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Bonneville GXP/ Northstar Powered Cars Discuss your Bonneville GXP and/or any other Northstar powered Olds or Cadillac... Including the 3.5L Twin Cam V6 (Short Star ) 4.0L and 4.6L Northstar V8's. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 04-15-2006, 03:37 PM   #11
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Quote:
Originally Posted by gxp rules
The flow is already tuned well for OEM and I wouldnt put steel headers against these aluminum heads(especially with the added heat of nitrous) the block and heads are cast using a "squeeze process" that left them unexpectedly porous and I have read more than one account that the average of a half a quart of oil missing each oil change may be seeping into the block.(god knows what that will do over time.)
This part scares me. I have noticed the past several oil changes, that I am about a 1/2 to full quart low after changing the oil. Does anyone know for sure what the cause is? If it is seeping into the block, where does it accumulate? Will it eventually leak? Does Pontiac know about this? I plan on keeping my GXP for a long time and want to nip this problem early, rather than paying for a fix after my warranty runs out.
Scott
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Old 04-15-2006, 03:41 PM   #12
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Also, can you send a link to the NOS website that you got the kit for your Bonny from? And a part number would help. Does the PCM require ant re-flashing for the addition of the NOS?
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Old 04-15-2006, 07:03 PM   #13
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The Dealer tried to tell me thats just oil burnoff but mine tightend up at about 700-800 miles on it and has'nt smoked since and I've read this oil seeping from a couple of reviews and I tend to believe it'* seeping in. What it does who knows yet. I assume it soaking in like a sponge on the unmachined surfaces.The squeeze process is rather new. I'll dig around when I have time and do some more reading up on it. That seems like alot of oil, maybe there is a limit it can take. There is some higher mileage 04'* out there and I havent heard anything bad about the blocks yet. Warranty or not GM isn't gonna do anything about the matter unless it really presents it self a problem and the process is still used..It does make the block stronger.

I got a recall list also of everything to date but editing and will link to this page....it'* just to long for here


Here'* the Zex Kit for our car
http://www.powerandperformancenews.c...Code=CLEARANCE
Nothing was or can be done with PCM The Extra flow has registered through my sensors fine so far. And Zex is only kit that measures the bottle pressure and governs the gas pressure accordingly so you dont run to rich or lean.
And here are the Instructions ...there on the site but ya gotta dig
http://www.zex.com/Base/Instructions/ZEX140.pdf

Here is an unbelievable video clip of a Mustang GT after nitrousing, but remember you have to have tires burning near 2500 to nitrous on a launch and I havent gotten to a 1st gear nitrous launch yet, but THATS the power this kit will give you. And that Mustang GT(4.6 also) has nothing but the kit on....It'* all OEM other than rearend gears upped to 4.33 , And is under 11 secs in the quarter mile. Its a lighter car and gearing different but the I believe great results will happen to mine also. http://www.zex.com/Information/Whats...ngGTKitweb.wmv

Not sure I want to run mine at 150 shot on the street though. That power level will wear on your bottom end and as you go bigger with the jets; the risk of predetonation increases.
425Hp is alot of power to the crank of a unmodded 4.6

Everything else to install in our car and pics are in this thread with pics and I will make sure I didnt leave any info holes.....was'nt sure if anybody else wanted to go a little faster than the average (GXP owning) bear.
http://www.bonnevilleclub.com/forum/...ic.php?t=52111
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Old 04-16-2006, 05:29 PM   #14
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Wow! Thanks for the info! Did the kit come with the LED'* for purging show off purposes? How long does a bottle last and is it expensive to fill up?
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Old 04-16-2006, 06:52 PM   #15
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No the kits on sale right now for $575 or so . the laser lit purge and selonoid and swiches are an option. And you can get another option that rapid fires the purge like a machine gun and makes people at curb jump back. i have the nitrous and both purge options. Here a video of just the single purge

http://www.zex.com/Products/Files/Ze...-Cloud_LED.wmv

Heres a video of the machine gun module added to the purge

http://www.zex.com/Products/Files/Ze...rgeKitWEB1.wmv

The purges, kits , and pricing all to be found at

www.zex.com

The bottle will last 8-10 quater mile runs according to Zex, I get almost of full nite of parkway fun using at 25-70 MPH and enuff to make intimadating imports look the other way pretending to be distracted with something else.
Bottles are $30-50 to refill depending your area. I have to rely on an auto custom shop hat pays alot of extra liability to keep compressed gas at store and fill bottle * and i pay $50. But with Gas at $3.13 a gallon and a Turbo or */C available only at a few "rich kid with Caddys custom shops" It the way to go I feel and dont regret it.
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Old 04-16-2006, 10:23 PM   #16
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I got a pm asking about the airbox and would like to clarify my position... I would edit into that reply but alot of people dont read back... I am not against altering the airbox, but dont think a wholesale gut of it with holes drilled into it to allow flow from the engine compartment is the way to go. I have been discussing with cballweg about getting better flow.in the '04 sticky and ideas and input would be nice.
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Old 04-17-2006, 11:57 AM   #17
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Quote:
Originally Posted by sahensley
Quote:
Originally Posted by gxp rules
The flow is already tuned well for OEM and I wouldnt put steel headers against these aluminum heads(especially with the added heat of nitrous) the block and heads are cast using a "squeeze process" that left them unexpectedly porous and I have read more than one account that the average of a half a quart of oil missing each oil change may be seeping into the block.(god knows what that will do over time.)
This part scares me. I have noticed the past several oil changes, that I am about a 1/2 to full quart low after changing the oil. Does anyone know for sure what the cause is? If it is seeping into the block, where does it accumulate? Will it eventually leak? Does Pontiac know about this? I plan on keeping my GXP for a long time and want to nip this problem early, rather than paying for a fix after my warranty runs out.
Scott
I am somewhat familiar with the squeeze casting process and at first was't ready to believe that it actually caused a more porous block casting, but... Squeeze casting creates stronger cast parts by casting under very high pressures, therefore (normally) reducing both the quantity and size of air bubbles. Actually, IIRC, the process requires casting, then reheating the casting to plastic state while still in mold and applying high pressure.

This works really well in small parts and pieces I've seen it used on, particularly aluminum pieces. If this issue really exists with the N* block, then it may be due to the complexity of a block casting and the machining that is done afterwards. Any remaining porosity in a casting can be somewhat controlled by; cooling patterns, die design, and die venting. Additionally, porosity tends to exist further into a casting, meaning that light machining often stays in the strongest part of the casting, or outside layer (the "shell" if you will). Heavier machining can sometimes "break through" the stronger "shell" and hit areas of porosity.

Still, all that having been said, it'* almost hard to believe that there could be quarts of porous voids in and engine block...

I don't know if this info adds to the discussion or not and will delete it if deemed wise, lol.
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Old 04-17-2006, 12:31 PM   #18
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Maybe I should rewrite that a little Lash... It didnt make the block "more" porous and the squeeze process does make castings stronger, but the blocks are unexpectedly still porous because oil is still disappearing from them. I agree wih what your saying and it is probably the deeper machining that allows oil to seep in. I havent heard of any dripping of oil out of the newer blocks (2000 and above), but the mystery oil consumption remains at a lower level.

No need for deleting anything LOL this section is a ghost town at times as is. I am well read on the N* but not an expert and discussions lead to knowledge. People just need to respect others views and post their own views along side to consider.
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Old 04-17-2006, 12:37 PM   #19
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I wrote up a history of the LD8 Northstar and first posted on it'* own but after reading it back felt it was worthy of being in the sticky so reposted here and deleted the post




Post subject: History of the Northstar LD8 V8

--------------------------------------------------------------------------------

The LD8(VIN Y) and the L37(VIN9) have been confused by many both here and other places and forums as well.

The L37 is the original V8 from Northstar in 1993. It came out as 295Hp and came in the Allante, Eldorado and Seville STS. The LD8 was brought out in 1994, a variation of the L37 and was detuned to 270 Hp by lowering the cam profile for the smaller Caddys. The L37 was offered in some upper trim levels on these smaller models and I think that lead to the confusion that the STS engine was specifically detuned for Pontiac to use. In 1995 refinements were done that added 5 Hp to each engine and both were made thru 2005.

Also in 1994 the L37 block was bored to 87mm (instead of 93mm) and given to Olsmobile to install in the Aurora. Northstar designated this new variant the L47 with 250 Hp.

The LD8 is a cast aluminum block and heads engine and uses a cast aluminun girdle that replaces the main bearing caps. It has four camshafts and four valves per cylinder. The intake valves are 33mm and the exhaust valves are 29mm. the valves have a direct acting lash adjuster over each valve. And three seperate hydraulic tensioners keep it tight and smooth running. If the one of the chains fail or if the engine is cranked over with a chain removed, the engine is destroyed.

The intake on the LD8 is made of a nylon thermoplastic to reduce the heating of airflow.

The ignition on the LD8 started as 4 coil packs and was changed to 8 coil on plugs in 2000. The crankshaft has two sensosr plus a camshaft sensor gives timing inputs. Also there is a knock sensors on rear head of engine between cylinders 1 and 3. This ignition coupled with fuel injector control makes the LD* do tricks. If the PCM fails or if vital sensors to the PCM fail the engine will stay running at a fixed timing of 10 degrees advanced to limp home. If the PCM registers an overheating issue, it directs the ignition module and injectors to fire only four plugs and injectors, alternating, (the air sucked into non firing cylinders cool the engine) and sets timing to allow it to limp home without any coolant in engine. ( I dont think I would trust this feature since you cant monitor the engine temp and there have been reports of the engine "never being the same afterwards.)

The altenators were liquid cooled for all the Caddys electric bells and whistles but went to air cooled in 2001 to rid it of coolant leak warranty problems.

The LD8 is a disposable engine and though a few minor rebuilders doing "cosmetic rebuilds", there are no major rebuilders for this engine . Critical internal parts are unavailableand the steel cylinder liners cant be replaced or overbored. Same with the heads which have the valve seats and guides hard powder coated and seats cant be reground or the guides replaced. It comes with 100,000 mile platinum tipped spark plugs and150,000 mile antifreeze. There are varied thoughts about this extended life antifreeze and some feel it degrades to gaskets. I'm not taking chances and trading it for normal green. Other than oil and oil filer changes the engine is maintenence free.

The diecast aluminum block of the Northstar has always had oil seepage problems. In the ealier models it was so bad it dripped out of the block. In 2000 Northstar invented a "squeeze casting process" to eliminate block porousity but to this day owners are reporting up to a half a quart or more gone at oil change.

The LD8 is a notorious oil burner and carbon deposit maker. They used to removed all the plugs and soak cylinders with a cleaning fluid, then vacuum out the garbage but have since resorted to doing WOT'* and putting the transmission into second gear at higher rpms to make rings rattle to seat better and scrub the uppermost area'* of the cylinders. The cleaner fluid they used in the old days was GM # 12378545. I'm not sure if it'* still available.

Also stripping bolts to acessory items on engine is common and GM offers a rethread kit J42385-2000
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Old 04-17-2006, 05:51 PM   #20
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Did you buy any different spark plugs for your GXP after installing the ZEX kit? How long and how hard was the install?
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