Peninsular Performance Turbo Vs GM8

[DogDiesel]

Response to TOPIC: Tankers Engine, comparison of GM8 to Peninsular's Non-waste-gated Performance Turbo.

Truck: 1 ton 1993 SRW, low-compression, ported, ceramic coated heads and manifolds, balanced. Marine MFI and hi-pop injectors--truck is 5 speed & 4WD.

Bottom line advice: If your GM8 is controlling boost, keep your money. But if like in my case, the low-compression overwelms the GM8 and boost controller simply cannot be adjusted to regulate boost at full throttle, the Peninsular Performance Turbo is the best solution out there, right now.

First impression: Peninsular Performance turbo (PPT) gets grade of A minus to solid A. Does not get A plus rating, because at take-off with 5 speed, there is a little dark exhaust, but quickly clears up. The plume of exhaust is not white and clear like the GM-8, but it makes the same to more power than the GM-8, and mine will now rapp to 4K + rpm if I so desire. Full power across the RPM spectrum. Since installing my low compression engine, I had ABSOLUTELY never been able to use full throttle with the GM8. Low compression engine's incredible exhaust output overwelmed GM8 past 2500 rpm. But GM-8 did pull wonderful up to 2500, very torquey.

PPT Bolt ON?: yes and NO. Had to drill out bolt-holes for oil return tube(10mm x30-35mm vs 8mm OEM). Had to rotate the exhaust and inlet to install on intercooled engine. Had to flatten inlet intercooler pipe to intake, where it would hit turbo and AC unit. Installation rating--not difficult.

Power. Overall, will make more power than GM-8.

Boost PSI: The GM8 will make higher boost than the PPT, but backpressure is less on PPT. PPT makes power even at low boost, any PSI above 3PSI is clean exhaust.

LOAD: I pulled a 24'GN trailer to NY and Ontario-Canada from NC. 14 MPG empty. Hauled back tractor loader attachment/bucket and AC HD5G loader crawler. Will not quote actual weight, but load was an absolute test of any 1 ton. Did weigh truck/trailer/load in VA and it was much more than I thought... Truck would pull load on cruise up 3-4% grades, the torque is incredible. 5%-7% pulled with gear down. Pulled 5 mile 7% grades on I-64 at 35-40MPH (not bad). Engine temps pulling above 25 MPH NEVER went past 195 degrees! Exhaust temp max was 650 degrees at 10" down pipe, both proving the boost and intercooler work! Traffic stop on 7% and 2 mile long 2d gear pull below intercooler speed showed 205 engine temps and 700 EGT, both which dropped at hilltop. Average engine temp was 170 and EGT average was 450-500. Intercooling works.

PPT max boost on my truck. 10-13 PSI, with 9-10 being the average peak boost. Did not seem to need more. Since temperatures with this incredible load were so low, would say boost was just fine.

Non-positive PPT finding. On heavy pull geardown with load, 5th to 4th is always full throttle hammer scenario. However, each 4th to 3rd, max throttle above 2900 stalled the PPT turbo, resulting in zero boost and black smoke. Let-up throttle and boost regain, and lighten the throttle, and the PPT can rapp to max. Interpretation--engine makes way too much power for 3d gear max throttle, and heavy foot exhaust output of low compression at full throttle on long pulls signals over-fueling. Back out of the throttle. Save diesel.

WAYNE's OPINION BOTTOM LINE. The PPT won't make your 1 ton competitive at NASCAR. It will make your 1 ton low compression more than competitive with Dodge and FORDs for pulling. The ease that my truck went from 0-35 with this load is incredible. To pull on cruise at 55-60 MPH with this load is simply awesome. And to do it with such low engine and Exhaust temperatures is phenominal. The low-compression 6.5TDA and Peninsular non-wastegated turbo definately get more than a passing grade.

Wayne

[ 08-03-2003, 07:34 PM: Message edited by: DogDiesel ]

[patrick m.]

Great post Wayne! just the type of info some of us have been looking for.
can you describe the difference in noise between the two (turbo whine/whistle)

[DogDiesel]

First, let me state: What I am saying is MY OPINION, and not reflective of engineering. I leave that for the guys who put the money into research and testing and market the stuff.

Noise: Turbo whine... My low-compression engine is just not tame like a stock 6.5TD. Those high pop injectors make for some noise, so turbo whine is not an issue. My engine does not purr at idle, it hammers and roars. Like comparing the old 5.9 cummins at 160 HP to the 240 HP rattle box.

However, with the GM8 I heard no baritone in my exhaust, but the PPT definitely brings out the true baritone exhaust note. Not louder, just more clear.

Do I recommend a PPT for a OEM 21.5 Compression engine? NO. No. No. No. Keep your money, the GM 4-8 can be taken thru the power modifications in most cases capable with, even up to intercooling. The GM 4-8 gets boost quicker, and can make higher PSI boost. With a stock compression engine, I could regulate boost up to 14 PSI, and peaks of 19. Even a GM4 will keep for clear exhaust. I understand (hearsay) that the GM8 with EFI, held by vacuum works better than with a manual controller.

While I could regulate boost on my engine while stock, I could not on the low compression engine. It just would not regulate. I tried everything. (I re-engineered the Heath turbo kit, reshaping brackets, I even made a home-brew setup (which worked better, that had a 6" linkaage arm and stiff spring) The turbo was in great shape (GM8) but it is overmatched with the exhaust output. Even the PPT will stall the turbo if I floor it in the low gears pulling a grade.

I believe the PPT would be an overmatch for a standard compression 6.5 and the lower boost would be a non-plus for a tweaked up and modified stock engine, and a smoke maker for a totally stock engine.

But that is just my opinion. I'm sure there are others who have a different perspective. Perhaps a truck with an automatic would have even different issues than I dealt with. I feel pretty sure the automatics would not get the turbo dump scenario on down shift like I described with my 5 speed.

I would not mind a few PSI higher boost, but that product is just not on the market in a non-wastegated turbo, unless you spray for misquitos at every start off like with Peninsulars BIG 300 HP turbo. The PPT makes enough smoke to make hairs bristle on the tree-huggers under full throttle.

Wayne
Please disregard comments in my signature that say 19 PSI, the PPT on my truck won't make peaks that high. I will sometime edit the signature to reflect the recent mod.

[ 08-03-2003, 07:23 PM: Message edited by: DogDiesel ]

[Jim P]

What do you mean by not being able to regulate the boost with the lower compression. My engine is 18:1 and I am using a homemade wastegate controler that took about half an hour to make. My truck does have high flow injectors but I have no problem regulating the boost. I can adjust it by running the nut in or out. I first had it set at 12 psi but then took it up to 20psi. It was a little hard to take off in 2nd gear without smoking the back tires. Now I have it set at 18psi. I think I will turn it down a little till I get a pyrometer.

Jim P.

[Jim P]

I forgot to say that my turbo is a gm 4.

Jim P.

[gmctd]

Excellent post, Wayne - very informative. Lower boost pressure makes more power due to less exhaust back-pressure, but quick spool-up is missing for the same reason. Without the GM-8 restrictive exhaust, the normally-aspirated function shoud also be more noticeable, with less boost required under no-load conditions.
Less boost, lower intake air temp, lower egt, lower engine coolant temps - win, win.

jd

[DogDiesel]

Pictures of my GN trailer load.
http://dexta.20m.com/custom3.html

Tires are in gravel in this picture. Could lock the brakes on trailer and slide tires on pavement. Load towed smooth.

Mileage towing was 9.26 MPG. 14 MPG towing empty GN trailer to NY.

Ran the load over CAT scales in southern Virginia and was just frankly shocked. But amazed at the low-compression 6.5TDA pulling capacity. Many want to query the Powerstroke and Cummins comparison. I'd suggest there will be many of those two powerplants in similar riggs that would not pull this load, if not more than a few, especially automatics.

It pulled on cruise at 60-62MPH most of the trip.
To feel it pulling a grade was awesome.

If I'd known the load was that heavy, I'd have made two trips. But the truck did not give the load away as heavy. Acceleration 0-40 was awesome. It ran right thru the RPM with no strain.

Wayne.

[ 08-07-2003, 04:27 AM: Message edited by: DogDiesel ]