Guest Anonymous Posted February 20, 2002 Share Posted February 20, 2002 whats the benefits for lightweight forged rods on a stroker turbo motor (p90, f54, ld28, l24 rods) i want to race prep my l24 rods or should i spring for the sanez forged rods? already got the pistons (JE 8.2:1 with nickle coatings) are they that much better than a prepped l24 rod? looking for a 500rwhp motor? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 20, 2002 Share Posted February 20, 2002 I have a stroker turbo NOS motor i opted fot the aftermarket forged rod because i figured that i would be crying if i threw an L-24 rod out the side of the block.i bought cunningham rods and now i rest easy knowing that my 1000 dollars was well spent.Don`t get me wrong, i am a fan of the stock L-24 rod i just don`t want it in my 400 rwh motor.i have this thing about overbuilding stuff i generally has worked pretty well. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 20, 2002 Share Posted February 20, 2002 Carillo. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted February 20, 2002 Share Posted February 20, 2002 Here is the skinny. I will start by saying I wish I had gotten forged rods. However, the stock l24 rods will handle up to 600hp if raceprepped. I have gotten this information from several sources that include Nissan Motorsports and Mr. Potter. It is not the ideal choice, but they should survive. It is also good to note, the application for surviving at 600hp was road racing which takes much more abuse than a street car. You can get a set of Carillo for as little as $750/6. I still kick myself for not doing so, but I am confident I will have no problems. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 20, 2002 Share Posted February 20, 2002 The issue with the rods is not the rod breaking, but the big end staying round. Sunbelt has given me explicit instructions to pull the rods every 50 hours and measure the roundness of the big end (and these are forged Carillos.) If they are out by .001 or more then I have to replace them. Rod bearings get replaced every 25 hours. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted February 20, 2002 Share Posted February 20, 2002 I have yet to make crazy horses, but hope to soon. We figured 365@wheels with my old-old setup(60-1) turbo based on 12.2@121. My last setup was using a T64 turbo and the same 19psi and it only dynoed 311@wheels, but the dyno would only give a reading after 5800rpm. I don't know what it made below 5800rpm, but do know we had to have 2 people sit on the back to keep from spinning the tires. Anyway, enough with my pathetic excuses. Let us look at what TimZ is doing. His short block has been together for many years now using Cunningham Rods and has always ranged in power from 375-431@wheels with Torque always ranging from 380-472ft-lbs@wheels. He is not having any problems. I also had Sunbelt build my motor which they messed up. I will not go into that right now, but it was the reason my car made no power above 5800rpm. They did fix it, but I paid for new rocker arms and it took them over 3months to return it to me after he admitted it was his fault. Anyway, this is all off subject. I do not think a properly setup motor should be replacing bearings and checking bigend bore, especially on lower hp N/A applications. Flattened bearings will occur if you detonate on the motor and run a constand ping. I have seen it 1st hand on my old-old motor. Let me give you some practical experience I have seen with Carillo rods. My buddies Honda has about 200 dyno runs and about 30 track passes and his car makes in excess of 500hp@wheels, 554 to be exact. He also uses Carillo rods with no problems. Man, can I ramble or what? I don't think for a street/strip application you should concern yourself with such things. Hell, Supra guys are making 600-800RWHP all day long and don't have these issues. Just tune it right and you will be fine. Quote Link to comment Share on other sites More sharing options...
Bob_H Posted February 20, 2002 Share Posted February 20, 2002 A few points. James you are likely right, but realize low N/A hp does not really apply to John's setup. He will likley be pushing over 300 hp and working up towards 8k rpm. It is the 8k and stroker crank that dictates his lower tolerance for error in the rods. And 8k in a Honda motor puts different acceleration loads on the rod than the stroker he has. But as you pointed out, most people with high hp L6 motors are using preped stock rods and experiencing no problems. I agree with you James - Chase, you should have no problems with a properly preped set of 240 rods. Besides, I doubt with a turbo you will be spending much time over 7k anyways. To much good power is made lower. -Bob Hanvey Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 20, 2002 Share Posted February 20, 2002 ok ok, i have another question, lets say i wanted to turn 8500rpm? what im trying to say is what makes the stroker crank better for the turbo application. i know we got a huge and long crank as it is. is turning such high rpm not as safe if you can make just as much if not more power with a stroked motor in the lower rpm range. am i making sense? tim's car is making such torque to match his rwhp. is that desirable? or will i have traction problems at the strip? WHAT MAKES THE STROKER SO MUCH BETTER? hehe you guys rock! digital camera is coming next week i'll show you guys pics of the car and stuff. Quote Link to comment Share on other sites More sharing options...
TimZ Posted February 21, 2002 Share Posted February 21, 2002 Originally posted by Havok:ok ok, i have another question, lets say i wanted to turn 8500rpm? what im trying to say is what makes the stroker crank better for the turbo application. Well, it looks like everybody has already gone over my setup, so I won't bore you with that... One thing to note - my engine is NOT a stroker - it's a plain old L28, with Cunningham rods and Arias pistons. I'm not really convinced that for a turbo application the stroker crank makes that much difference - the displacement is only about 10% larger - this can be made up with about 1.5 psi of boost. As was already noted, John's motor makes it's power at relatively high rpm, and since it's intended to be a track car , will probably expect to see a pretty large percentage of that 50 hours at 6000rpm or higher. The inertial loads imposed by sustained high rpm operation is what is mandating John's service requirements, not the power level. With a turbo setup, you generally make your power at significantly lower rpm (my hp peak is at ~5200rpm, torque at ~4200), which is less stressful on the rods. As far as trying to turn 8500rpm with a turbo, my guess is that you'd be pretty hard pressed to find a cam grind that would allow you to make significant power at that rpm - turbo engines don't generally like alot of valve overlap, due to the reversion caused by the high exhaust manifold pressures that the turbo creates. If you found a turbo with low enough backpressure, it probably wouldn't spool until 5000 rpm or higher. Finally, if you are having traction problems at low speeds, you should also consider that maybe your gearing is not matched to your engine. Shorter (higher numerical) gearing is not always better or faster for a given setup. If you have lots of low end torque, you might be better served by a taller gear ratio, especially if you don't have particularly large tires. Quote Link to comment Share on other sites More sharing options...
Bob_H Posted February 21, 2002 Share Posted February 21, 2002 Actually Tim, I haven't gone over your setup! But to answer your question Chase -first, you really don't want 8500 rpm. There is a reason you don't see any race L6 motors turning much over high 7k rpms. Once you start to go above 8k rpm in an L6, with its long crank, strange harmonics start to take over, reducing power. And as Tim pointed out, the turbo produces its peak power much lower in the rev range - which is easier on rotating parts. If you are going the turbo route, I would stick with the L28, no stroking. There is a lot involved in doing it correctly, (see my site), and to turbo it as well.....you are looking at big $$$$. Just proper tuning and turning up the boost will more than make up for the little bit of extra power the stroker can provide. But you asked what makes it better? Leverage. The longer stroke means the piston will exert a similar force on a longer arm, meaning more turning power, or torque. Granted, that is grossly over-simplified, but it will sufice. Stick with proven combos and you will be happy, i.e. a L28 with a turbo and good tuning. You can get your 400 rwhp with low rpm and without stroking. -Bob Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 21, 2002 Share Posted February 21, 2002 Bobby your site rocks! i've been to it several times so informative. just wanted to give you reconigiton for it. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 21, 2002 Share Posted February 21, 2002 replace rod bearings every 25 hours!!! AHHH! i want my z to be a 500hp car that isnt a total nightmare to keep maintained. maybe i should tone down my expectations. Tod Kenako makes 500hp and i dont think he changes rod bearings every 25 hours. well i hope not. James you make crazy horses with your old motor. What kinda maintaince where you doing? Quote Link to comment Share on other sites More sharing options...
johnc Posted February 21, 2002 Share Posted February 21, 2002 FYI... the 25 hour for bearings and 50 for rods are inspection points, not a required replacement. But, I figured since I'll have the rod caps off I might as well replace the bearings unless they are looking brand new. Regarding how long it takes Sunbelt to deliver... 9 months and counting for my motor. Its frustrating as hell and I've had to miss a couple events this year so I have no chance for a championship. But, Keith Thomas and Chet Whittle have waited as long as 2 years for a Don Potter motor so I guess I'm lucky???? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 22, 2002 Share Posted February 22, 2002 what kinda change is potter or sunbelt demanding for a full blueprint and balance???? im extremely considering sending my motor out of state for building. now that i have to do the stroker. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 22, 2002 Share Posted February 22, 2002 Unfortunately, I think health problems are keeping Don Potter from building any more motors. That's a shame. You can talk with Jim Thompson or Lee at Sunbelt: (770) 932-0160 but just be aware that their factory racing engine contracts (Mazda and Nissan) tend to take priority. Sunbelt doesn't have any set prices, you'll have to talk with them about what you want because there are differnt kinds of "blueprinting" and "balancing." For example: the Nissan diesel crank in my motor weighs 38 lbs - that's 10 lbs less then a stock Nissan L6 crank. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 22, 2002 Share Posted February 22, 2002 oh golly, when there isnt a set price you know its gunna cost an arm and a leg. sigh Quote Link to comment Share on other sites More sharing options...
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