Turbo Selection

[fiznat]

Dammit, heat. I knew that one too... Good post madbouncy!

[Chezedik]

Okay, so you are saying larger turbos will be more efficient at making flow, and so the adiabatic process is less? I assumed it would be the same any time any amount of air was compressed, but then I guess that the larger volume of the turbo allows it to make the same amount of heat over a larger amount of air, and so the total amount of air is cooler and so more dense. Did I get it? Also, how do you think a lightened flywheel would affect a turbo car in terms of spool-up. On one hand, I would think that the blades of the turbo will maintain inertia regardless of the lack of flyweight and therefore spin of the engine. But on the other hand, doesn't an engine that revs faster, build backpressure faster and then overcome the inertia faster and basically boost at the same RPM but at an actual faster e.t.?

[madbouncy]

Yeah that's pretty much it, it's usually easier for bigger turbos to flow air so they won't make as much heat. But you also have to look at the compressor efficiency and stuff. If you put a large turbo into a really low efficiency and the small turbo at it's peak, you can get the little one to generate less heat. But I'm really new to turbos, so you're better off asking like Ivan or somebody else who has worked on lots of different cars with lots of different turbos. I'm sure he's seen enough dynos to know what really happens and not just what physics and stuff says.

The flywheel will help you out. The only time you'll have a problem with a lightweight flywheel is at some launches. If your car is too heavy then a lightweight flywheel will have a really hard time moving the car. After all, when you let off the clutch the little flywheel is what has all the stored energy from reving up your engine. So when the clutch grabs the flywheel, if the flywheel is heavier it'll keep the momentum and won't bog down as much. Where as if the flywheel is too light, you oculd just end up stalling. You're right about the faster thing, you're turbo will spool at the same rpm but you can get to that rpm quicker with less rotating mass.

[Jookmasta]

go with the str8 T3 or ur 16g if u dont mind welding the different flange to the mani. These turbos will net u ur power goal and should b in ur budget. As for that budget for ur entire kit, just start hunting for some really good deals, cuz its fairly difficult to keep everything under a g these days

[DRIFTEADOR]

less inertial=less load, and less load=slower spool. with a smaller turbo you probably wouldn't notice but for those with larger turbos, don't you spool earlier in 4th gear compared to 1st?

i was reading stealth 316's site and found something weird. according to theis cfm maps a small 16g flows more (520cfm) than a big 16g. does this sounds right? 520cfm is a lot.

[turbo98_240sx]

less inertial=less load, and less load=slower spool. with a smaller turbo you probably wouldn't notice but for those with larger turbos, don't you spool earlier in 4th gear compared to 1st?

I though you didn't build boost in 1st gear if your turbo was correctly sized, because the gearing or something I guess if your turbo was on the small side it would. I don't know for sure but something with the load so it will only create like a pound or 2 of boost cuz of what I forget but I know mine don't make boost in 1st gear

[Chezedik]

Yes, I found the same thing drift, and yes that is where I got that particular map from. Not to mention it has a smaller turbine in and ex so faster spool. I am thinking either t3/t4 or t04e but I need to find out what I can do on a stock block, a guy I know told me he heard of a guy running 380 with a boosted stock block for 60K before he blew (at 180K), and apparently it was ALL in the tuning. He says he found he found it on Zilvia.net so I am going to see if I can find that setup and find out about it, if I do I will post a link. He is supposed to have tuned his own ECU and remapped it to handle that safely. The guy also told me he will reprog. an S13 ECU. I will see what I can find out.

[Chezedik]

Here is a link with a dyno of 400hp stock blockhttp://forums.freshalloy.com/u...art=1

[WDRacing]

I don't know where you guys are getting this info, but you can make plety ogg boost in first gear, my wastegate opens all the time in first and it's set to 12psi...

[DRIFTEADOR]

mine did too but boost came in later. wd, try it in neutral. all i'm saying is a greater load makes for faster spool. I dont know how much a lightened fw would affect it

[WDRacing]

I wasn't saying you don't build boost faster with a greater load, I was stating that the other two guys were way off with the no boost in first gear statement.

[Jookmasta]

i definitely dont build nine pounds of boost in first gear but there is some being made.

[s13sr20chris]

still looking for junkyard turbos? the ford probe has a pretty good turbo. also, there are a few old chrysler products with decent t3's.

[Chezedik]

I don't mean to alarm you, but I think your 'mad tight' SR has turned into some sort of pirate vampire, so be careful. I have pretty much decided that I will be buying the Enthalapy programmed ECU available from Boost Designs. I have decided on this because apparently, he could talk a kia into running 9s. If you don't believe me, check the Secret Services 240sx, apparently, he tuned the ecu, and it's balls out with a stock block. Then I am going to go with the turbo setup on ebay from ssautochrome, which is a gt28rs clone of sorts. Kind of like disco potato, but a little slower spool up, but about 1300 less for the kit, so you do the math. Anyway, from there it has already been done by someone else, and they have figured it out, so seriously, look into that ECU. Let's see, for the same price I could have that, or Jim Wolf, let's see... a guy who boosted a stock block KA to almost 400hp, or MSD injectors and an overly complicated fuel system setup. So, in conclusion, Enthalapy good, me boost muy mas because he figured it out for me.

[Nismo_Freak]

I don't mean to alarm you, but I think your 'mad tight' SR has turned into some sort of pirate vampire, so be careful. I have pretty much decided that I will be buying the Enthalapy programmed ECU available from Boost Designs. I have decided on this because apparently, he could talk a kia into running 9s. If you don't believe me, check the Secret Services 240sx, apparently, he tuned the ecu, and it's balls out with a stock block. Then I am going to go with the turbo setup on ebay from ssautochrome, which is a gt28rs clone of sorts. Kind of like disco potato, but a little slower spool up, but about 1300 less for the kit, so you do the math. Anyway, from there it has already been done by someone else, and they have figured it out, so seriously, look into that ECU. Let's see, for the same price I could have that, or Jim Wolf, let's see... a guy who boosted a stock block KA to almost 400hp, or MSD injectors and an overly complicated fuel system setup. So, in conclusion, Enthalapy good, me boost muy mas because he figured it out for me.

Don't hate on my technical drawing.

[Nismo_Freak]

still looking for junkyard turbos? the ford probe has a pretty good turbo. also, there are a few old chrysler products with decent t3's.

IHI RBH25 < SR T25

[Chezedik]

But I can't find a t-25 map, do we have one in the community?

[hannibal]

Never seen a T25. I assume the S14 T28 is pretty similar to the Garrett GT28 (same specs), but thars as close as Ive found.

[Chezedik]

Yes, t28 is like t25, but smaller. You are supposed to be able to port out the t25 to the 28 and use the different wheel, and I guess it is supposed to be somehow cheaper.

[Nismo_Freak]

Yes, t28 is like t25, but smaller. You are supposed to be able to port out the t25 to the 28 and use the different wheel, and I guess it is supposed to be somehow cheaper.

You can save yourself alot of hassle by just not worrying about compressor maps.

Get a T28, you will make about 250whp at about 10 - 12 PSI which is in it's efficiency range.

Don't make it so hard, you aren't building a F1 engine.

[s13sr20chris]

IHI RBH25 < SR T25

for real? thats what i get for listening to internet claims. thats why i like my garrett stuff. you can usually get a compressor map and sometimes a turbine map. oh, but you wont find either for t22, t25, or t28. so sorry. wish i could but every garrett engineer i spoke with said its not going to be released.

[Chezedik]

bump

[Chezedik]

bump again, what turbo does the z31 use?

[s13sr20chris]

bump again, what turbo does the z31 use?

i believe the earlier ones had a t3 60 trim and the later ones had a t25. the real early t3 units were not watercooled.

[Jookmasta]

you may also want to consider a thunderbird t3. i am currently running one of these. its from an 86-88 auto turbo coupe. 60 trim compressor with .63 A/R exhaust housing................i suggest getting it rebuilt of course.......

[Chezedik]

Well, I checked my cartridge number and it is for the 89-90. But it is my understanding that the Z31 used the T3 and the Z32 took the T25 in the twin turbo. Now, I have never seen a map for the T25, and I am relatively sure that most people have not. But if I do the math, and use the GT25 map, there is NO WAY a T25 could support a 3.0 V6 OHC w/o opening the wastegate after 2K RPM. Hell, the T3-60 is a hell of a stretch. At 15psi it could support the baseline claim Nissan put out. But moreover, I will do the cold side conversion for the T04B-60. This means I can have a turbo, but take my time. Also, it gives me a little room to grow, but with supercharger-like response.

[Chezedik]

Jookmasta, how does your kit perform, what do you have going on, do you have numbers? Apparently, the Z31 and the Thunderbird turbos are the same. That is why I ask.

[Red-KAT]

weard.

I'm using a TD06-20G 8cm if that helps ya out. Running 256whp. I hit 10psi by 3500 which means over 200-250rwtq all the way to redline. at 13psi, on a hot day.

I dont know the best pressure for my turbo... I blow at any type of math. Someone wana chart out my turbo????? please? hehe.

BTW. Watch out for internal wastegates... the 20G only had a 20mm wastegate. If yer running a full 3" exhaust with test pipe you might get boost creep. I had to add an external WG to my setup becuse of that.

[Red-KAT]

mine did too but boost came in later. wd, try it in neutral. all i'm saying is a greater load makes for faster spool. I dont know how much a lightened fw would affect it

I build about 5psi in 1st... And thats right when I loose grip. If I had an LSD and less camber I bet I could make 10psi. (And this is with a fadinza flywheel)

When my WG gaskit blew I could not make any boost in 1st... lame!

[Chezedik]

at the RSR racing website, they have a horsepower calulator, and I used it to find that I had ought to be making 223hp at 12psi, I can only assume that will be at the crank, which will be 178hp at the wheels assuming 20% driveline loss, with bolt ons, almost 200Rwhp. that should be pretty quick. But I am wondering what anyone running a straight T3 knows about how it performs on the KA, would you say it was worth it, or do you wish you could have done something differently?