Tested My New 3.4/3.6 Motor Yesterday....
01-23-2012, 11:58 PM
#1
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Tested My New 3.4/3.6 Motor Yesterday....
Had a 3.4 converted to 3.6 similar to Logray's build, just not nearly as intensive. With mine we just installed a 3.6 crank and rods into the existing 3.4 cases. There's some minor machining involved, but it's really a very simple install. Cleaned up and slightly decked the OEM 3.4 heads & cams, and took it to Willow Springs. I kept out of the throttle for the first few minutes but gradually opened it up taking it higher into the rev range.
I was running with a friend in his new 3.8 Cayman S with 3.4 heads, etc. He dyno'd at 355 rwhp and I haven't dyno'd mine yet. I'm 200 lbs lighter and we were perfectly matched down the straight so I'm estimating I'm around 290 rwhp. My previous all stock 3.4 was around 270. Laps times on 6-10 HC'd slicks were in the high 1:26's, I've been to 1:25:5 on stickers so that was encouraging. I'll have dyno results Feb 11th when we have a dyno out to WS for POC's season opening race weekend. It revs up really nicely....
I was running with a friend in his new 3.8 Cayman S with 3.4 heads, etc. He dyno'd at 355 rwhp and I haven't dyno'd mine yet. I'm 200 lbs lighter and we were perfectly matched down the straight so I'm estimating I'm around 290 rwhp. My previous all stock 3.4 was around 270. Laps times on 6-10 HC'd slicks were in the high 1:26's, I've been to 1:25:5 on stickers so that was encouraging. I'll have dyno results Feb 11th when we have a dyno out to WS for POC's season opening race weekend. It revs up really nicely....
Last edited by jrgordonsenior; 01-24-2012 at 09:58 AM.
01-24-2012, 11:51 AM
#4
290? Hmmm. My math says more like 310+ RWHP. Sandbagging already?
Simply, since measured acceleration is the same, F=ma shows that the resultant force required at the wheels is proportional to the mass ratio of the two cars. So F1/F2 = m1/m2, and since m1 is 8% (measured) greater than m2 then F1 must be 8% greater. Since we know my measured TQ is (was) 287 lb-ft in the tested RPM range we know that your TQ must be ~ 287/1.08 or 265 lb-ft in that same range (assuming the same effective gearing which we also calculated to be true - using ratios and tire diameters).
Convert this Tq to HP at say 6150 RPM where your engine is likely still making max Tq and the math says 310 RWHP. Extrapolating out a bit further to say 7000 RPM and assuming a 10% drop in Tq at the higher RPM (from other data) yields a potential of 318 RWHP.
Now, my engine was tested at seal level, so we are both likely to see lower numbers at altitude, etc.
Also, I need to choke back this engine to make GT3 class weight (will probably run it at about 315 RWHP), but will hopefully be able to keep most of the tq. It now looks like you may be in that same boat my friend.
See what you get for throwing my HP numbers out in public
This should be a great season JR.
Cheers,
Simply, since measured acceleration is the same, F=ma shows that the resultant force required at the wheels is proportional to the mass ratio of the two cars. So F1/F2 = m1/m2, and since m1 is 8% (measured) greater than m2 then F1 must be 8% greater. Since we know my measured TQ is (was) 287 lb-ft in the tested RPM range we know that your TQ must be ~ 287/1.08 or 265 lb-ft in that same range (assuming the same effective gearing which we also calculated to be true - using ratios and tire diameters).
Convert this Tq to HP at say 6150 RPM where your engine is likely still making max Tq and the math says 310 RWHP. Extrapolating out a bit further to say 7000 RPM and assuming a 10% drop in Tq at the higher RPM (from other data) yields a potential of 318 RWHP.
Now, my engine was tested at seal level, so we are both likely to see lower numbers at altitude, etc.
Also, I need to choke back this engine to make GT3 class weight (will probably run it at about 315 RWHP), but will hopefully be able to keep most of the tq. It now looks like you may be in that same boat my friend.
See what you get for throwing my HP numbers out in public
This should be a great season JR.
Cheers,
01-24-2012, 12:52 PM
#5
Three Wheelin'
Sounds like a great day. Sorry I missed it. Still shaking down my new ride.
LNE 160 thermo
replaced oil plug with Mangetic plug
SS Brake lines
New 997.2 GT3 Shifter
25% from 50% Coolant ratio
Water Wetter
Replace fixed 3rd Brake light and add grounding to fixed 3rd brake light
Paint welded cage areas under the car
Off to Chuckwalla this weekend.
Need to dyno soon. Hope to run with you soon.
LNE 160 thermo
replaced oil plug with Mangetic plug
SS Brake lines
New 997.2 GT3 Shifter
25% from 50% Coolant ratio
Water Wetter
Replace fixed 3rd Brake light and add grounding to fixed 3rd brake light
Paint welded cage areas under the car
Off to Chuckwalla this weekend.
Need to dyno soon. Hope to run with you soon.
01-24-2012, 07:43 PM
#6
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290? Hmmm. My math says more like 310+ RWHP. Sandbagging already?
Simply, since measured acceleration is the same, F=ma shows that the resultant force required at the wheels is proportional to the mass ratio of the two cars. So F1/F2 = m1/m2, and since m1 is 8% (measured) greater than m2 then F1 must be 8% greater. Since we know my measured TQ is (was) 287 lb-ft in the tested RPM range we know that your TQ must be ~ 287/1.08 or 265 lb-ft in that same range (assuming the same effective gearing which we also calculated to be true - using ratios and tire diameters).
Convert this Tq to HP at say 6150 RPM where your engine is likely still making max Tq and the math says 310 RWHP. Extrapolating out a bit further to say 7000 RPM and assuming a 10% drop in Tq at the higher RPM (from other data) yields a potential of 318 RWHP.
Now, my engine was tested at seal level, so we are both likely to see lower numbers at altitude, etc.
Also, I need to choke back this engine to make GT3 class weight (will probably run it at about 315 RWHP), but will hopefully be able to keep most of the tq. It now looks like you may be in that same boat my friend.
See what you get for throwing my HP numbers out in public
This should be a great season JR.
Cheers,
Simply, since measured acceleration is the same, F=ma shows that the resultant force required at the wheels is proportional to the mass ratio of the two cars. So F1/F2 = m1/m2, and since m1 is 8% (measured) greater than m2 then F1 must be 8% greater. Since we know my measured TQ is (was) 287 lb-ft in the tested RPM range we know that your TQ must be ~ 287/1.08 or 265 lb-ft in that same range (assuming the same effective gearing which we also calculated to be true - using ratios and tire diameters).
Convert this Tq to HP at say 6150 RPM where your engine is likely still making max Tq and the math says 310 RWHP. Extrapolating out a bit further to say 7000 RPM and assuming a 10% drop in Tq at the higher RPM (from other data) yields a potential of 318 RWHP.
Now, my engine was tested at seal level, so we are both likely to see lower numbers at altitude, etc.
Also, I need to choke back this engine to make GT3 class weight (will probably run it at about 315 RWHP), but will hopefully be able to keep most of the tq. It now looks like you may be in that same boat my friend.
See what you get for throwing my HP numbers out in public
This should be a great season JR.
Cheers,
....
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01-24-2012, 09:34 PM
#8
Are rebuilds like this normally broken in on a dyno or by driving?
01-24-2012, 11:00 PM
#9
Three Wheelin'
HAH, fun read above. LOL.
Randy: used parts probably not as much need for a break in.... but if it's new crank, rods, bearings, and bearing carrier, or even just new bearings yes they do have a break in. Certainly if the pistons were re-ringed they require break in.
Randy: used parts probably not as much need for a break in.... but if it's new crank, rods, bearings, and bearing carrier, or even just new bearings yes they do have a break in. Certainly if the pistons were re-ringed they require break in.
01-25-2012, 11:04 AM
#11
01-25-2012, 11:54 AM
#13
Three Wheelin'
The 3.6L crankshaft is stronger and bigger than the 3.4L, and also has a longer stroke.
I suppose one advantage of doing it this way might be that you wouldn't also have to replace your DME (and immobilizer/etc.) because the 1999 3.4L DME v5.2.2 doesn't know how to deal with variocam plus in the 3.6L heads.
As a side note, since I own my car forever at this point some years down the road I might make a project to replace my 1999 DME with something newer, and then maybe I can bolt on some 3.6L heads to my "new" Nikied 3.6L engine. :-) wait... that probably wouldn't work.
I suppose one advantage of doing it this way might be that you wouldn't also have to replace your DME (and immobilizer/etc.) because the 1999 3.4L DME v5.2.2 doesn't know how to deal with variocam plus in the 3.6L heads.
As a side note, since I own my car forever at this point some years down the road I might make a project to replace my 1999 DME with something newer, and then maybe I can bolt on some 3.6L heads to my "new" Nikied 3.6L engine. :-) wait... that probably wouldn't work.
Last edited by logray; 01-25-2012 at 12:21 PM.
01-25-2012, 12:31 PM
#14
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The 3.6L crankshaft is stronger and bigger than the 3.4L, and also has a longer stroke.
I suppose one advantage of doing it this way might be that you wouldn't also have to replace your DME (and immobilizer/etc.) because the 1999 3.4L DME v5.2.2 doesn't know how to deal with variocam plus in the 3.6L heads.
As a side note, since I own my car forever at this point some years down the road I might make a project to replace my 1999 DME with something newer, and then maybe I can bolt on some 3.6L heads to my "new" Nikied 3.6L engine. :-)
I suppose one advantage of doing it this way might be that you wouldn't also have to replace your DME (and immobilizer/etc.) because the 1999 3.4L DME v5.2.2 doesn't know how to deal with variocam plus in the 3.6L heads.
As a side note, since I own my car forever at this point some years down the road I might make a project to replace my 1999 DME with something newer, and then maybe I can bolt on some 3.6L heads to my "new" Nikied 3.6L engine. :-)
01-25-2012, 01:36 PM
#15
No real advantage to the 3.4 heads other than I aready owned them. The M97 heads for the 3.4 and 3.8 are identical (same valves, cams, etc) except for the AOS ports (AOS on the 3.4 sits on the head).
In addition to already owning the heads, running the 3.4 allowed me to retain the twin chamber motorsorts AOS (with some trick plumbing by Vision) that does not fit on the 3.8, and run the IMS from my old 3.4.
Cheers,