VQ38/VQ40 strokers...
11-24-2005, 07:30 PM
#21
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I don't know if I'm allowed to advertise here... 
So, I won't.. But, just to show you guys what I'm capable of.. here's a few pics of my work..
400whp SR20DET (built motor, cams, SC61 turbocharger)
661whp SR20DET (30psi and 80 shot of nitrous) STOCK intake manifold and log manifold! Built motor, cams, standalone, T61/P-trim..
Built SR20DET, 4-1 custom stainless turbo manifold, custom short runner intake manifold.. (438whp @ 17psi on pump gas!)
World's first destroked QR25DE (Spec V) using SR20 crankshaft, custom pistons/rods, cams and valvesprings, short runner intake manifold, custom 4-1 stainless turbo manifold, custom flywheel and clutch.. made 400whp at 13.8psi on pump gas, revving to 8700rpm so far.. Looking to make 600whp on C16..
I might put a stroker kit together, and assemble engines for people.. I'll have to check to the owner about advertising here before I could do something like that.. I'm going to do some testing for a few months on my shop car, before I would even think about offering this.. Just a thought... we'll see how it works out..
Travis
So, I won't.. But, just to show you guys what I'm capable of.. here's a few pics of my work..400whp SR20DET (built motor, cams, SC61 turbocharger)
661whp SR20DET (30psi and 80 shot of nitrous) STOCK intake manifold and log manifold! Built motor, cams, standalone, T61/P-trim..
Built SR20DET, 4-1 custom stainless turbo manifold, custom short runner intake manifold.. (438whp @ 17psi on pump gas!)
World's first destroked QR25DE (Spec V) using SR20 crankshaft, custom pistons/rods, cams and valvesprings, short runner intake manifold, custom 4-1 stainless turbo manifold, custom flywheel and clutch.. made 400whp at 13.8psi on pump gas, revving to 8700rpm so far.. Looking to make 600whp on C16..
I might put a stroker kit together, and assemble engines for people.. I'll have to check to the owner about advertising here before I could do something like that.. I'm going to do some testing for a few months on my shop car, before I would even think about offering this.. Just a thought... we'll see how it works out..
Travis
11-25-2005, 03:08 AM
#23
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Originally Posted by Trav4011
I might put a stroker kit together, and assemble engines for people.. I'll have to check to the owner about advertising here before I could do something like that.. I'm going to do some testing for a few months on my shop car, before I would even think about offering this.. Just a thought... we'll see how it works out..
Travis
If would be really cool if you make it an almost turn-key affair such as offering a TS ECU reflash to work with the larger displacement.
A cam & Nismo VDC adjuster options are also a good idea.
Last edited by FritzMan; 11-25-2005 at 03:10 AM.
11-25-2005, 04:37 AM
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Sorry travis. This will not work. We found this out the hard way. 
We ordered up a VQ40 crankshaft and test fit it to the VQ35 motor. The main bearings on the VQ40 are 74+MM. The main bearings on the VW30 and 35 are too samll. I think the 35 was 55mm. 
The data below is provided through AllData (a software package for builders like us). AllData basically catalogs and databases all the factory OEM information.
VQ30 Main Bearing Diameter
Pin Journal Diameter "Dp" Grade No.0 44.968 - 44.974 mm
Grade No.1 44.962 - 44.968 mm
Grade No.2 44.956 - 44.962 mm
VQ40 Main Bearing Diameter
Measure the inner diameter of main bearing housing with bore gauge. Standard : 74.993 - 75.017 mm
We ordered up a VQ40 crankshaft and test fit it to the VQ35 motor. The main bearings on the VQ40 are 74+MM. The main bearings on the VW30 and 35 are too samll. I think the 35 was 55mm. The data below is provided through AllData (a software package for builders like us). AllData basically catalogs and databases all the factory OEM information. VQ30 Main Bearing Diameter
Pin Journal Diameter "Dp" Grade No.0 44.968 - 44.974 mm
Grade No.1 44.962 - 44.968 mm
Grade No.2 44.956 - 44.962 mm
VQ40 Main Bearing Diameter
Measure the inner diameter of main bearing housing with bore gauge. Standard : 74.993 - 75.017 mm
11-25-2005, 05:37 AM
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Trav4011,
I ran the numbers not too long ago for using a VQ40 crank in the VQ35 and what I came up just wouldn't work.
First as you stated, the main journals would have to ground down. So much in fact, that over time cracks may develop around the webs thus leading to crank failure.
Second, the stroke is just to much for the VQ35. The rod big ends will not clear the pan rails nor the bottom of the cylinder bores. Also the piston skirts will contact the counterbalances at BDC. For example, increasing the stock VQ35 crank throw by +3mm, effectively increasing the total stroke +6mm, would require grinding of the pan rails by about .125 to avoid contact with the rod big end. The 40s crank throw is 46mm while the 35s is 40.5mm. That's an increase of +6mm in throw and +12mm total stroke. That's WAY too much for this block. So you see, if you have to grind about an 1/8" just from increasing the throw by +3mm, you'll end up grinding almost through the pan rails if you increased throw by +6mm.
Another problem you'll run into is with the piston comp. height. I could not find a rod length suitable enough to keep the compression height of the piston within 25mm. Arias, JE, etc. don't like to manufacture custom pistons with comp heights any lower than 25mm. They will do it if you request it, but the ring packs would be so tight that every last land would eventually fail at the slightest sign of detonation. F/I, forget about it!! Also, with the comp height any lower than 25mm, the pin will interfere with the oil rings and you'll have to use buttons.
There are other ways of stroking our motors using the stock crank, which coupled with grinding would be considerably cheaper than purchasing a 40 crank and having to do all the grinding to it.
Check out this thread where you can pull 3.8 from grinding our cranks and if you decide to sleeve and over bore to 100mm can pull 4.0 out of this motor.
https://my350z.com/forum/showthread....highlight=3.8l
I ran the numbers not too long ago for using a VQ40 crank in the VQ35 and what I came up just wouldn't work.
First as you stated, the main journals would have to ground down. So much in fact, that over time cracks may develop around the webs thus leading to crank failure.
Second, the stroke is just to much for the VQ35. The rod big ends will not clear the pan rails nor the bottom of the cylinder bores. Also the piston skirts will contact the counterbalances at BDC. For example, increasing the stock VQ35 crank throw by +3mm, effectively increasing the total stroke +6mm, would require grinding of the pan rails by about .125 to avoid contact with the rod big end. The 40s crank throw is 46mm while the 35s is 40.5mm. That's an increase of +6mm in throw and +12mm total stroke. That's WAY too much for this block. So you see, if you have to grind about an 1/8" just from increasing the throw by +3mm, you'll end up grinding almost through the pan rails if you increased throw by +6mm.
Another problem you'll run into is with the piston comp. height. I could not find a rod length suitable enough to keep the compression height of the piston within 25mm. Arias, JE, etc. don't like to manufacture custom pistons with comp heights any lower than 25mm. They will do it if you request it, but the ring packs would be so tight that every last land would eventually fail at the slightest sign of detonation. F/I, forget about it!! Also, with the comp height any lower than 25mm, the pin will interfere with the oil rings and you'll have to use buttons.
There are other ways of stroking our motors using the stock crank, which coupled with grinding would be considerably cheaper than purchasing a 40 crank and having to do all the grinding to it.
Check out this thread where you can pull 3.8 from grinding our cranks and if you decide to sleeve and over bore to 100mm can pull 4.0 out of this motor.
https://my350z.com/forum/showthread....highlight=3.8l
11-25-2005, 05:49 AM
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Originally Posted by atlsupdawg#2
Another problem you'll run into is with the piston comp. height. I could not find a rod length suitable enough to keep the compression height of the piston within 25mm. Arias, JE, etc. don't like to manufacture custom pistons with comp heights any lower than 25mm. They will do it if you request it, but the ring packs would be so tight that every last land would eventually fail at the slightest sign of detonation. F/I, forget about it!! Also, with the comp height any lower than 25mm, the pin will interfere with the oil rings and you'll have to use buttons.
11-25-2005, 06:56 AM
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Originally Posted by g356gear
He did mention that he was using custom pistons with a different wrist pin location to aleviate some of the issues you mentioned.
Last edited by atlsupdawg#2; 11-25-2005 at 07:00 AM.
11-25-2005, 07:46 AM
#28
Originally Posted by Trav4011
Yeah... I've read about the stock rods failing.. I wonder if it's the bolts letting go.. or the rods themselves? So, for a N/A motor.. the lightweight stock rods would be optimal.. but, I wouldn't spray too much on top of that.
Travis
Travis
11-25-2005, 09:18 AM
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Originally Posted by Trav4011
Thanks man.. 
It's nice to finaly get somewhere... You know what I mean..
Travis
It's nice to finaly get somewhere... You know what I mean.. Travis
This guy deffinately has the drive and comitment to get something done.
Travis, hows your shop doing? Havn't been on B15 for a little over a year now, so I lost touch with most every one. Definately keep us up to date. Verry interested in the results, looking for a good reliable stroker.
Mike
11-25-2005, 10:57 AM
#31
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Originally Posted by atlsupdawg#2
Trav4011,
I ran the numbers not too long ago for using a VQ40 crank in the VQ35 and what I came up just wouldn't work.
First as you stated, the main journals would have to ground down. So much in fact, that over time cracks may develop around the webs thus leading to crank failure.
Second, the stroke is just to much for the VQ35. The rod big ends will not clear the pan rails nor the bottom of the cylinder bores. Also the piston skirts will contact the counterbalances at BDC. For example, increasing the stock VQ35 crank throw by +3mm, effectively increasing the total stroke +6mm, would require grinding of the pan rails by about .125 to avoid contact with the rod big end. The 40s crank throw is 46mm while the 35s is 40.5mm. That's an increase of +6mm in throw and +12mm total stroke. That's WAY too much for this block. So you see, if you have to grind about an 1/8" just from increasing the throw by +3mm, you'll end up grinding almost through the pan rails if you increased throw by +6mm.
Another problem you'll run into is with the piston comp. height. I could not find a rod length suitable enough to keep the compression height of the piston within 25mm. Arias, JE, etc. don't like to manufacture custom pistons with comp heights any lower than 25mm. They will do it if you request it, but the ring packs would be so tight that every last land would eventually fail at the slightest sign of detonation. F/I, forget about it!! Also, with the comp height any lower than 25mm, the pin will interfere with the oil rings and you'll have to use buttons.
There are other ways of stroking our motors using the stock crank, which coupled with grinding would be considerably cheaper than purchasing a 40 crank and having to do all the grinding to it.
Check out this thread where you can pull 3.8 from grinding our cranks and if you decide to sleeve and over bore to 100mm can pull 4.0 out of this motor.
https://my350z.com/forum/showthread....highlight=3.8l
I ran the numbers not too long ago for using a VQ40 crank in the VQ35 and what I came up just wouldn't work.
First as you stated, the main journals would have to ground down. So much in fact, that over time cracks may develop around the webs thus leading to crank failure.
Second, the stroke is just to much for the VQ35. The rod big ends will not clear the pan rails nor the bottom of the cylinder bores. Also the piston skirts will contact the counterbalances at BDC. For example, increasing the stock VQ35 crank throw by +3mm, effectively increasing the total stroke +6mm, would require grinding of the pan rails by about .125 to avoid contact with the rod big end. The 40s crank throw is 46mm while the 35s is 40.5mm. That's an increase of +6mm in throw and +12mm total stroke. That's WAY too much for this block. So you see, if you have to grind about an 1/8" just from increasing the throw by +3mm, you'll end up grinding almost through the pan rails if you increased throw by +6mm.
Another problem you'll run into is with the piston comp. height. I could not find a rod length suitable enough to keep the compression height of the piston within 25mm. Arias, JE, etc. don't like to manufacture custom pistons with comp heights any lower than 25mm. They will do it if you request it, but the ring packs would be so tight that every last land would eventually fail at the slightest sign of detonation. F/I, forget about it!! Also, with the comp height any lower than 25mm, the pin will interfere with the oil rings and you'll have to use buttons.
There are other ways of stroking our motors using the stock crank, which coupled with grinding would be considerably cheaper than purchasing a 40 crank and having to do all the grinding to it.
Check out this thread where you can pull 3.8 from grinding our cranks and if you decide to sleeve and over bore to 100mm can pull 4.0 out of this motor.
https://my350z.com/forum/showthread....highlight=3.8l
As for the compression height.. I've built turbo QR's with 24mm compression height.. One, in fact, at 400whp, has been running for 2 years+ with no problems.. with a R/S ratio of 1.48:1, revving to 7K. Using the standard, low silicone alloy.. and coatings.. it works just fine..
The grinding of the mains.. should not be a problem.. Nissan crankshafts are induction hardened.. meaning, they hold thier hardness throughout the entire length/width of the crank. Some cranks are hardened on the surface.. but, Nissan's are hard in and out. So, grinding the crank down, should not present any problems. Also, reducing the counterweight should help. I plan to have it nitrided again after grinding/rebalancing.
I'll check out your thread about using the VQ35 crank and big bore.. But, I'd like to experiment with my own engine and this 4 liter crankshaft, to see what results I can yield. Hey, that's what tuning is all about, right?
Thanks for the suggestions..
Travis
11-25-2005, 11:00 AM
#32
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Originally Posted by punish_her
Another former B15sentra.net guy here (12many2day) to and I definately want to say welcome Travis. This guy deffinately knows his stuff, he has been the go to guy for varrious nissans in the South East for a while.
This guy deffinately has the drive and comitment to get something done.
Travis, hows your shop doing? Havn't been on B15 for a little over a year now, so I lost touch with most every one. Definately keep us up to date. Verry interested in the results, looking for a good reliable stroker.
Mike
This guy deffinately has the drive and comitment to get something done.
Travis, hows your shop doing? Havn't been on B15 for a little over a year now, so I lost touch with most every one. Definately keep us up to date. Verry interested in the results, looking for a good reliable stroker.
Mike
Yeah, it's nice to do something fresh for a change.. We just finished up our destroked QR25.. using a SR20 crankshaft, custom internals, etc etc.. Pretty neat.. is revs to 8700 on our single valvespring/cam package! With a R/S of 1.75:1, it could go higher.. but, we still have to develop a better spring for it to do that. Pretty nice though... made 400whp at under 14psi on pump gas so far..
Travis
11-25-2005, 11:04 AM
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Originally Posted by Trav4011
Hey Mike..
Yeah, it's nice to do something fresh for a change.. We just finished up our destroked QR25.. using a SR20 crankshaft, custom internals, etc etc.. Pretty neat.. is revs to 8700 on our single valvespring/cam package! With a R/S of 1.75:1, it could go higher.. but, we still have to develop a better spring for it to do that. Pretty nice though... made 400whp at under 14psi on pump gas so far..
Travis
Yeah, it's nice to do something fresh for a change.. We just finished up our destroked QR25.. using a SR20 crankshaft, custom internals, etc etc.. Pretty neat.. is revs to 8700 on our single valvespring/cam package! With a R/S of 1.75:1, it could go higher.. but, we still have to develop a better spring for it to do that. Pretty nice though... made 400whp at under 14psi on pump gas so far..
Travis
05-09-2006, 03:20 PM
#36
I think we'll all see that the next gen VQ will have this done as stock. The next gen VQ has a taller deck height than the current gen VQ, and the crank placed lower in the block comparatively. This allows a longer rod for less side loading and lower piston accel. I imagine the new VQ will have the larger main journals on the crank as the VQ40, because it's using the same block. Nissan only has to have one block now and not two (one for the VQ40 and one for the rest), but with different cranks for displacement. The larger mains will be nice, and the longer rod will help with revving, which is probably why Nissan feels comfortable enough to raise the limiter to 7600. Of course, it could actually be a whole new block, but given the information I wouldn't be surprised to find out it's the same, which means stroking the next gen would be as simple as a crank swap without all the machining. Food for thought.
Will
Will
