jimbo1111

For God's sakes its got a solid lifter head

So does a e30 m3.

Duke

I don't think evil was too serious, there are several high performance production cars that uses solid lifters.

evil 944t

I was kinda serious, whats your guys point? Mine is that he converted it. Anyone whos very serious in raising the rpms for racing will do that mod.

I could care less if its stock on a Ferarri, BMW etc.. we are not comparing other cars here, are we?

sweanders

Evil, would you then say that an engine that has internal modification is not a street car engine?

evil 944t

sure, why not. just my opinion..

I think we all have too many ideas on what each of us consider street or track so.. this will never end

M758

The difference between a street car engine and a race car engine is vast.

Interesting it is in many ways easier to make an engine in a street driven car more powerfull than in a race car.

Why? Reliabilty. For a street car you can a simple glory run and crank up the boost and make big hp.

For a race car a glory run is useless as you need to make power on the track time after time. Ok maybe turn up the boost for 2-3 qualfying laps, but you still need to race the thing.

All you need for a "street car" is to turn up the boost get one 600 hp run.. wipe your brow happy that it did not blow up, turn down the boost and drive away in your "600 hp" car.

Of course a race car does have a number of advantages in making power that a street car does not. Thinks like idle and low rpm performance are not an issue. So you can go with radical cams, etc.

Interestingly it seems that for NA engine "proper race motors" can make much more hp than "street engines" due to thinks like super high compression, cams, etc.

However Turbo cars seem the opposite. It is very "easy" to make huge street hp simply by dumping in race gas & cranking the boost for a couple dyno runs. Heck even the right turbo can do it by making big peak numbers.

Turbo race motors seem in general to make less hp because they need to make the motor last at full boost wear as a street car guy can run around at 1/2 boost all day and that same motor will hold together.

Of course some turbo race motors can make HUGE hp.

Example... Early 80's BMW F1 motor. 1.5L 4cylinder (reported to be an E30 M3 type block) was pumping out over 1400 hp. Some say they don't know how much hp the car had in qualfying trim as 1400 is where the dyno stopped.

Now what is a street car motor?

Well to be fair it is this...

Engine is run in a car run on the street legal in your local. Really that means if you must pass emissions then the car is legal at the time of testing. When I mean legal I mean legal per tail pipe emissions (ie cat installed if needed). Not the visual crap. (Yes some folks don't have testing so they get a bonus).

The car must be capable of running on the roads in normal traffic, stop and go traffic, summer and winter. (No snow though). Pump gas from any location not just your special shop.

Now for the dyno run you can put in race gas, but cannot change the tune of the engine. So if you run 22 psi on the street on pump gas you can run race gas with 22 psi, but not turn it up to 25 or anything. Why? well really if the cars tuned for 22 psi street gas then adding race gas won't get you any hp, but will prevent detonation if the pump gas is a bit weak that day.

This is then your real number.


What is race motor? It is one that is used for racing and or on track performance. Two dyno runs are allow. One in "qualfying trim" and another in "race trim".

Now there needs to be a 3rd catagory... That of the glory run. Turn up the boost and see how much it will make. In my mind a glory run is the type were you only run the car in this config on the dyno. As soon as you leave you tune it back to normal.

special tool

Dude - when you say things like this...

"Why? Reliabilty. For a street car you can a simple glory run and crank up the boost and make big hp. "

Its not only wrong, its offensive.
I'll give you the benefit of the doubt and assume you don't mean to be offensive, but I can't let you get away with posting misinformation.
It takes a lot of work to get big power. No matter what the engine type.
If you "turn up the boost" on an engine with improper tuning, or grossly mis-matched turbo, you will blow up, or at best MAKE NO POWER.
THIS IS ELEMENTARY INFORMATION.
YOU CANNOT JUST TURN UP THE BOOST AND MAKE BIG POWER.

This thinking comes from guys with little turbo tuning experience (like journalists). Real life is not like this.

porshhhh951

completely agree.

so what are we debating here? lol.

I think if you have mods that require race fuel all the times its deffenetetly a track car.

and duke my comment was I have yet to see a street 951(a 951 driven on the street by a lister here or anywhere that made that kind of power)

the only time I have ever seen that sort of power was out of a track dedicated car. That was my comment and point.

I was just making the statement no one has done this in a real street car yet...heck only a handful of 951's have prolly made that kind of hp. My comment was just that and nothing else. So theres the difference.

Someone posted up that it had already been done like it wasent a big deal. and I beg to differ it is a big deal and I challenged him to find a 951 that did make that kind of power and turns out he is talking about a 3.4ltr custom motor that makes 600rwhp...well geez sure if thats the case.

I was reffering to our 2.5ltr and 3.0ltr cars.

Duke my comment was no one has done this yet....and they havent.
As far as everything else I guess everyone agree's. it dont really matter what makes what with what. Some people get upset when you quote race gas #'s but, as long as you arent trying to pass that off as pump gas #'s then I dont see a problem with it....we all know the car wont make the same power on pump gas that it will on race fuel.

M758

I am not saying you did a glory run for your hp numbers. What I am saying is that is a street simple does not see the stresses a race motor does.

Even on my 951 90% of its street driving is at 1/2 boost. So the occasional high boost street run is rather rare. For a race motor you run full throttle full boost alot so a 500 hp street motor will be different from a 500 hp race motor.

Now if some one was daring or temping fate I'd bet you could take very well design 500 hp street motor and tweak a few things to get more peak hp to show great numbers and then dial it back so that you don't break anything on the street. Please don't think that I assume your numbers are like that. Nope it seems very much like your 533 hp run was done with the motor in normal trim not a special dyno tune.

Now where do I get my information?

Well locally here in Arizona we had a guy with Technodyne built street car 2.5L motor with 400 + rwhp. How much hp always depended on boost. I think he could get to 450 with max boost, but too many max boost runs would result in heat soak and after 3-5 runs the air intake temps would rise to the point were even race gas detonation was likely. Thise were "glory" runs. Backing off the boost 2 psi put the turbo back in to the proper efficiency range and kept the air intake temps stable and ok.

Of course that was for 100% race gas setting. So he had another one for 50/50 mix with less hp. So bottom line is power varried with tune and normal street tune was different than peak dyno hp tune. Even so the car was very powerful.

Now he considered racing the car, but Chris Cervelli who built the motor told him to race the car he would need alot more work done to the motor to make it last under racing conditions. Remember at the time Chris was racing his own 944 Turbo which was one of the fastest in the counrty at the time so he knew all about the issues of racing a high boost 951 motor.

sweanders

Don't confuse US suburbia street driving with European highway travelling. Anyone who claims that a street car does not need to has as good reliability as a race car is incorrect.

Several times a year I drive on highway stretches with average speeds well over 200 km/h, sometimes I have spent full tanks at over 240 km/h. A colleague of mine and I used to joke about that in some countries you can make up lost time by speeding a bit but when driving to our German clients it was impossible since we were already going as fast as the cars would let us.

Yesterday I drove over 500 miles in the rain cruising at 150-160 km/h (90-100 mph) and was still being passed, that is wintertime driving in Denmark for you. Summertime the cars really get pushed.

sweanders

Seems like if this guy did not have the proper turbo if he had such problems with backpressure.

Are you saying that the stock 951 used in the turbo Cup cars was not good enough for a race car? Same cars that were travelling at 304 km/h in the French turbo Cup series?

M758

Turbo Cup cars were not pumping out 400 whp for one thing.

Secondly there is a difference between a factory engineered street car at 250 bhp and home built street car at 400 bhp.

When talking about street cars I am talking about US versions of street cars. In europe things are different. You can't compare a "street tuned" euro car to "street tuned US car". Lets face it a stock 951 S at 80 mph, which is already speeding in every US state runs at vacuum still. This means there is still manifold vacuum pressure less than atmosphere. Maybe when you find a hill you run up to 1 bar on stock gauge. This means you are AT atmospheric pressure. Still no real boost yet athough the turbo is pumping air.

My point is to use 600, 500, 400, hell even 300 hp on the roads in the US is rare. Maybe 1 mile out of every 1000 for a "performance driver" and maybe 1 mile out of 100 for "racer" type. Point is with that kind of load an aftermarketed tuned motor typically won't see max power very often and this does not need to stand up to the stresses.

When I drive my stock 951 S it sees full throttle maybe once every 2000 miles. Even with 250 hp it has plenty to drive around on the roads and be fun. My friend with the 400 hp 951 found it a waste and sold the car. Sure it was fun to "beat" a 996 TT, but it got old really fast. He never really needed the extra 150 hp the car had and on the track had more fun in his 132 rwhp 944 spec car.

My main point is this there are 400 hp street motors and 400 hp race motors. These are NOT the same thing. I'd venture to guess that most of the big hp turbo motors (be them 951, Supra, WRX, Evo, etc) are street only motors or dyno queen motors. Few are tuned properly or well enough to survive on track for any period of time. Now the 951 probably has a higher percentage of "race tuned" motors vs the "street motors", but there are some out there like that.

I know there are some guys looking to best ST's 533 hp number. These guys won't care if the that motor is a dyno queen just so long as it beats 533 they "win". Now from what I know ST's motor is a real motor but if all you want is to have a dyno show a big peak number...

RolexNJ

If I may interject here. I'm going to have to respectfully disagree with that first part. Why is a 400 hp street vs race motor different? Because one is under load more often and longer, due to race conditions? Well, there quite a few people on here and who I personally know that are "constantly" running high boost (20 PSI+), and for years. I believe that if your car has the optimal mods, and is perfectly tuned, the engine will last a very long time. I agree though that there aren't alot of them that are tuned properly, but they are some no doubt.

Case in point is ST's car. He has had, if I'm not mistaken, a stock bottom end alone on his car for 4 years; and has been running very high boost and has tracked his car several times. So you think that ST's car is tuned just to get that "glory-run" sheet, and can't last under race conditions? Not the case my friend. I disagree with that statement totally. ST is constantly pushing, and pushing what his car can do with each mod. And yeah, to quantify those results he does do that dyno run to see the gains. At the same time, this car has been around the block. He just doesn't do a mod, do a pull, get his "glory run" chart, and never or barely drive it. That's so not the case. If need be, he could elaborate more on this if he likes.

Two, yes there are people who want to beat ST's number, me being one of them. But do I want to just have that "glory-run" sheet, and not have a reliable car? No way! I'm not sure I want to ever push my car to the absoulute ragged edge; but I want the maxium HP out of it with the least minimum risk of damage. So while I personally strive to see what the max HP I can get out of my car, I do want it to last. Also it is street legal, with a NJ emissions inspection, plates, and insurance. And I will bet you that once it is "optimally" tuned right, I could take that same engine, put in a race chasis and it would be highly competitive. And here's the best part, it would last...

That's my two cents.

M758

Well you mis read my post. I never said ST motor was dyno queen motor or his 533 run was glory run. In fact I tried to say that it was not.

I do have to say however that runnin 20 psi on the street is not like running 20 psi on the track. Really how OFTEN do you hit 20 PSI of boost on the street in the united States. We don't drive flat out at 150+ for hrs on end so when other than the occasional 5 second burst do you even get to 20 psi of boost on the street? Really 5 seconds at full boost and you are going way the hell too fast.

On the track you run full boost for for at least 25% of a lap on most tracks if not more. Consider running full boost for 30 seconds every 2 minutes for 25 minutes at a time. That is much more stress than street driving. Even so what are 4-5 track day over 4 years. When you race you run car the hard all the time every time. This means in 500 miles you are probably at full throttle 300 of those miles with little time inbetween too cool things down. The biggest problem with turbo cars is the heat the turbo generates. This heat impactes everything. Then of course all the loads the rods and crank take at 5000+ rpm. Conisder a 400 hp 4cylinder motor. Each piston and rod is taking up about 100 hp. Stock these parts were taking 55 to 60 hp. That is alot of extra load to take. Track time is hard on a cars especially modified ones.

Now on a street car if you take 500 mile drive how much of that time is north of 5000 RPM and pumping out that 100 hp per cylinder? Even if you run 25 psi and have 600 hp you are only using maybe 70 hp of that during an 80 mph cruise. Light duty indeed.

Let me get this straight. I do not mean to sat your motor or ST's motors are "ready to blow up" any time soon. No I think you guys are working on putting together strong motors. However a high boost race motor faces many many times more stress than a high boost street motor driven in the US. If you race a car with 450 hp worth of bolt ons hard expect some stuff to fail. If you do 2-3 DE's a year and are "easy" on the car it should be fine, but beat the stuffing out of it like any racer wanting to win will and you will see problems. These of couse can be fixed, but typically don't happen on race cars.

Just one example is oil temps. For a street car with 500 hp the stock oil cooler will probalby be fine. Most street driving will not heat the oil that much. One or two full power blasts will heat the oil, but 10 min of street driving or idle and it is back to normal. However run on the track and temps will climb since there is no time for the oil to cool. Of course a big oil cooling system won't add any hp and for the street is overkill, but definatly required for big hp race car.

jimbo1111

There is more stress on the motor during a dyno run than on the street. Just from the standpoint of no air cooling the motor and intercooler down. At 80+ mph your getting serious airflow. Heat is the enemy.