Cas' 800+ or Bust Build

[VTMongoose]

I'm amazed it lasted this long...it's a testament to how tough these motors really are.

I would go stock compression so you can make more power on 93, but that's just me.

 

[Redline]

I'm amazed it lasted this long...it's a testament to how tough these motors really are.

I would go stock compression so you can make more power on 93, but that's just me.

Practically speaking, this is prudent. Especially if you're taking long trips and don't have access to extra ethanol or methanol. But if you're just going to be in your local neck of the woods and always running eth and/or methanol, you'll get a good deal more baseline power from higher compression pistons and not have to worry about knock issues.

 

[alexwlwsn]

I would go stock compression so you can make more power on 93, but that's just me.

That's what I found in my searching. You seem to need more octane to get to the same point with high compression but it's good for pushing a setup to the ragged edge.

 

[VTMongoose]

10.5:1 would probably be OK on a K04, but my understanding is that the nature of running a big turbo is you need a high wastegate spring pressure, so you might not be able to drop down the boost pressure enough to accommodate the higher CR.

Also honestly I hate to be the one to rub salt in the wound here but really @CMajor you should have planned things better. Not having the money for an engine or at the bare minimum a backup car in the event this build ZZB's was bad, especially in light of the fact that it was a ticking time bomb.

 

[Redline]

10.5:1 would probably be OK on a K04, but my understanding is that the nature of running a big turbo is you need a high wastegate spring pressure, so you might not be able to drop down the boost pressure enough to accommodate the higher CR.

Also honestly I hate to be the one to rub salt in the wound here but really @CMajor you should have planned things better. Not having the money for an engine or at the bare minimum a backup car in the event this build ZZB's was bad, especially in light of the fact that it was a ticking time bomb.

The alternative is to run a 4-port EBCS. Then you can run only ~7-8psi spring pressure and have the WGDC headroom to get to ~30+psi or so (usually, it's about a factor of 4x spring pressure or so @ 100% WGDC; 3-port generally offers a factor of about 2x of base spring pressure @ 100% WGDC). An added benefit of this approach is it's a lot easier to tune for actual traction in 1st and 2nd again, LOL.

I'm actually planning on converting when I build and do all the other stuff. Having traction in 1st and 2nd is a unicorn for our cars that most of us don't enjoy. Having at least a partial chance of performing well from a dig is a very desirable trait for our platform, even at power levels as low as fully bolted stock turbo setups. As it stands right now, no matter how hard I try, I can't properly modulate the throttle in 1st and 2nd. It's either total wheelspin, or very little actual power being put to the ground. A properly-setup 4-port/tuning strategy will directly, and likely very effectively, address this.

I wonder: any drag-strip guys in here using this approach? Seems like a no-brainer to me. For us "regular" (non-drag-strip) folks, at least cars we're much faster than won't think we're no challenge at all because all they do is dig with us, LOL.

 

[alexwlwsn]

10.5:1 would probably be OK on a K04, but my understanding is that the nature of running a big turbo is you need a high wastegate spring pressure, so you might not be able to drop down the boost pressure enough to accommodate the higher CR.

I dont think this is too relevant considering he's doing a balls-out build. Plenty of people have no issues with high-comp pistons and a normal (~15psi+) spring on their wastegate. It's really just a matter of the best spark advance vs. compression vs. boost levels on normal compression vs. a high compression motor. You tend to need a little less spark/boost on high comp to make the same power but then will need more octane I believe.

He did only mention the compression specs of his pistons once though so I'm sure he hasn't made his decision yet. I am just curious that IF he does choose 10.5:1, the logic behind it. (not saying it's a bad thing in the slightest)

 

[Redline]

I dont think this is too relevant considering he's doing a balls-out build. Plenty of people have no issues with high-comp pistons and a normal (~15psi+) spring on their wastegate. It's really just a matter of the best spark advance vs. compression vs. boost levels on normal compression vs. a high compression motor. You tend to need a little less spark/boost on high comp to make the same power but then will need more octane I believe.

He did only mention the compression specs of his pistons once though so I'm sure he hasn't made his decision yet. I am just curious that IF he does choose 10.5:1, the logic behind it. (not saying it's a bad thing in the slightest)

Maybe it's different on a 6466, but on my BNR S3, the 14psi spring pressure is way more than enough to elicit great plumes of tire smoke (and very little traction) in both 1st and 2nd. And my EFR7163 will be able to generate much more boost much more quickly than even a K04. I don't want tire smoke; I want acceleration. I'm the kind of guy that rendering 2 of our 6 gears essentially WOT-useless doesn't make sense to. 4-port seems the only feasible option

 

[alexwlwsn]

Maybe it's different on a 6466, but on my BNR S3, the 14psi spring pressure is way more than enough to elicit great plumes of tire smoke (and very little traction) in both 1st and 2nd. I don't want tire smoke; I want acceleration

Don't forget BT power curves are very different from what a BNR will give. Based on wanting a 6466 I dont think @CMajor is very interested in having torque on tap like a BNR. That later/slower spool prevents the tires from just blowing up.

Mind you though he will still need serious tire to put that power down on the street.

 

[Redline]

Don't forget BT power curves are very different from what a BNR will give. Based on wanting a 6466 I dont think @CMajor is very interested in having torque on tap like a BNR. That later/slower spool prevents the tires from just blowing up.

Mind you though he will still need serious tire to put that power down on the street.

Right, I noted that in my comments
But also, like I said, if/when I go EFR7163, my turbo will spool faster than even a K04 (and with the top-end of a GTX3076r - next-level F1 turbo tech FTW!!!), so it is an issue I'll have to face in the future. Most BTs won't have to deal with this; EFR7163 owners will have to address it, if they care about having a useful WOT in 1st/2nd, that is...

 

[CMajor]

I'd be interested if you could explain your reasoning when you choose the compression of your pistons. There's a lot of back and forth on when high comp is necessary and about what the trade offs are I feel.

I only spoke with Mark briefly about it but I would be running a 12.5:1 ratio and looking down the road to experiment with some cam setups that he has in mind. From what I've read you need an after market cam with a higher lift to maximize the benefit of high compression pistons so I would like to get a baseline with stock cams and then swap in a custom set that he has in mind for testing. Ideally get a company to develop cams for the platform or a group buy of some sort if others are interested.

Also honestly I hate to be the one to rub salt in the wound here but really @CMajor you should have planned things better. Not having the money for an engine or at the bare minimum a backup car in the event this build ZZB's was bad, especially in light of the fact that it was a ticking time bomb.

Like I said I normally have money set aside for emergencies but proposing was more important to me than thinking about my car. I do have access to other cars to drive if I need them, thus the Camaro and Civic that I mentioned. I'm not selling the car so I'm not that bad off lol.

Don't forget BT power curves are very different from what a BNR will give. Based on wanting a 6466 I dont think @CMajor is very interested in having torque on tap like a BNR. That later/slower spool prevents the tires from just blowing up.

Mind you though he will still need serious tire to put that power down on the street.

Exactly, I don't care to have the low end torque like the BNR guys. I honestly love the way a BT drives over a small to medium sized turbo, I feel it's better for a daily IMO. I'll probably have to fit some 275s up front to have any sort of traction on the street haha. I know Devin Saunders ran around with street legal radials of some sort, that may be what I have to do for traction.

Maybe it's different on a 6466, but on my BNR S3, the 14psi spring pressure is way more than enough to elicit great plumes of tire smoke (and very little traction) in both 1st and 2nd. And my EFR7163 will be able to generate much more boost much more quickly than even a K04. I don't want tire smoke; I want acceleration. I'm the kind of guy that rendering 2 of our 6 gears essentially WOT-useless doesn't make sense to. 4-port seems the only feasible option

I'd be interested to see the 4-port setup, I'll have to do some research on that to see what it's all about!

 

[VTMongoose]

As it stands right now, no matter how hard I try, I can't properly modulate the throttle in 1st and 2nd. It's either total wheelspin, or very little actual power being put to the ground.

It's definitely not the easiest thing to do. I've found interpolating the values in the bottom 4 rows (WOT conditions) of my WGDC down to pretty low throttle positions helps a lot. A lot of tuners, Cobb included on their OTS maps, have this big "shelf" of power you can feel the second you dip above 75% throttle or whatever it is. It gets really annoying when you're trying to gradually roll on the power.

I honestly love the way a BT drives over a small to medium sized turbo

I always find it interesting how different people can be in this community even though we all own the same car. There's no way I could give up the low end torque I have in the BNR. It's part of what makes the turbo and the whole car so much fun for me.

@Redline totally forgot about the 4-port option. That would definitely be worth investigating for OP.

I dont think this is too relevant considering he's doing a balls-out build.

True that, but many with heavily modified cars still drive them long distances. @phate ran a high CR setup and mentioned to me once that it was annoying having to carry around E85 all the time. Just trying to help save OP the same annoyance. 12.5:1 is pretty high.

 

[Maisonvi]

Didnt everyone who tried a 4 port a while back abandon it? I dont remember exactly why, but it wasnt easy to control or something

 

[Sho]

Didnt everyone who tried a 4 port a while back abandon it? I dont remember exactly why, but it wasnt easy to control or something

Something about the frequency its on doesn't play well with the car. @Realgib3 tried one a few years back, I believe.


As far as having to run corn with high compression, and it getting annoying ; that's gonna depend on the person. I haven't had a 93 octane tune for my car for the past 90k miles and haven't run straight 93 octane for well over 100k. All depends on how committed you are to the corn lol. It does suck planning road trips around e85 stations and how many jugs you can fit in the car, though

 

[Mauro_Penguin]

Yes they did. PapaSmurf sold his, he'll I think RealGib3 ran one. Something about a different operating frequency.

Nishan made a little breadboard project to get the 4port to function better and found that there was some behavior while daily driving he didn't like. In the end he said it was not worth all the effort and to just keep the 3port. I forget all the details but it's on MSF somewhere.

 

[Sho]

Idk if relevant, but I do run a 9psi spring in my pw46 ewg with a 3 port Ebcs and hold 35psi at 7500rpm without issue at 85% wgdc in hot and humid weather. Probably not ideal, but it works. Then again my exhaust is quite free flowing and it only took 10% wgdc to hold 22psi at 7k+ when I was stock block and on stock fueling, and just on spring pressure, I do get a good 5-6psi of creep up top.

Tuning wise, I am boost limited in 1st and 2nd gear and 3rd could be dialed down if I needed it. Although I don't really have traction issues in 3rd unless it's colder outside, so it's seeing full boost like I would in 4th gear

 

[alexwlwsn]

Exactly, I don't care to have the low end torque like the BNR guys. I honestly love the way a BT drives over a small to medium sized turbo, I feel it's better for a daily IMO. I'll probably have to fit some 275s up front to have any sort of traction on the street haha. I know Devin Saunders ran around with street legal radials of some sort, that may be what I have to do for traction.

I agree with you on the driving manner of a BT car vs. a KO4/BNR car. it's very reasonable around town since you aren't on boost often and at least in my opinion the BOV opening with every shift gets annoying with smaller turbos.

I run a 245/40R18 Nitto NT01 and when warm they'll get very very close to hooking second at 573whp. I might pick up a set of 17x9s soon and see what a 255 or something will do but it's a really great tire. They're not too loud and even in the wet they hook well.

True that, but many with heavily modified cars still drive them long distances. @phate ran a high CR setup and mentioned to me once that it was annoying having to carry around E85 all the time. Just trying to help save OP the same annoyance. 12.5:1 is pretty high.

I run an e40ish mix (5gal E, 5gal 93) and I've never been too annoyed carrying around ethanol. I do have a station 18 miles from my house though so when I need to stock up, it isn't much of a bother. I haven't had the situation yet where I took my car on a long trip since it was tuned on ethanol so I can't really comment on that though. It does sucks living in an apartment though because I can't exactly keep 50gal of ethanol in my living room.

 

[CMajor]

@VTMongoose To each their own with what they prefer haha. Like @alexwlwsn said, being able to stay out of boost when I want to is nice as a DD for me. I get the other side of it and who knows I may have preferred a smaller turbo if I was tuned by someone who knew what they were doing when I first got my car. A small/medium turbo doesn't really satisfy my goals for my car which is the number one reason. I kept up with a new Z06, yeah he was pulling away but I didn't do that bad against him considering where my car was. I'd ultimately like to beat cars like that with a car that costs a fraction of what they paid and get the satisfaction that they are thinking to themselves "What the hell is that thing?!". E is plentiful where I live so I don't have to worry about that plus I'm looking at getting a new car at the beginning of the year so I don't have to take my speed on road trips. I have taken the speed on roadtrips before and I just carry a few jugs with me if necessary.

I run a 245/40R18 Nitto NT01 and when warm they'll get very very close to hooking second at 573whp. I might pick up a set of 17x9s soon and see what a 255 or something will do but it's a really great tire. They're not too loud and even in the wet they hook well.

That's awesome, I'm still running the stock tire size so I lose grip in third when the aux kicks in on Nitto NT05s, unless they are very warm then they usually hook. On the plus side of that my car is a complete sleeper until I go WOT haha.

 

[Realgib3]

Just because there's so many comments in the last day, I'll skip quoting everything and just respond to some of the big topics I saw.

1. Everyone's theoretical thoughts on the cons of High Comp are valid, however, running 450+whp on decent 93 octane alone was easy on the 12.5:1 pistons. Between DI cooling and AUX cooling, it's not a problem at all with a proper timing tables. Also, 99.99999% of guys running Aux fuel are zero % concerned with trying to make max power on 93 alone, so a map that makes the car quick on 93 alone is plenty.

2. Using HCR pistons to this degree nets a completely different feeling in the way the car behaves during normal driving, out of boost. This is more important that any other "pro" for the HCR. In simple terms, imagine your car currently makes 165whp/130wtq on a standard compression, stock motor. Now imagine how that same NA engine would feel at 210/170, huge huge difference.

3. Pros of truly HCR (12:1+) - Much more responsive off boost and street driving/transient response situations, better gas mileage, more power per psi boost.

4. ST vs MT vs BT - I have a post/picture in another thread about this, but in real life, looking at TQ per rpm, average TQ, etc, it's hard to argue for a small or even medium turbo (<3076 size), all else being equal.

5. 4 port will not work with our ECU, without an external board to modify the Frequency. With that said, 3port is plenty sufficient and if you're trying to run super low power in 1st gear, there's ways to run well below spring pressure anyway, so super soft spring isn't necessary.

 

[Redline]

Response moved here http://mazdaspeeds.org/index.php?threads/open-tuning-turbo-theory-discussion.3332/page-2 to keep CA's thread clean.

 

[CMajor]

So I got quite a bit done on the car over last weekend. Installed my new SBC camber arms, 1000% better than the JBR ones. Thought this was an interesting comparison between stock, SBC and JBR. I was a noob when I bought my JBR parts. I think that was the first thing I did to my car, coilovers and camber arms.

Basically removed the entire front clip and now I just need to remove all of the wires so I can start unhooking the 6th port to get it ready to sell. Also I didn't realize how messy draining the coolant would be, it splashed everywhere haha. Now I haven't decided yet if I wanna pull the turbo now or just wait till the engine is out. I feel like it'll save me some annoyance if I wait till the engine is out but I also want to get it out so I can post it up for sale. Decisions....
Here's the before and the after is below to where I got with the car. I'm pretty happy with where I got considering I've never done this before.

Also I was messing around after I finished all that and took my front bumper apart to see how the grill fits. The fitment is shit but I pretty much knew that when I bought it and it's just going to be used as a mock up of my eventually carbon fiber grill so I'm not too worried about it.