[Ozer]

Even if we nevermind the fact that the engine is rebuilt, has bigger clearances due to forged pistons which may cause it to burn oil, and needs to be maintained very closely, it is hard to have a car perform well as a daily driver, when you boost it pretty high. High boost means substantial spool time and even if it spools pretty quick, huge power spike when you change your throttle input, which makes it a very nervous car.

A Corvette, as a comparison, could still be a perfect daily driver even with 600whp, since it has 6 liters and you don't need high boost to achieve your power goals. Since just 8 PSI would be sufficient to make 600whp, the power delivery would be very smooth and seamless.

All in all, just like most of the rest of us, I don't think you will find it to be a good DD. You can't make 500+ whp on a mere 2.5lt (or 2.7 liter ) 4-cylinder car, and expect it to be good for daily driving. I have a GT30R .63A/R, which spools very fast, yet is not really the best for daily driving since it pushes 26psi, and the power spikes make the car (and sometimes the passengers inside!) very nervous

Originally Posted by Sinister redlines

Ya I am thinking the same but I want a good dd that is strong but not unmanagable.

[Flycaster]

Originally Posted by Ozer

...since it pushes 26psi...

What? Are you pushing that .63 up to 1.85kg/cm2 now? Holy backpressure, batman.

[Sinister redlines]

Originally Posted by Ozer

Even if we nevermind the fact that the engine is rebuilt, has bigger clearances due to forged pistons which may cause it to burn oil, and needs to be maintained very closely, it is hard to have a car perform well as a daily driver, when you boost it pretty high. High boost means substantial spool time and even if it spools pretty quick, huge power spike when you change your throttle input, which makes it a very nervous car.

A Corvette, as a comparison, could still be a perfect daily driver even with 600whp, since it has 6 liters and you don't need high boost to achieve your power goals. Since just 8 PSI would be sufficient to make 600whp, the power delivery would be very smooth and seamless.

All in all, just like most of the rest of us, I don't think you will find it to be a good DD. You can't make 500+ whp on a mere 2.5lt (or 2.7 liter ) 4-cylinder car, and expect it to be good for daily driving. I have a GT30R .63A/R, which spools very fast, yet is not really the best for daily driving since it pushes 26psi, and the power spikes make the car (and sometimes the passengers inside!) very nervous

Ozer I understand what you are saying, BUT the amount the car will be dependable has alot more to do with the tune and many other factors. The car already has a green and I have driven a few 35r cars. Not to mention I am an old muscle car follower (I grew up in a street rod family) and have driven some nasty v8's.

What I am saying (not to get into a pissing match as I do agree with 99% of what you say) I know the car wont last 100k miles, things will break, and it will be a very nasty car to control. BUT I dont drive hard everyday (I am in my thirties and my last speeding ticket was over ten years ago, now that I have jinxed myself LOL) but when I want to goose it, it better get up and go.
I also want a car that when I get up in the morning to go to work it better start and get me there.

[Ozer]

My bad It is set to 1.75kg/cm2, but it spikes to 1.80kg/cm2. I think my turbo got a bit damaged when its coolant line failed and is now burning a bit of oil, but it still pulls, and I should show you the car and we should compare next time when I stop by Portland! Oh, and you should let me know if you'll stop by Seattle some time.

Originally Posted by Flycaster

What? Are you pushing that .63 up to 1.85kg/cm2 now? Holy backpressure, batman.

[Ozer]

I hope that it will be reliable! My engine is fully rebuilt, too. It has made 25000+ miles now, and it still feels good. I hope it keeps that for another 25+K We don't have much information about how long the built engines may last; fingers crossed!

Besides reliability, I was more concerned with the driveability. The power is linear at most American muscle cars, whereas, in our overboosted cars, the power could probably be defined with a very high-powered polynomial! This high parabolic power curve (especially during the spool) is probably not the best thing for the street

Originally Posted by Sinister redlines

Ozer I understand what you are saying, BUT the amount the car will be dependable has alot more to do with the tune and many other factors. The car already has a green and I have driven a few 35r cars. Not to mention I am an old muscle car follower (I grew up in a street rod family) and have driven some nasty v8's.

What I am saying (not to get into a pissing match as I do agree with 99% of what you say) I know the car wont last 100k miles, things will break, and it will be a very nasty car to control. BUT I dont drive hard everyday (I am in my thirties and my last speeding ticket was over ten years ago, now that I have jinxed myself LOL) but when I want to goose it, it better get up and go.
I also want a car that when I get up in the morning to go to work it better start and get me there.

[Sinister redlines]

Agreed, I am just betting that the extra .21L will help smooth some of that on-off boost and make it more linear. The 35 cars that I have driven are just as you say little power then BAM! big power.

[Flycaster]

Originally Posted by Sinister redlines

...I am just betting that the extra .21L will help smooth some of that on-off boost and make it more linear...

Personally, I don't think an extra 12 cubic inches of displacement is going to do much for that. If anything, it'll make initial spool even a tad quicker, and that's where the "hit" comes from.

IMO, a good tune combined with a good, gear/rpm independant EBC is the only way to accomplish what you want. Most [all?] tuners set boost controller duty cycles to spool as quickly as possible: that's why you see the huge mid-range torque lumps and "quick spool" bragging rights. This rapid power onset is certainly seductive, but it is this torque lump which can turn a DD into a real handful; come out of a corner on a semi-slick street and have your wheel torque double in 800-1000 rpms is simply a recipe for disaster. By using slightly less aggressive duty cycles in the lower to midrange rpm points, it would be very easy to smooth this out. You'll still make the same peak power in the upper rpms, but the ramp up will be far more lineal, not to mention the fact that you'll get the secondary benefit of greatly reducing engine stress at peak Ve.

Also, lost in this discussion is the need to appropriately spring the EWG. The higher the spring pressure, the more PTFB effect you get. This greatly impacts DD drivability.

Bottom line: use the lowest spring pressure you can to still achieve controllable peak boost, and set up the EBC to ramp boost to suit your driving style.

[MartinSTi05]

I have similar reservations with my current build. I am putting a full race twin scroll 3076R on a 2.7L Axxis/crower block. Aforementioned details along with coated/wrapped headers and coated Comb chambers, pistons, and Exhaust valves should make for entertaining spool characteristics...

[wayno]

im looking at buying that same set up with the bc 2.7L and race rods with the gt 35r have you done the build yet and whats the numbers? keep me posted!! where did you buy the bc kit? and how much?

[Valetudospang]

Wow im looking at doin this also! full race 30r 2.7 block! Please Please post how much this is costin ya, cause i would really help me out! or just send me a pm!

Drew

[twigg107]

Wow.... this is an old thread! The last time I was at sinister's place, the block has been done for awhile but he hasnt had the time to put it in.

[slowmike]

Originally Posted by Sinister redlines

Here is one of the heads that we ported, polished and equalized on the flowbench.

Do you have a pic of the exhaust side? I'm curious to find out what to do to the "dog leg" exhaust port to get better flow.