jgkurz

Diff?

This is a great video. You can hear the car, see the xmas tree and the timing lights. It's better than I usually do. BTW, I think your signature needs to be updated. The 409.56 hp. 391.11 torque is a little modest. To run 131.98mph in the 1/4 mile with your car equates to roughly 500rwhp. .

I never thought I'd say this about a whaletail but it's more subtle and blends with the lines of the car much better. A whaletail on my car would look out of place, on your car it looks like it is suppose to be there. Just my .02C. Your next mod should be a twin turbo LSx.. BTW, is the car stable at higher speeds? I'd be curious to know if there is a difference between the two rear spoliers.

Great write-up Bob. Thanks for taking the time.

John, I need some driver training to help me with these exact problems. For whatever reason I often hit my corner apex's too early. I am getting better at not unsettling the car. Care to come out to Oregon to give me a few pointers? I'm going to try and go to the June HPDE to improve my skills. http://www.cascadesportscarclub.org/training.asp?page=home

But does the dual VanBergen power coupling prevent side fumbling? This has been a noticeable problem when engaging the unilateral phase detractors. Sometimes a new girdle spring will fix the problem if the dingle arm isn't prematurely worn out.

This is hilarious...

Phil, Here's an example of a car that made 400rwhp with far less mods than you or I have. Remember Morgan Fruchtnicht's budget build in the Fall 2002 issue of Sport Z magazine? It's the same issue that featured JeffP's car. http://z31.com/~morgan/oldz/ My point is that you should have all the right parts to get to your goal.... You just need a few more tweaks. I know how frustrating it is to be so close to your goal. Let me know how I can help.

My N42 intake has the throttle body mount extensively ported and the runners are port-matched slightly and blended. The runners don't have much done. My cylinder head has the runners port-matched and my valves are back-cut. That's it really. I honestly think Phil can make big improvements without going through the trouble of going to a custom intake. The stock intake, ported or not, is done at about 5500rpm not 4500rpm. I've seen this over and over on dyno sheets and in different cars. This is just my opinion, but I'd look somewhere besides the intake manifold.

Paul, I agree that the intake is a place to start but I contend that cylinder head work should be done at the same time to net worthwhile benefit. I would love to have a Rusch Motorsports head and a Ron Tyler intake on my car!!!! That would give me huge gains. Without Meth and a near stock N42 intake and P90 head I'm at 455RWHP with crappy AFR's. I have more displacement but not 114hp worth. I think Phil can get to 400RWHP without an intake change. Assuming the turbo is up to the task, I'll bet the problem is in AFR's, ignition and/or possibly boost control at peak power. JeffP in another thread posted today seems to have a similar problem with spark dwell.

Phil, Once you figure out why the power fell off after 4500rpm you'll get to the 400RWHP. Either way it was a great pull. I'm curious why you would want to do a dyno pull in 3rd gear. The power curve is more realistic when the gears are 1:1. You also don't get nearly the traction problem in 4th as you probably learned. Did the dyno operator recommend it?

Jeff, A good friend of mine who owned a local tuner shop told me that he liked using the standard thick electrode (non-platinum) plugs on turbo cars. His shop dyno'd and tuned a great deal of turbo cars so I took his advice seriously. I have had great success with the following plugs depending on the situation. NGK BPR7ES plugs at .030 gap on pump gas at 15-20psi and NGK BR8ES plugs at .030 gap when I'm going all out on the dyno or track. You may need to go to a Yamaha dealer to get the BR8ES plugs. My EFI doesn't allow me to change dwell but I don't have any audible misfires or hesitations under boost that I'm aware of. Good luck.

It's been my experience that the L28 intake and heads just don't make HP much past 5500rpm without significant porting. I've seen this demonstrated on the dyno with my engine other similar setups. TimZ and JeffP both make peak power well past 5500rpm but it took a huge amount of intake and cyl head port work to get there. For me, a larger cam didn't move the power band up either. Peak torque is typically at 4200 - 4500rpm. When doing a dyno pull I believe you should definitely run the rpm's well past peak so you can fully understand the characteristics of the engine through the whole RPM range. Just my .02C.

Cool! Thanks Joel.

I looked at the video last week and it worked fine.

Beautiful car. The suspension is one of the the most modified I've seen on an S30. I do think this statement on the website is a bit optimistic.... "Producing over 400 HP coupled with a race proven chassis this car will be at the front of the grid at any historic IMSA event."

The best I was ever able to do with an L28/N47 head was 15.6@87MPH. I didn't have a header but there were lots of small tweaks done to the car that made it fun to drive.

Scottie, I agree with you but I've always wondered if you speed shifted (kept the gas pedal matted while shifting) if you could mitigate the advantage of an automatic. That method is an old muscle car way and it's HARD on parts but it might gain you a tenth if you can do it right. I've been tempted to try it but I always chicken out.

Hugh, To fit my 3" DP in my S30 I had to create a small channel in the transmission tunnel with a "jaws of life" hydraulic spreader. You may need to do the same.

Just use a larger turbine like .82 or higher and you should be OK. Your compressor looks like it will support decent power but like you implied, it might surge if the boost comes on too quickly.

I went an indicated 142mph in a mildly built 1978 280Z going down hill with the pedal matted for what seemed like an eternity. It was on a stretch of I-5 between Marysville and Mt Vernon WA. Eventually I did this to the car... This was all back in my "not so smart" days...

Hmmmm. Suddenly my email notifications have started working. It must be magic. Thanks Dan.

This is just a guess but maybe SuperDan has turned off some functionality to prepare for the server upgrade?

Is it just me or are any of you having trouble getting email notification of a new post for a subscribed thread?

The SDS calculation would be for brake horsepower aka crank horsepower. On a compressor map it takes about 10lb/min of air for an efficient engine to make 100BHP. The L28 head is not a cross flow or 4V head so we need a bit more, say 11lb/min per 100BHP. So if your engine should make 400BHP you should see about 340RWHP on a chassis dyno. This would be with a 15% drivetrain loss. These are all rough estimates and can change depending on the dyno, temperature, barometric pressure, air density...etc. My compressor has an Innovative GT58 trim wheel with a .50 A/R housing. The turbine is a .63 Nissan with a stage5 ten blade wheel. Below is the map. So far I've made 454.9RWHP with this turbo.