S8ER95Z

Why is compression even being looked at here? Is this the new Hp per liter argument of the future? The 4.6L is a completely different design than a OHV motor.. which if they were equal then you could say.. the 4.6L should be making equal or more with equal or higher compression. Its not though. In comparison to the 350Z make it SOHC and see what happens.

Also different Bore and stroke are 2 more variables.. oh and the amount of rpms..etc... I have no clue why this is even being discussed as it makes zero sense. When the 3.5L Nissan motor starts cranking out some real HP let me know.. until then.. who cares? The ability to squeeze tons of HP out of the 4.6L already exists.. Im sure your time will come.. until then quit comparing two engines that are far from similar. Maybe Nissan squeezed almost every available ounce of power out already? Ford obviously didn't even come close to getting every ounce out. Which means more power to come in the future without redoing internal components. This reminds me of the AMD Athlon/ Intel wars...

Silver Snake

Wanna run me in my little 281ci. 8.5:1 compression car?

ThreeFiftyZoom

The GT is not DOHC by the way and has 9.4:1 compression starting 2001 and 9.0:1 before that.

S8ER95Z

Guess I can only claim to know a little more than nothing.. hehe.. double checked your right.. (Obviously.. ) DOHC in the Mach1 and SOHC in the GT. I get going so fast searching for things I guess I keep merging info.. what was the big change in 99 then? I thought the 4.6 went from SOHC to DOHC thus the increase in power? Was it a different cam(s) ? - (the're are two..Im aware of that )

JP00SS

I think it was new Heads

2000 SS

Back to the topic of Mustang GT's. Friend of mine raced a Z owner a couple weeks ago. The Z was stock, the stang had gears, h-pipe and catback. Took the Z two car lenths to just under 100 mph. Was it a member here? It was that burnt orange color 350Z and it happened near O'Hare airport.

Any other locals who would like a crack at this Mustang let me know. He is always up for a good street or track race. He runs late 13's.

sukkoi19

Much better heads, and a 3.27 gear.

ThreeFiftyZoom

In 99 the GTs got better heads and the 3.27s. In 2001 they upped the compression to 9.4:1 and I believe started using the Romeo block instead of the Windsor but Im not sure what the main difference between the 2 are.

02silverstanger

LOL... where do you get your weight figures ?? the Base Z is the only one that is slightly lighter...and it has already been discussed and everyone agrees that stock for stock a Z and a GT is a drivers race.

cobra57

Ok, i drive a 1990 5.0 mustang. BHP is 225 but torque.......that happens to be 300. Fastest ive run was a 14.32 and i consistantly loose by 2-2.5 lenghts to my friend's 03 GT with 260hp and 302 torque stock.We both have 5 speed cars, but i also have a BBK cold air intake and new tires. Against a Z, DRIVERS RACE (99-03). When it comes to weight, last time i check the mustang (99-03) was 3265lbs. The mustang is AT MOST 150lbs heavier than the heaviest Z, (not sure but it's probably more like 90lb.) Against a Z, DRIVERS RACE.

02silverstanger

Weights Curb (pounds) According to Nissan Performance Magazine:

Base 3,188
Enth 3,197
Perf 3,217
Track 3,225
Tour 6MT 3247

SpyVO

This is a pretty interesting thread, really! I am not too surprised that a comparison like this comes up, though. The Z seems to be pretty tweaked from the factory which is why it requires premium fuel. This is probably due to higher compression and/or pretty aggressive spark timing. 3.5L n/a isn't a lot to work with, and they've done really well with it!

OTOH, the GT is MADE to run on regular. My brother has an '02 GT, and another friend had a 98 GT. My friend told me about how he went to the dealership because it was running funny. It was BECAUSE he was putting premium fuel in it. And my brother's car ran 14.4s at the track on regular fuel on a really hot summer night. That's not too bad if you ask me.

The reason I make a big thing out of fuel is because my car has a switch in it that allows me to select between premium and regular. It's adjusts boost and timing accordingly, and you would be amazed at the difference it makes (about 2 seconds at the track!). Also, some computers that I can swap into my car have more or less timing depending on the original application. When you swap computers, you have to tinker with the base timing and tune it to run well given the pump gas that's available.

It's not exactly a spec that you can compare by looking in a magazine or by popping your head under the hood, but TIMING is absolutely critical in any performace motor. And the Z's motor, if you ask me, is more of a performance motor because it's got a higher specific output. The GT motor is still a bit closer to being a brute-force type of deal. Most Mustangs are like that. It's amazing the amount that a couple degrees can make, but when you think that you have 6 or 8 cylinders, each moving up and down as fast as they do (50 times/second at ONLY 3000 rpm), there's a lot of work being done and even the smallest things can add up to a greater overall effect. In the end, I think that computer controlled engine management systems don't get NEARLY the credit they deserve as a performance mod.

Ending rant now...

S8ER95Z

I don't see how running premium could have a negative effect. The Mustang obviously has a lower compression ratio.. however running 91 or higher octane shouldn't make any difference.. I don't see how it could impact the performance at all.

I was going to make a comment here until I noticed the boost... what exactly are you running? I must have missed the post with the details of your setup.. Even with S/C or Turbo... I hope you meant 2 tenths and not 2 seconds. Seriously. 2 Seconds is a huge.. As I said above... details of your setup would help


My personal opinion but since ford decided to short changed you guys in the size department (Ford is convinced size doesn't matter apparently ) I would have expected ford to streamline their engine to get the most available out of it. Its almost retarded that tons of grocery getting cars have equal or more HP than the GTs had up until 99..and now even the Maxima, GTP, and Monte Carlo SS have HP within GT ranges.

Oh and about the GT Motor...where is the brute force part hiding at? (just messing with ya.. The Stang vs Camaro thing will never die.. I'm not serious about it though most of my friends drive mustangs.)

ThreeFiftyZoom

My GT runs the same on regular or premium. I cant tell the difference. But when its hot outside it pings at high RPMs when Im using regular so I usually use premium during the summer. 9.4:1 is not that low of a compression ratio. I guess Ford doesnt want us stomping the gas so they say to use regular. Less warranty work for them to do.

Zrated

SpyVO- I'm guessing you have an SVO. I have a friend who has had 3 of them. Those cars are alot of fun, too bad they are becoming so rare.

cobra57

02silverstanger,
thank you very much.

S8ER95Z

Thanks for the input! I'm suprised ford would suggest regular. I know my Camaro says 91 or higher in the manual.. I had 87 in it once (Almost ran out and that was all that was available ) Car ran, smelled, and wouldn't accelerate worth crap. My compression is a little higher than stock ..few points higher..nothing much.. but I couldn't believe how terrible that was. Never again. 91+ or I walk I guess. I think I may go down and get some turbo blue to run thru once... love the smell. hehe. Just way to expensive to run all the time. This thing is my daily driver.

forpointsex

.The mustang is designed to run on 87 octane. There are plenty of newer mustangs that run crappy on anything higher than 87 octane. corral has plenty of cases for the non believers.

I, on the other hand use a timing adjuster and run premium gas. With the advnace timing, i get 25 more miles/tank and lil more HP

SpyVO

Sorry for the late reply, I've been getting ready to move lately.

Here's my thoughts on the cars designed for regular fuel running on premium and having issues. This is my shot in the dark, so take it with a grain of salt...

The time that the cylinder has to make power goes from the time of the spark, to about the time when the piston is at BDC or when the exhaust valve opens (I'm not sure which, but those events happen in the same general time frame so I'll just 'ballpark' it). The way they set up the engine to run on a particular fuel has to do with how long this time period is. They calculate the approximate burn time for the given fuel and coordinate the spark timing with the cam timing (for the exhaust valve). This lets them extract the maximum amount of power from the fuel by firing the spark as early as they can and opening the exhaust valve as late as they can. The longer the mixture is burning in the cylinder, the more work you are extracting from it.

Low octane fuels burn faster than high octane fuels. High octane fuels allow you to set off the spark earlier because since they burn slower, the flame isn't creating the highest pressure in the cylinder until just after TDC, which is what you want to get the most power! Low octane fuels have to be ignited later for their maximum cylinder pressure to occur just after TDC.

If you put the slower burning fuel in the engine calibrated for faster burning fuel, two things happen. First is that the cylinder pressure does not reach it's peak until well AFTER TDC. It has the same effect as retarding the timing, and we all know that doing that kills power in a hurry. The other thing that occurs may not be as significant. If the slower burning fuel is ignited later
as in an engine set for regular fuel, the mixture can still be burning when the exhaust valve opens. This raises exhaust temperatures. That can probably mess with the 02 sensors a bit and confuse the computer some.

Think about nitromethane. VERY high octane. Burns very slowly. The timing on those cars is VERY advanced, and you know the huge flames shooting out the exhaust pipes? That's the mixture still burning.

My car is an 84 Ford Mustang SVO. It's a 2.3 liter turbocharged, intercooled four cylinder with fuel injection. And yes, I meant 2 SECONDS. It's really wierd...

-Mike

S8ER95Z

I guess Im not all that familiar with Ford.. but my 95 LT1 detects the octane..or i should say..automatically adjust timing on the fly.. (Optispark advantage?) So it will automatically curb the advanced timing until the bad fuel or low octane is burnt out..and eventually will return to its advanced timing state. Maybe ford still hasnt caught up in that department?

Oh well.. Nice car..those SVOs are sweet. That 2 seconds thing is weird.. LOL