kmetiuk
10+ Year Contributor
- 521
- 125
- Mar 10, 2010
-
Edmonton,
AB_Canada
Tech changes.....companies change management....materials get switched out for "better" ones.....vendor XX is sourcing Chinese steel....or any number of things can change how parts come out of various vendors so I am curious what's everyone's current goto setup for rods and pistons.
I've searched lots and read lots but as stated above shiiit changes all z time.
I am just planning out my motor build the last couple of days and have researched a lot and have a good idea of where I am going but I wanted to hear what peeps current opinions are on rods and pistons
Basically I am considering a 2.0, 2.0LR, or a 2.1 destroked (6 bolt preferable but there are some 7-bolts in the local pick a part) with a raised RPM limit of 10K.
My end goal is road racing....with only ~5000 km/yr of crusing around town or wherever. I rarely drive my DSM on the street as I HATE leaving it anywhere unattended. I have had 6 attempted break ins in the last 2 years alone. Each time I have to replace the door handles and pop the dents out....last time they were prying on my hood and really fcucked up the hood latch mech and rad support. I dunno why, but my DSM is a magnet for little punk bitches.
As far as racing goes a 10K RPM would clearly be advantageous but with the RPM at the high end for an hour or more at a time there is a lot to consider. Check my DSM profile for mods and you'll see I am well on my way with the mods to support road racing and if you check my build log I have the skills to do whatever I need too in order to hit my goal. Now I know there maybe issues with shifting at those high RPM's but I have a few ideas there too....plus its not like I need super low shift times b/c I am trying to get under 9.5s at the drag strip.
Current installed turbo is a Holset HE351VE which I plan to run at about 30 PSI (set at 22 right now as my engine suuuuucks) to keep the torque in the tranny down in the ~450 ftlb range. I don't need nor want any more boost than that as tranny longevity is the main concern. However, to max out the Holset I need more RPM's to get near that 69 lb/min choke...plus its road racing so more power band is clearly better as well.
For anyone that's curious or pessimistic about using such a HUGE turbo for road racing: I have ran the math on the comp map and I used the pressure ratios that I am seeing at XX RPM logged in DSMLink along with the VE's from my SD table at that PR and RPM to calculate the lb/min using the proper equation. I assumed a 100F intake air temp as it varies so much and it's average-ie-ish from the logs. The lb/min calculated very VERY closely matches to what DSMLink was logging at 22 psi. I was surprised how accurate the comp maps were so with that confidence I bumped the pressure upto 30 psi and extended the RPM range to 10K and found I am around 62 lb/min calculated which is fine as the comp efficiency is dropping off already anyways.
Since the HE351VE has a 24 CM turbine housing (or a 1.85 AR) I have MORE than even housing to push that much boost at that RPM....and with my elec controller moving the vanes I am getting full boost (22 psi) at ~4000 RPM in 3rd gear (logged...which is the surge limit anyways and I actually had to tone my controller down a bit to just ride that limit) and by 4500 in 2nd gear (logged). So with the raised RPM limit I am looking at a near 6000 RPM power band which will be suuuuuper fun on the track. I have tested and tested and tested the shiiit outta my controller and if I am at or above 4500 RPM in 2nd or above gears; the boost takes 0.88 seconds to hit +20 psi according to Link. When racing your rarely (if ever) below 5000 RPM so insta boost and a huge azz power band should make for some awesome fun.
This is still on stock cams as well which I plan on changing to move my peak torque to the 6000 RPM range. From histograms of the RPM from logs of other racers I see that the majority of your time is spent in the 5000-7000 range anyways so its not like im at 10000 RPM for an hour straight....more like 5000-7000 range for ~70% of the race duration.
So that's my plan and based on that I need MOAR RPM to hit that 6K RPM power band so my thoughts on engines are:
2.1DS: seems like a hassle to deal with the block if something goes south in the future so that's pretty much off the list...but dat rod ratio tho.
2.0: Clearly the easiest to build and find the rods/pistons for but the rod ratio has been concerned since road racing will have that RPM up high for an hour or more straight.
2.0LR: With a rod ratio of 1.77 vs the 1.84 of the 2.1 and the 1.7 of the 2.0 this seems like a good middle ground. From what I have read there are several 2.0's that have been rev'd upto 10,000 RPM without issue so a better rod ratio gives more peace of mind.
The rods/pistons availability is also part of the consideration. Clearly 162mm and 156mm rods are not as readily avaiable as the 150mm...but they are out there currently. Pistons with the 1.130" comp height are also found easily currently so that doesn't seem to be an issue....so it basically comes down to brand and model of rod and piston.
Not sure what to get for rods/pistons as far as brand/model so here we are....what do you like and why?
I've searched lots and read lots but as stated above shiiit changes all z time.
I am just planning out my motor build the last couple of days and have researched a lot and have a good idea of where I am going but I wanted to hear what peeps current opinions are on rods and pistons
Basically I am considering a 2.0, 2.0LR, or a 2.1 destroked (6 bolt preferable but there are some 7-bolts in the local pick a part) with a raised RPM limit of 10K.
My end goal is road racing....with only ~5000 km/yr of crusing around town or wherever. I rarely drive my DSM on the street as I HATE leaving it anywhere unattended. I have had 6 attempted break ins in the last 2 years alone. Each time I have to replace the door handles and pop the dents out....last time they were prying on my hood and really fcucked up the hood latch mech and rad support. I dunno why, but my DSM is a magnet for little punk bitches.
As far as racing goes a 10K RPM would clearly be advantageous but with the RPM at the high end for an hour or more at a time there is a lot to consider. Check my DSM profile for mods and you'll see I am well on my way with the mods to support road racing and if you check my build log I have the skills to do whatever I need too in order to hit my goal. Now I know there maybe issues with shifting at those high RPM's but I have a few ideas there too....plus its not like I need super low shift times b/c I am trying to get under 9.5s at the drag strip.
Current installed turbo is a Holset HE351VE which I plan to run at about 30 PSI (set at 22 right now as my engine suuuuucks) to keep the torque in the tranny down in the ~450 ftlb range. I don't need nor want any more boost than that as tranny longevity is the main concern. However, to max out the Holset I need more RPM's to get near that 69 lb/min choke...plus its road racing so more power band is clearly better as well.
For anyone that's curious or pessimistic about using such a HUGE turbo for road racing: I have ran the math on the comp map and I used the pressure ratios that I am seeing at XX RPM logged in DSMLink along with the VE's from my SD table at that PR and RPM to calculate the lb/min using the proper equation. I assumed a 100F intake air temp as it varies so much and it's average-ie-ish from the logs. The lb/min calculated very VERY closely matches to what DSMLink was logging at 22 psi. I was surprised how accurate the comp maps were so with that confidence I bumped the pressure upto 30 psi and extended the RPM range to 10K and found I am around 62 lb/min calculated which is fine as the comp efficiency is dropping off already anyways.
Since the HE351VE has a 24 CM turbine housing (or a 1.85 AR) I have MORE than even housing to push that much boost at that RPM....and with my elec controller moving the vanes I am getting full boost (22 psi) at ~4000 RPM in 3rd gear (logged...which is the surge limit anyways and I actually had to tone my controller down a bit to just ride that limit) and by 4500 in 2nd gear (logged). So with the raised RPM limit I am looking at a near 6000 RPM power band which will be suuuuuper fun on the track. I have tested and tested and tested the shiiit outta my controller and if I am at or above 4500 RPM in 2nd or above gears; the boost takes 0.88 seconds to hit +20 psi according to Link. When racing your rarely (if ever) below 5000 RPM so insta boost and a huge azz power band should make for some awesome fun.
This is still on stock cams as well which I plan on changing to move my peak torque to the 6000 RPM range. From histograms of the RPM from logs of other racers I see that the majority of your time is spent in the 5000-7000 range anyways so its not like im at 10000 RPM for an hour straight....more like 5000-7000 range for ~70% of the race duration.
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So that's my plan and based on that I need MOAR RPM to hit that 6K RPM power band so my thoughts on engines are:
2.1DS: seems like a hassle to deal with the block if something goes south in the future so that's pretty much off the list...but dat rod ratio tho.
2.0: Clearly the easiest to build and find the rods/pistons for but the rod ratio has been concerned since road racing will have that RPM up high for an hour or more straight.
2.0LR: With a rod ratio of 1.77 vs the 1.84 of the 2.1 and the 1.7 of the 2.0 this seems like a good middle ground. From what I have read there are several 2.0's that have been rev'd upto 10,000 RPM without issue so a better rod ratio gives more peace of mind.
The rods/pistons availability is also part of the consideration. Clearly 162mm and 156mm rods are not as readily avaiable as the 150mm...but they are out there currently. Pistons with the 1.130" comp height are also found easily currently so that doesn't seem to be an issue....so it basically comes down to brand and model of rod and piston.
Not sure what to get for rods/pistons as far as brand/model so here we are....what do you like and why?
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