I'm looking for a turbo mentor

[zeiss150]

Hey Z people, Merry Christman everyone!

 

I'm looking for someone with a turbo Z that has at least 9:1 CR. I've been reading my a$$ off on the old posts about turbos and high CR and it's just left me with more questions than answers. So I'm looking for someone that has a 9:1 CR turbo that can walk me through the do's and don'ts of that kind of set up.

 

Anyone up for it?

 

Rock on Z people

 

thanks Matt

[hoov100]

i wouldnt really want to run a C/R of 9:1 with a turbo, i try and stay in the mid to high 8's.

[zeiss150]

yeah I know 9.2:1 is high ... but it's what I've got ... so without putting on a P90 ...

[oinojo]

yeah I know 9.2:1 is high ... but it's what I've got ... so without putting on a P90 ...

 

if changing the CR is out of the question then i would strongly suggest finding a reputable tuner, colder plugs, and get the best gas possible.

[zeiss150]

let me lay down what ive got planned and then everyone will know where im at. Ok ... from the top down

 

schnider cam 270, 460, with performance springs new nissian rockers and lashpads

N42 head

N42 intake manifold with 380cc svo injectors

60mm TB (one inch spacer)

custome fuel rai

2mm HKS head gasket

F54 block with flat top pistons (ballanced rotating mass)

stock exaust manifold

Z31 rebuilt t3 turbo

21/2 in down pipe (o2 sensor) to 21/2 inch exaust ending in turbo exaust

intercooler (a good one... not sure what kind just yet)

megga squirt

280zx turbo dizzy with CAS

Z31 maf

Megasquirt

and maybe some other stuff I'm forgetting

 

Ok now you know what I have in the wings I already have the block and head running really well with SU's but now I wanna go turbo with out changing to a P 90 so Im looking for someone with a similar set up... anyone?

 

rock on Z people

[cheftrd]

http://www.sdsefi.com/techocta.htm

[zeiss150]

Great info. Thanks Matt. I live in So Cal and all we have here is $hitty 91 oct so all of my power is gonna have to come from engine mangament and great IC. Im thinking 10:1 AFR. But that is why Im on a search for someone that has done it and what they had to do and weither or not it was worth it. should I just buy a P90 and drop down to 8.61:1 ....

 

Anyone? ... Anyone? .... Buler... Buler?

 

Rock on Z people

[Guest bastaad525]

if you're stuck on 91 octane especially I'd aim more for mid 8:1 a/f ratios.

 

You can do 9:1 but this is gonna limit the amount of boost you can run as you already must know, also yeah tuning is gonna have to be VERY careful or you're gonna risk damage.

 

Don't forget that a lot of people have given some very good reasoning as to the P90 head being better at preventing detonation vs. an N42. I would never even THINK of running an N42, high compression turbo setup. I'm sure it can be done but how much of that power and responsiveness gain from the higher CR are you gonna have to give up to running really rich and way retarded timing plus having to keep the boost lower than you should?

 

I mean if you're goal is to have a really torquey responsive car OFF boost but one that will be limited ON boost then go for it... I'd rather have a very docile off boost driveability with the potential to make the really big power safely when I decide to put my foot down.

 

I say P90 and mid 8:1 all the way.

[briann510]

We are upgrading to a turbo and will be running approx 9.3:1 compression with a 2mm head gasket. We plan on 550 hp with 115 octane racing gas (I know you are looking at pump gas only though). We have too much money in our J&E pistons and Carillo forged rods to change them out so we are going with the same stroker 3.2 and just adding the turbo electronics and mechanicals to it.

[zeiss150]

my goal for my turbo project is 275 -300 rwhp in a daily driver that wont blow up on 91 oct. If I could drive up to shell or mobil and get 115 oct for $2.25 a gallon... well then I'd be looking for 400hp. I know I can turbo the 9.2:1 CR that I have but, is ANYONE DOING IT OR DONE IT? Putting on A P 90 isn't out of the question its just sort of one more thing that I would have to do that I don't want to have to do.

 

Thanks for all the great responces ... keep them comming

 

Rock on Z people

[GrayZee]

Just a comment on the list of parts you have (or plan to have) You said a z31 T3, well.. if you want 275 to 300hp then you'll need a bigger turbo.

 

It will be that much easier to achieve your HP goal with a 3" exhaust rather than a 2.5"

 

You also mentioned that have a z31 maf, and wanna use megasquirt. Well megasquirt uses a built in map sensor. No need for the z31 maf.

 

If you have a z31 maf and a 280zx dizzy with CAS, then you could also consider using a z31 ecu.

 

If you want to run a really high CR (which I'm not advising) then I would consider running a good intercooler AND alcohol injection. The alcohol will just be another safety factor allowing you too push it just a little further. (by how much I don't know) but it would be nice to have at any rate.

[zeiss150]

Thanks GrayZee, See thats the Kind of Info I need a mentor for... When It comes to a N/A engine I do pretty good ... but I don't know $hit about ECU's and map and maf and cas and all of thoes other abriviations (I know what the abriviations are I just don't know how to apply them). So far you guys are really talking me into going with a P90:(. If I did switch over to a P90 I would be running it with a HKS 2mm head gasket and a 20thou over bore giving me a 8.07:1 CR... to low? If I use the stock head gasket then I get 8.61:1... to high?...

 

The search for a 9.2:1 CR turbo Z daily dirver with 275rwhp on 91 oct goes on!

 

Rock on Z people:rockon:

[SHO-Z]

This is some good reading on the basics.

 

Engine Compression

There are a couple of areas in which optimizing an engine for naturally aspirated power and forced induction power are at complete odds with one another. Static (engine) compression ratio is one of those. Most musclecar enthusiasts are readily aware of the fact that increasing the compression ratio of a naturally aspirated engine results in more power per unit of fuel combusted. The amount of engine compression that can be run is limited by the fuel octane that will be used.

 

Forced induction engines are fundamentally different in that two sources of compression are available: the compressor and the engine. Effective compression is the term often used to describe the impact of the external compressor on the combustion efficiency.

 

So how does a lower static compression benefit a forced induction engine? Let's look at an example. Compare these two situations:

 

1) On a stock 5.0 with ~9:1 static compression it is found that a non intercooled supercharger can run a maximum of 9psi of boost without detonation. The effective compression is ~14.5:1 and 320 peak rwhp is produced.

 

2) Same engine/supercharger combination but with low compression 8:1 pistons installed. It is found that a maximum of 13 psi can be run without detonation. Effective compression is again ~14.5:1 but significantly more air is allowed to enter the combustion chamber. Peak rwhp is now 380. In both cases the same octane fuel is used.

[zeiss150]

Great info sho-Z ... I'm glad that this thread is interesting for you, I hope that it is interesting for a lot of members.

 

Keep the posts comming ... still looking for the mithical N-42 turbo Z.

 

Rock on Z people

[Guest bastaad525]

I dunno about the Z31 T3 but I know there are a handful of guys here who have gotten in the 275 whp range on the stock L28 T3, achieved at around 15psi or so. So it can be done. I'm not sure if the compressor or turbine on the Z31 T3 are any different.

 

But to get that 275whp you'll need all the supporting mods, full 3" mandrel exhaust, big bore throttle body, stuff like that. With megasquirt it should definately NOT be a problem as people have gotten more than 200rwhp at 7psi on megasquirt, and someone just made close to 300 I think at like 14-15psi? I know Garrett76zt made 275 on STOCK fuel injection with I think just 370cc injectors and all the supporting mods.

 

But yeah again I say you'd be much better off going with a P90 head and getting compression down into the 8:1 area. Really a head swap doesn't even take that much time, me and a friend pulled and replaced my head in like 3 hours... easy stuff dude. Much easier than having to rebuild the engine from too much CR and boost. Unless you have a tuner that you trust 110% that you know is familiar with megasquirt and can handle a relatively high CR turbocharged car.

 

By the way to answer your question yeah someone here has done a high CR turbo motor I think he was at 9:1 as well... I can't remember his screen name but he stands out in memory because he was having problems blowing head gaskets

 

Does anyone remember who that was? It was like 3 months ago he posted about blowing his gasket.

 

EDIT: By the way, Loose_Screws was the member who just made 292 rwhp on the stock T3 running megasquirt, at 14psi of boost. So it CAN be done. Couldn't find the guy who was blowing head gaskets from high CR though.

[zeiss150]

Thanks Basstad, Great info. I can replace the head with out much trouble(I've got skills:lamo:). I just have a lot of money in my N42. I thought the T3 was up for the challenge... its nice to hear supporting info.

 

Rock on Z people

[Guest bastaad525]

it's been great that some guys running MS have finally been posting numbers... for a long time it was this big question just how much, if any, performance gain MS would be good for over the stock EFI. While only a few guys have dynoed thus far with MS on relatively stock setups (read: stock T3), they have shown consistent, significant gains vs. stock EFI at the given boost levels.

 

292 rwhp at 14psi is amazing... most people would only get about 250ish at 14psi, and as I said, Garret got 275 at 15psi but with a lot of supporting mods.

 

Well... depending on how much money you have in that head and what kind of work, you're options could be to sell it to recoup some of your investment, or yeah you could try to use it. But, what cam do you have in that head? You say you've invested a lot, so I'm gonna assume it's NOT the stock cam. Keep in mind a high performance N/A cam is not necessarily going to perform well on a turbo car. Things like valve overlap can have a big effect on how quick your turbo spools and stuff like that. So there's more reason why you might NOT want to go with the N42 that you have now.

 

Well you can always try it if you really want to? Someone out there has run boost on relatively high CR, maybe not on a Z, but some other setup, that might know better just how much boost would be safe, or how much timing retard or rich a/f ratio you would need. As I said I think there is only one HybridZ member that I can remember ever seeing who's run such a high CR turbo and he was having problems.

 

You could always use that build up head as an excuse to build another Z heheh....

[GrayZee]

I know you can get more than 250hp from the L28et (I'm probably at 260hp myself) I was just saying that a person that wants 250 to (300) hp probably should start with a bigger turbo. Especially when running high CR ratio's remember that a smaller turbo will create more heat the harder it is pushed, and that means hotter air to enter your engine. I remember reading that Scotty got 300hp on a stock T3 but did not advise trying to repeat that, especially if they are looking for reliability. There is also the point that he said z31 turbo, well correct me if I'm wrong, but didn't the 87+ z31 come with a water-cooled turbo? I think that those were only T25's

[BayAreaZT]

I have a stock P90A I'd trade for your N42. I'm in NorCal though.

[510six]

Two words methanol injection

 

http://www.snowperformance.net/