94touring

What would be considered too much boost to run on an engine and turbo. I have a new engine with 2mm seals and the apexi single turbo.

Rx7thHeaven

Lots of people run 20psi on race fuel. Some even run 20psi on the street. Although I am not quite brave enough to run 20psi on pump gas I wouldent be scared to do it on race gas. If you have good fuel delivery and dont tune too lean you will be fine running 20+ lbs of boost.

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1994 Black Touring
R1 front and rear spoilers
T78 single turbo
M2 medium intercooler
Apex power Fc W/commander
HKS dragger catback
HKS super sequintial BOV
Shane Racing radiator
1400 cc sec. injectors
Weldon fuel pump
18" Enkei Rp01's
I have more mods just cant remember all of them sense my sig was lost when the forum crashed

AOL Screen name- Jon52781

AJC13B

To much is when it breaks

94touring

I have all that except the racing seals. I will probably only turn the boost up to 20psi when I take it to the track. I have a trailer for it too which I had planned on using. Using premix isn't a bad idea either, is there an equation to use per gallon of fuel?

pluto

Wow Gordon, Who do you know that rebuilds the motor after each event?? Also, I have been running 24psi w/ n2o on the street for the past 2 months. It is alot more fun to beat up on motorcycle as long as you can afford the race fuel. Also, the comment on the 9-10sec is kind incorrect because if the car is tuned properly, you can run it all day long as long as the water temp stays cool.



[This message has been edited by pluto (edited May 13, 2001).]

94touring

So basically run on the rich side to keep it safe. If I had enough fuel delivery and maybe even ran race fuel, would running over 20psi be harmfull to the engine and turbo?

HWO

guys are running 28psi on stock 2mm apex seals, its all to do with having the right clearance on the apex seals, the springs only play the game when the engine is at low rpm and when it is not running.
if you can source 120octane race gas, and have a turbo which can blow 30+psi, have enough fuel on tap, then by all means go for it, as long as you dont lean out and everything else is right, your engine will handle it, weather your underwear can handle it or not however maybe another story

RICE RACING

Here is my practical advise to you for the street...

I would run no more than 14.5psi or one bar boost on a 9:1 comp engine on pump gas with moderate ignition advance (around 15deg) with a heavy ported engine at wot and high rpm 5k+.

This will be safe for all weather/atmospheric conditions asuming your charge temp (temp just befor intake port) does not exceed 50deg C or 120 F and your water temp is below 92 deg C.

Racing gas (100octane and higher) have different limits and factors associated with them and they vary in performance threshold from supplier to supplier.

Note less "heavy" ported engines can run more boost and more ignition advance in the higher rpm ranges due to less efficient operation and hence less heat (due to less charge in the combustion chamber) load.

RICE

crispeed

[QUOTE]Originally posted by gmonsen:
The guys who run 25-26-ish are doing it on a drag strip for about 9-10 seconds, then they trailer it home and rebuild the motors for the next event.

This is the kind of ignorant advise that a lot of people have been posting on the forum lately! What a bunch of hog wash based on no actual facts or experience.
You wonder why the people with the know hardly post here again!
Stop looking at a few individuals when stating opinions like the one above.Just because they can't figure out the combination to sustain engine life at high boost dosen't mean there are others who have not done so.
Probably you should ask BOOSTED RX7 about his last TII that has been running for just under two years now with no less than 22psi on pump gas on a daily basis that is making over 500rwhp how it's done!

crispeed

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[This message has been edited by crispeed (edited May 14, 2001).]

RICE RACING

Rotary performance, in particular turbo RE performance is a never ending balance of reliablity v's power v's available technology then to this you need to take into account ALL operating conditions...

Any recomendations I make will be with an apropriate saftey margin associated. I think you should if indoubt consult with a local tunner and get him to show you a vehicle either his own or a customers with similar mods to what you have or plan to do, then go down to the local service station, fill up the car and go for a drive....If he has total confidence and is not full of **** he/she will be more than glad to prove what they claim to you. I know I have done this to many potential customers of mine to prove certain systems to them.

Just remember atmospheric conditions have a BIG ******* bearing on the thermal limit of the engine, it may perform fine at WOT for 10seconds on a 20deg C day, but detonate if held for more than 15seconds or repeditive power applications in the same weather condition, or detonate in less time in hot weather conditions....

Anything can be pushed to the limit on a particular day, but one day a bad fuel batch, a hot day, or an extended power run will cause your engine to fail.

Professional tunners engine builders will be more than glad to back up their advice with a practical demonstration if you are fair dinkum about dealing with them, hell if you get one on a good day they will just want to show you what their products can do

Again this is my recomendation for you to cover all circumstances on average 95 to 98 octance "pump" fuel

1 bar boost, or charge temp limit of 50deg C note if you can keep charge temp down then you may be able to run up to 20+psi or 1.4 bar boost, it is very dependant on charge temp!!!

1 bar covers long periods of power application in hot weather with air to air IC.

Anywhere from 15deg advance to 20 deg advance depending on porting and engine temp.

13B power limit of around 600bhp on pump fuel, regardless of the method used to achieve it (more porting-less boost or more boost-less porting), is a safe target for a street engine.

Again hope this stuff helps you, it is just my opinion and I am not saying that other stuff cannot be done...tend to look at things from a circuit racing perspective and like reliable set up's that will have a "big" saftey margin to them.

RICE

crispeed

You know Peter I've said this to a particular person on the forum once before.
When I deliver a daily driven 500hp car to customer it's not meant to be driven for only a few seconds at full output.Some of the guys here based their success on what the dyno says on a single gear run for a few seconds.Let's see them take a run on the highway at 8500rpm in fifth gear and see what the results are.
But then again most of them still havn't figured out how to make 500rwhp at 20 psi or to make power above 7500rpm either!
Water is the sorce of all life

crispeed
Will be MIA again shortly!

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[This message has been edited by crispeed (edited May 14, 2001).]

94touring

Thanks for the advice guys. I will go for as much boost as fuel delivery will allow me to. One more question, how much boost will my 1200cc injectors hold before maxing out? And I assume that the apexi turbo can hold way over 20psi, correct me if I am wrong.

HWO

only run over 20psi if you have high enough octane gas, you cant run that much with much margin for error on pump gas.

Cheuk in Seoul

I believe that the apexi is good to about 1.5 bar or 22-23 psi before it starts to drop off in efficiency.

Cheuk

MikeL

Just FYI:

I sometimes hit 17 psi if I punch it from 45 mph in 3rd gear. I have a T-66 and .96 p-trim turbine housing.

Using 93 pump gas, my J&S will sometimes light up a couple of lights as I approach 8k rpm.

I'm not saying that mine is tuned the best that it can be.

Mike

crispeed

Hey Gordon!
I was just trying to get the facts right based on your above comment.
To me your opinion was just based on the experience of a few individuals out there.
I understand your points about true reliability and max boost levels etc.which happen to be good ones
but you did not have to call names of certain individuals to prove your point.
Remember we are all in this together!

crispeed
Present state:POW



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Cheuk in Seoul

My APEXi (ported engine, midpipe, cat back) will hit 20 psi without problems. I have been hesitant to turn it up any more even with race fuel.

Devilish

For what it's worth, the World Challenge RX-7's (Pettit, M2) ran 20 psi when they were still in the series. Of course, 20 psi was mandated as the maximum by the rules, but the cars held up ok for an hour hardcore race at that boost level. And correct me if I'm wrong (and I might be), but doesn't World Challenge require 93 octane gas? Brian said he would turn it up to 22 if allowed, but reliability did become an issue past that level for sustained racing conditions.

Devilish

Actually G, I know the World Challenge thing for a fact. Just don't ask how. But you're absolutely correct when talking about a street set up. I know when the T04 goes on, I'll probably keep it at 12 psi to be on the safe side.

carcrazy

Are we all talking about street driven cars? Seems as though setting a 1 bar limit is a good mark to follow, especially in light of pump gas. Sometimes that 93 octane will be less. Inlet air temp is a big factor also. The more boost, you get MUCH more heat. This translate into the need for a more effective intercooler.

When you start pushing the limits of:
- inlet heat
- boost (equals more inlet heat)
- gas octane
- timing
It ain't no street car anymore - at least by definition for reliability. This turns into a hobby of big horsepower and blown motors. I guess I tend to leave "the edge" to race cars and my "hobby/race" car. My RX-7 (393 hp) is fast enough for the street and more than enough of a handful on the track. When I can break traction in second gear on one section of the track, I know I have way enough power.
All mods I make after this will be for reliability. So far, the car has been a dream and extremely reliable. I am running 1 bar and mild timing.
It is best to look at the variables and take an engineering approach to extracting reliable horsepower. Changing a parameter of the operation of the motor without looking at the ramifications is begging for a blown motor and money taken from the modifications list. As in the Limp Bizkit song - "Just think about it..."

laterz

Rick
Treat your rotors with respect!!! Your rotors will treat you with respect.
Spinning is just natural!

carcrazy

Interesting after reading all the rest of the thread...

My engine builder (Redline Engineering) said this:

Pump gas - 1 bar max
Race gas - 20 psi max

he said this would be a safe number to run.

He also said that I can spin safely up to 9,000 rpm and to set the redline to that. He said it would spin to 10,000 rpm if I needed. IF I spin the motor to 11,000 rpm, prepare for the motor to grenade. Never hit 11,000 rpm. This is with the mods I have.

Just information for all.

Rick
adding to the melting pot of a thread...

R1DREAD

I think 1bar on the street is a waste.why even bother putting on a single? I think 20psi is perfect. Supras and 300zxs make 600 Rhp on pump gas.what do you do when you're on the highway they run up behind you ?pull to the right? if you're like me, you hit the low boost button 1.5 bar and nail it,

Poweraxel

i know what you mean i run 18-19psi on 93 octane and 23psi on race ras