ZCar Forum banner

Status
Not open for further replies.
1 - 14 of 14 Posts

·
Registered
Joined
·
1,991 Posts
Discussion Starter #1
I found this on SDS website, and it could'nt be anymore true: We talk to thousands of people every year with regards to EFI systems and modified engines. We get many people who just have to build a high compression turbocharged street engine. Even though we strongly suggest lowering the compression ratio, many people insist on 9 to 10 to 1 CRs. Usually these people phone back with sob stories of lots of pinging, blown head gaskets, melted plugs and pistons. We dispense free information based on 25 years of performance engine building experience to help people save money and disappointment. We frankly see very few high compression turbo engines running on pump fuel lasting more than a month before they fail. This is why you don't see any high power factory turbo cars with 10 to 1 CRs. Stick to under 8.5 Crs and you will make more power and have higher reliability.

So.. After reading this, Would you put a turbo on a 9.5:1 N/A block?

Food for thought........



Post Edited (Aug 13, 11:43pm)
 

·
Registered
Joined
·
17 Posts
Re: Can I run a turbo on a N/A Block?

You can. Just be careful when tuning. Intercoolers = good, detonation = bad. just don't go too wild on the boost. Stock boost should be fine and fairly reliable, just use good gas (93 octane). If you get detonation, back off the boost or retard your timing.

Brian

Turbos don't kill engines, stupid people pushing too much pressure kills engines.
 

·
Registered
Joined
·
3,080 Posts
Re: Can I run a turbo on a N/A Block?

<http://www.redz31.com>

He's pushing big time 400whp+ power on an NA block.
 

·
Registered
Joined
·
1,359 Posts
Re: Can I run a turbo on a N/A Block?

wait so i shouldnt put a turbo conversion on my n/a engine
 

·
Registered
Joined
·
17 Posts
Re: Can I run a turbo on a N/A Block?

Jason turbo'd his NA and he's pushing 400HP on 9.0 compression pistons (stock). Just don't be stupid and crank the boost too high without taking into account fuel limits and compressor efficiency. I believe the stock t3 is out of it at about 13-15 PSI
 

·
Registered
Joined
·
1,991 Posts
Discussion Starter #6
Re: Can I run a turbo on a N/A Block?

Dont you understand... you must retard timing, use cold plugs..ect.. to even allow boost at all with a higher CR. If it more efficiant to run lower boost and a more advanced timing setting take this for an example.

7.8:1 compression engine @ 7 psi of boost and total timing @ 35 BTDC

This is a pretty close example of a Vg30et and our ECU total timing values up to 6000 rpms.These are relativley safe efficant levels for long life. It is reasonable to assume that this engine will produce power well within safe levels before you reach detonation.

Dont forget that we can only get 92 oct in most places. on a given fuel, the maximum and mean cylinder pressures that can be achieved are limited to the knock limit. Trying to achieve cylinder pressures above the knock limit WILL kill the engine. At wide open throttle, cylinder pressures can be altered by changing boost pressure and ignition timing. If the knock limit on a given fuel occurs at 600 psi PCP(peak cylinder pressure), this limit could be achieved by using 7 psi of boost with the timing set at 30 degrees BTDC or at 12 psi with the timing at 15 degrees BTDC. The engine will be considerably more efficient running less boost and more timing and the thermal stresses will be reduced as well.

So why would'nt just go the extra step?? Youre car could handle higher total timing in the ignition maps, Which means the engine with lower Compression Ratio can produce more power , SAFER, and more efficiant.

Quote from catman:

You can. Just be careful when tuning. Intercoolers = good, detonation = bad. just don't go too wild on the boost. Stock boost should be fine and fairly reliable, just use good gas (93 octane). If you get detonation, back off the boost or retard your timing.

That is not how you make power, who wants stock boost for the most part?

I know you can do it, but if you think that 2 engines (both properly tuned)
will produce equal power , you are mistaken. Then lower CR one will produce better, more reliable power each time.

Long story short... Lower CR allow, higher boost levels, more agressive timing curves, ending in more power. with readily avalible fuels.
Sorry about the long post!! :)

l



Post Edited (Aug 16, 9:25am)
 

·
Registered
Joined
·
1,359 Posts
ok so does that mean you can put a turbo on the n/a block or not, u were really technical
 

·
Registered
Joined
·
5,263 Posts
If you don't understand this 300zx1985 you don't need to be attempting to do a turbo swap on your n/a. As I told you before it can be done but it's a lot more involved to make it work properly than just to drop in a turbo engine. If you want a turbo set up either drop in a turbo engine or sell your car and buy a turbo. Realize that you'll probably end up spending the same amount on the conversion as just buying a complete good running condition 300zx turbo. So it's probably more praticle and logical to sell your car and start over.
 

·
Registered
Joined
·
1,359 Posts
yeh man ur probably right i just want a fast car, i mean my truck is faster than my z. but i cant sell it man like i just bought it dude
 

·
Registered
Joined
·
1,593 Posts
If all you want is a fast car then sell the Z and get 5.0 mustang for $500 and put the rest into modifications.
 

·
Registered
Joined
·
5,263 Posts
LOL, Red beauty has a point. The way I see it you have two options. The first is you sell the car and buy something else like a 300zx turbo. The second option is to do the turbo swap. The first option shouldn't be that hard to do. You just bought the car so sentimental value is very low right now. Sell it and buy a 300zx turbo. I honestly don't see what you can't. It will probably cost you double the amount to pay a mechanic to do a turbo swap than to just buy a good running 300zx turbo. Selling and starting over will be much cheaper. Now if you want to be stuborn about it that only leaves option two. If this is what you are going to do make sure you do it right which means dropping in a complete turbo engine with the appropriate parts. As I mentioned paying someone to do this for you along with the cost of parts is going to be more expensive than just selling and buying a turbo. It's your choice but don't half ass things. Chances are since you don't know anything about these cars you'll turbo charge your current non turbo engine and blow it, then where will you be.
 

·
Registered
Joined
·
248 Posts
these are some ridculous comments/answers... higher compression (9:1) compressions does not mean that you will make less power...that is completely wrong..it does mean you have to change timing etc, but that doesn't mean less power and less aggresive curves...I'm not even explaining any more...oh actually one more thing... 2 Z's...both turbo'd running 14psi, one with n/a pistons one with turbo pistons...the n/a will produce more HP at the rear wheel by more than just a few HP...and same driver in the quarter mile will do better with the n/a..so there
 

·
Registered
Joined
·
1,991 Posts
Discussion Starter #14
You are missing my point, never said it wouldnt work, or produce power, I am stating that lower CR's produce better reliability, and better tuning results, if you think that higher compression ratios are the way to go, you go right on ahead and do it!! (i see you have) But if it was a better way to go, then why do manufactures build turbo engines with lower CR ratios, than N/A engines? Answer that simply ,there is a reason.



Post Edited (Aug 16, 9:21am)
 
1 - 14 of 14 Posts
Status
Not open for further replies.
Top