HowlerMonkey

Come on by and say hi at the performance power racing pit area if you go.

I went to "high butterfly" stacks on my 914/6 2.7 euro compression ratio engine with rsr cams and the engine put 255hp to the wheels. It actually seemed to help throttle response with the butterfly's further away from the ports but that engine was a pretty extreme example. The location of the throttle plate has be figured into the "big picture" when you are considering stack length and cam timing.

The hardest part of comparing the P79 to a P90 with flattops is that most who swap the heads will swap the head complete with cam. I've just recently replaced a P90 with flattop long block assembly with a 1983 P79 long block assembly over a days time and notice no difference in performance between the two at stock boost. I'm sure the liners in the p79 don't affect performance until much higher power levels but I fear that extended running at high boost (standing mile....etc) could cause the liners to get hot enough to start to erode and possibly start losing chunks.....which is tough on turbos. I'm not sure how the comparison would go with a non-turbo engine.

Yes P99 I got one off of a very late production date 1983 280zx turbo manual transmission car that had thrown a rod and replaced it when I worked as a tech at lustine nissan. It could have even been a canadian market car since I seem to remember a 280zx turbo manual there around that time that had a french speaking bitching betty. I rebuilt a turbo and swapped head/turbo/manifolds to my 280zx turbo and drove it for 5 years in my 280zx and gave the entire engine with a built 3n71b to datsun dynamics where I used to work along with the original p90 head and manifolds. From there, the trail goes cold but I'm sure someone got that sweet running engine and will eventually show up on a forum somewhere and show pics confirming the casting number. Other than the casting saying P99, it was identical to the P90A.

If you found flattops in the engine, you will most likely find the rods lack the oil squirters that cool the pistons down. Depending on your application, this might be important.

Original poster needs to check if he has P90A or P99 head since he did state a 1983 L28et.

Where's the P-79 vs P-90 discussion?

Somewhere here is a thread from a few months or year ago that had some very sweet looking captured mounts. I seem to remember that they might have been based off of some jeep mounts and possibly red in color but not positive.

If the injector driver is fused, the ecu will light up a "noid" light by providing a continuous ground to the injector ranther than a pulsed ground. 12+ is always on.

I believe only the 83 and 84 first generation maximas had that setup. I think I remember that the maxima swingarm shock mounts were slightly differnt height compared to the 280zx. Mine did and I used 280-zxt axles and a 200sx turbo diff mount to fit a R200. Of course.....the infiniti M30 also has that setup though the diff. flange is a about 5/8 inch longer but you can swap on other R200 flanges.

These cars will run for 5 min on puddled fuel. The stock ecus on 280zx will fuse the injector drivers and continuously hold the injectors open if you jump start the car with the polarity wrong. After this has happened, I've seen more than one dealership mechanic run the car with the fuel pump off and/or injectors disconnected because of the puddling caused by the fused drivers. It can and has happened.....just not sure it has happened here but it could have. Years later, at Blue Streak's ecu rebuilding facility, I ran into my fair share of fused injector drivers on these ecus.

On rotary engines, Weber 48IDA were popular carbs and many racers ported the venturis and throttle plates to 51mm or so. The caveat is that you lose a bit of the "signal strength" that is created by the venturi if you change it's size or countour. Rotary guys already have low rpm response issues that require a rev happy driving style so the lack of signal is just a drop in the bucket on a J-ported, monster ported, or peripheral ported rotary. These are downdraft carbs but the same principles apply when enlarging. If you want to see extremely large ports, you should take off the plastic plenum of a lexus IS350......pretty amazing. You can look down holes that are near 50mm or larger and see about 98% of the valve where it touches the seat.....the runners are that straight.

Original poster has to ask himself why the liner got so hot that it came apart? Does his exhaust have a restriction? Is the timing retarded? Time for an egt probe. I say this because I am also running a f54 with p79 head and, even though the performance seems identical to the p90 head, I am hearing evidence of excessive heat while running low load and 4000rpms. I'm going to swap the rods out for the ones with the oil squirters and see if this changes anything as well as hooking up egr since low load highway driving uses a bit of egr to keep combustion chamber temps down in the stock usage.

Just busy preparing the current world record standing mile holder for the texas mile. Actually.....just seeing how far getting the last word in will continue.

The down side is getting stranded when it fails. This is why toyota had a throttle cable on most of it's drive by wire engines for a few years after they were introduced.......so you could still get 20% throttle if it failed. Straight drive by wire with no other systems affecting throttle would be ok but most every OEM version I have seen spends way too much time interpreting what it thinks you want it to do. Manufacturers have done some strange stuff concerning the actuation as controlled by the ecu such as....... 1. opening the throttle more than the amount you are commanding to make the car feel more powerful that it really is. 2. Closing the throttle during upshifts to save a weak tranny which allows it to get through warranty period. You should watch scope on the throttle body....it will surprise you what really is going on. RE: the toyota thing. There have been no cases that have even made it to court. Toyota is around 12th on the list of "sudden acceleration" complaints based on brand with volvo being number one.

Hey! Where's the 3.4L whipple?

Do those rods have the oil squirters that spray the bottom of the piston?

I was wrong and I sure don't deserve the ad hominem crap spewed in earlier posts on this thread. I as wrong because I forgot to figure in the other "bellcranks" in the stock linkage which change the "curve" and possibly nullify the progressive nature of the geometry concerning the bellcrank at the throttle body. Sure there is an area difference between the 60mm and 50mm throttle bodies at very small openings but the difference is just not enough to cause a huge driveability issues listed by others above since those same "surging" issues exist with the stock 50mm throttle body. The perception of difference between the two is usually a problem since most "upgrades" that include going from 50 to 60mm usually include much more than just the throttle body alone. Compare the difference back to back on the dyno and you find very little at same measured throttle angles. I will get back to this at another date and prove my points with potentiometer tps data corrected to true throttle angle data with two back to back dyno runs (dyno dynamics twin retarder) on a stock L28et with both 50 and 60 but I'm very busy changing upwards of 240 valve springs per week at lexus while finishing the current official standing mile record holding car for october's texas mile competition. Come on by and see us at the Texas Mile on october 16.

I've had good luck from .... http://www.thepartsbin.com/

Stock linkage is not linear. It is impossible for it to be linear through it's near 90 degrees of throttle shaft movement. On the 280zx throttle body linkage, it starts out with the minimum authority and gains authority in relation to the throttle pedal movement the further it is opened.

I've replaced a VG30 with a L28et but it was in an Infiniti M30. runs great.

My experience with both the 60mm and the 50mm showed me that the biggest difference in "tip in" response is the changing from the stock progressive linkage to a linear linkage......or someone modified the stock linkage to the point that the lesser authority at the beginning of the travel has been moved or negated.

So ColdFusion will be Cold Molding with a vacuum bag....or will you use an autoclave?

The stock linkage gives the pedal much less authority at the beginning of the travel and much more authority as the throttle is opened more. I am quite fond of how it works. When using the same articulation of the linkage, I notice no difference in response between the 50 and the 60. Perhaps the people noting too much response at low throttle openings have swapped the stock linkage "throttle curve" with a truly linear cable....which opens the throttle "faster" than the stock linkage at the beginning of the throttle movement. The porsche 944 has a pretty progressive throttle cam and may be a source for a more driver friendly curve. I remembered this because I worked with Al Collins at autothority to make a linear cam for quicker throttle response on the 944 back in 1985.

I've seen two different crank pulley bolt lengths. Just though I'd throw that in.