Was wondering if anyone is running a ld9 at 20psi. Was trying to get some recommendations of what kind of turbo to buy. Any and all input is appericated(first turbo project). Thanks guys,
Scott T.
that is a lot of boost for a normailly N/A car. you would need fully forged internals and numerous other things to even come close to making that possibe...
Veritas Aequitas
if it gives you an idea... if you do the math and research, boosted2point4 last i saw was only running 12-15 lbs breaking the 400 hp mark.
I will prob end up running 15psi but I have planned to get new pistons, rods, and valves. But yes I know that is a termendous amount of boost.
i think the GT3076 seems to be the preffered turbo for highly boosted LD9's.
Dose anyone have a suggestion on some reading material to learn about boosting cars.
you can read the sticky at the top of the forum, pick up this
book
20psi is 20psi, the proper question is how much hp you are looking to make, for example 20psi on say a 16g turbo you'll make 380hp, 20 psi on a gt42r and you'll make 520hp(these are made up #s)
i made 448whp and 42xwtq on 20psi from a 60-1, all the mods in my profile where current for those #s beside for the injectors
R.I.P. Brian Klocke, you will never be forgotten
I am looking to generate about 350ish hp, at least 300hp but don't really want more then 400hp. I probably wont have to run more then 15psi but was shooting big.
if your looking for reading. i was suggested "maximum boost" by another member, and i found it very interesting. ALOT of information, all the formulas you need, well... pretty much most of the base knowledge you need to build up a turbo system.
20 psi is a tremendous amount of pressure.
The first question you need to ask is not how much power you want to make...
It's where do you want to make it in the powerband. This is directly related to what you'd like to do with the car. Daily drive it? Autocross? Circuit track? Drag race?
Makes a big difference in making the important primary decisions.....
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Daily drive that can be used to autocross is what I am looking to achieve. I am setting my final goal to be 20psi, but yes i know that is a ton of boost, it will probably end up around 15psi. This is my first project car and I will be leaving for the Air Force on the 22nd, just trying to gain as much knowledge before I have more money to throw into this car.
420hp/350trq from 15psi out of a GT35R.......
SPD RCR Z -
'02 Z24 420whp
SLO GOAT -
'04 GTO 305whp
W41 BOI -
'78 Buick Opel Isuzu W41 Swap
What injectors generated that hp? Also any other mods or just turboed? Also do you guys bore cylinders or leave them stock. Was thinking stock so you have thicker side walls to hold the higher boost.
my cylinders were kept OEM spec. Just JE slugs, eagle rods, a non-GM(acdelco) oil pump that was cleaned up nice was all the bottom end work on mine, "basically".
-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party
My pistons are .040" overbore to lower compression so i put more boost to the engine without running 100+ octane all the time.
Use this as an example as to how much room you have to bore out the cylinders. the quad 4 block has essentialy the same specs as to deck height and things like that of the LD9 block. only main differences are the bore size and stroke. most importantly is the bore size.
The LD9 bore is 90mm where as the quad 4 bore is 92mm.
there is quite a bit of room for you to bore out the cylinders if you wanted to.
SpeedRacerZ wrote:420hp/350trq from 15psi out of a GT35R.......
but that turbo has a lot of lag, don't think it would be too good for auto X...
Veritas Aequitas
So you think i should bore it out to lower compression when adding high amounts of boost, so it will run on lower oct gas.
SS valves are pretty much an essential part that you will NEED for 11+ PSI...that is, if you want your build to last longer then 4-9 months.
Personally the .074" thick HeadGasket is the way to go if you want to shove tons of boost down your little LD9's throat.
20 PSI, .074" thick HG, Wiseco 9:1 .020" overbore pistons. Sounds like a build that could run on pump gas with a good tune.
Is twenty PSI really that much? I know the Honda boys and the Toyota crowd run MUCH more. I'm shooting for 12psi in my ride for DD.
depends on the turbo for 20psi. Thanks for the info guys.
Fel Pro Engine Gasket Set Complete Upper and Lower
Do they make a difference (assuming to get them since i have 178k miles on the engine) Don't worry guys planning on re-building engine and tranny first before I do any boost things.
20 PSI IS really that much on these engines. If your comparing with japanese makes, think of it like this: those cars generally have smaller displacement engines that run a slightly lower compression ratio and they are high RPM engines. where our cars are lower RPM engines but run higher CR and more displacement. Now pump 20 PSI and fuel into say a 450CC (1.8L engine divided by 4 cyl.) cylinder. now compress that with a 8.5:1 CR, ignite and you get X amount of power. Take 20 PSI and fuel and fill a 600CC (2.4L/4cyl) cylinder and compress it with a 9.5:1 or 10:1 CR, ignite and you get way more than the small cylinder. The 600CC cylinder has a lot more air in it than the 450cc one, that means you can add more fuel and get more power. With more power comes more pressure as the gasses ignite and expand. Its these pressures (among other things) that dictate the strength your internals must be.
This is my understanding of this and if i'm wrong please correct me. Not the best explaination but hopefully someone can understand it
Edited 1 time(s). Last edited Monday, July 14, 2008 9:53 PM
^^You're forgetting their dissplacement, and our lack of aftermarket support for PROPER tuning ability
Honda and toyota (excluding the 2JZ I6 engines in the supra) all have small dissplacement for their 4 cylinders. Which means they essentialy need to play catch up by pushing more boost to get the same results that everyonme else gets with 2.4/2.5L 4 bangers.
Example: take a 1990 DSM whether it be a talon or eclipse. They have a straight 2.0L engine. for them to make 200 horsepower they need to run 11-12 psi of boost.
Whereas our j-body 2.4L (assuming that's you engine of choice) can easly make 230hp with a very cheesy 7psi becuase we start off with the upper hand of have a larger displacement over them, in turn giving us .4 of a litre more exhaust gas velocity to spin the turbo turbine.
that and motor to motor, our larger displacement gives us more power (if they don't a have a turbo on their 4G63 or 420A)
bigger displacement = more power to begin with which equals less boost needed to make big hp numbers.
NOW, as for the tuning aspect! Our platform is all good and dandy up till about a 2 Bar MAP, which we can't even tune for 100% without the help of a stand alone fuel management system (MSII to name one of the many) but we can manage with HPT and the GMSC reflash (which gives us a FAKE 2 Bar tune)
A fake 2 Bar Tune is essentially making the computer think it's running normally, when really it's using more fuel to make up for the massive amounts of air it's taking in. Since our ECU's are pretty much garbage for their OS (Operating System) They can't actually understand boost, which is why we have to "trick" them into thinking they're still running within 1 Bar of a standard MAP sensor.
In doing this, we loose resolution, meaning we can only go so far as to dialing in the perfect amount of fuel to use to accomidate the extra air.
Imagine if you will, an Exccel Spreadsheet that is 13 cells by 17 cells. Thats 221 cells for us to work with for getting the fuel mapping just perfect. It may seem like a lot, but it's not much room at all.
Where as DSM's, Honda's, Toyota's, they all use MAF sensors which tell the computer the EXACT amount of air going into the engine, instead of you needing to guess the values. And with Hondata ( Honda's aftermarket ECU replacement) their "Exccel Spreadsheet" type fuel map grid is, in other words, endless.
That 221 cell grid seems tiny now doesn't it.
If you need more answers read up in the Tuning Forum and also checkout www.4cyltuner.com
