinSpin

Is that english?

Im a computer/math guy but have no idea what that means.

The Clevite Kid

Then go back to school and get a real mechanical engineering degree.

TwinSpin

Why the attack? Im not a mechanical engineer nor do I want to be at 1/5 of the income. Im an airline employed computer software designer. I do quite well with it.

seevi

I thought the rule of thumb was every 10 Lbs of boost doubled your flywheel HP. A stock 400HP car with 10 Lbs of boost would see 600 HP (again at the flywheel), about 480-500 at the rear wheels.

SpinMonster

14 doubles it but you have to subtract what it takes to spin the blower. So a 450rwhp set-up with a 14psi boost is 900 minus about 150 to spin the unit. 750rwhp is about what a 14psi car sees with a 224 cam as a blower cam.

Most people are estimating high especially on lower compression builds. For example if you use a Z06 cam in an otherwise stock LS2 it isnt going to be anywhere near 450rwhp on its own. A stock head Z06 cammed LS2 would be about 410rwhp and at 14psi it may be 820-150 or about 670rwhp. Thats about the result Powerlabs got on his last build. His compression was slightly lower and his boost was 15psi at peak with the ZR1 cam.

When I first did an ECS kit on my 471rwhp H/C car at 10.9:1 compression, it made 704rwhp on 11psi after taking off the underdrive pulley. My base was likely around 460 at that point. I dropped comrpession to 10.4:1 and went with a 15psi boost and was at 770rwhp with meth. I dont have comparison number for the stroker/ECS2200 build but it went to 822rwhp and 959 on a 75 shot at 14psi. My altitude makes compression comparisons useless. My current cranking compression is 145 so it mimics a car at sea level with 9.6:1 on a stock cam in that respect. Static is at 10.5:1 for my 6800' altitiude. The car is built for here and doesnt come down under 4500feet ever. If it did I would simply pulll the boost back with a bigger pulley. It would still make the same uncorrected power as I drop in altitude with less boost.

ZombieSoldier

what a learning experience this is becoming here...

SpinMonster

Staying warm?

ZombieSoldier

80's/90's at night.... 100's during the day