93 K2500 Suburban 454 Holley Sniper Upgrade

[LC2NLS6]

****, maybe I shouldn't try to keep the GM dizzy if it means i need to keep the stock computer? I was just trying to avoid spending the extra $$ on the hyperspark......might be a dumb way to save?

Makes sense on all other things. That last sentence has me scratching my head though, where is that piece?

You need a computer to control the transmission, unless its a stick. The holley would still control the timing, I think. I think you have to buy a special holley adapter for the small cap hei I think the stock tbi uses. The diverter basket is inside the engine oil galley where the oil cooler lines go in the block. I removed the fittings when getting engine rebuilt, stock basket broke off inside the engine = not fun. I ended up removing a bypass under the filter adapter and pushing the broken piece out that hole, and put in a new bypass valve.

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[8flat]

Ahhhhh gotcha. Yeah luckily mine is a manual. Had the NV4500 rebuilt last summer, and put in a custom clutch, getting my drive train setup for a rebuild similar to yours maybe next year, I want to be in that 425hp/550tq range if I can. SO if/when I rebuild this engine I'll keep that diverter basket in mind, thanks for the heads up.

Yep in talking with efisystempro tech, I just have to get a little cable and the sniper will control timing since we have the small cap HEI.

I've learned more in this thread than I did in 5hrs of reading about sniper conversions in all the other places haha

 

[ccreddell]

Ahhhhh gotcha. Yeah luckily mine is a manual. Had the NV4500 rebuilt last summer, and put in a custom clutch, getting my drive train setup for a rebuild similar to yours maybe next year, I want to be in that 425hp/550tq range if I can. SO if/when I rebuild this engine I'll keep that diverter basket in mind, thanks for the heads up.

Yep in talking with efisystempro tech, I just have to get a little cable and the sniper will control timing since we have the small cap HEI.

I've learned more in this thread than I did in 5hrs of reading about sniper conversions in all the other places haha

https://www.onallcylinders.com/2017/01/20/ask-away-jeff-smith-rotor-phasing-relates-efi/

 

[8flat]

https://www.onallcylinders.com/2017/01/20/ask-away-jeff-smith-rotor-phasing-relates-efi/

THanks for posting, that is a good explanation of what I have going on. I like how he explained phasing, makes a lot of sense. Good stuff.

 

[LC2NLS6]

Towing update - just hooked up a enclosed 8.5x20 car hauler - this thing has torque. I really didn't know it was back there compared to last summer with the boat hooked up, similar weight at 4000 lbs. This thing for sure has 475-500 ft lbs, maybe more at the crank at low rpm. I'd guess hp is 350-375. I'll go drag the boat around in a couple weeks and test that. Rock solid towing, 183F on the coolant temp and 70F MAT with ambient at 30F ish.

 

[Christian Steffen]

Towing update - just hooked up a enclosed 8.5x20 car hauler - this thing has torque. I really didn't know it was back there compared to last summer with the boat hooked up, similar weight at 4000 lbs. This thing for sure has 475-500 ft lbs, maybe more at the crank at low rpm. I'd guess hp is 350-375. I'll go drag the boat around in a couple weeks and test that. Rock solid towing, 183F on the coolant temp and 70F MAT with ambient at 30F ish.

That's awesome to hear!

 

[Supercharged111]

Towing update - just hooked up a enclosed 8.5x20 car hauler - this thing has torque. I really didn't know it was back there compared to last summer with the boat hooked up, similar weight at 4000 lbs. This thing for sure has 475-500 ft lbs, maybe more at the crank at low rpm. I'd guess hp is 350-375. I'll go drag the boat around in a couple weeks and test that. Rock solid towing, 183F on the coolant temp and 70F MAT with ambient at 30F ish.

4000#? 20'?

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[LC2NLS6]

Pro tip - save the tune, then transfer learning to base before clearing the learning and saving. Kids rolled chair over the laptop power cable so I can't access my old tunes either. I just ran the wizard this morning and letting it learn all over again. Seems like if you hold constant load and tps, it learns quicker on that cell. One trip to town and back its almost about 80-90% learned up again.

 

[OBS_George]

So how did you get the trans to shift with the factory computer? I read through the thread an I think I'm just confused a bit. Doing a similar set up on my 93 K1500 but I have a Vortech supercharger to throw on.

 

[LC2NLS6]

So how did you get the trans to shift with the factory computer? I read through the thread an I think I'm just confused a bit. Doing a similar set up on my 93 K1500 but I have a Vortech supercharger to throw on.

I used a caspers Y harness for the TPS sensor, hooked up tach signal from sniper to factory tach lead output spade connector, and kept all factory temp sensors hooked up, plus one new one for the Holley on intake manifold. It's been a while, I think that was the three sensor types it needed to figure out how to shift on the factory computer. If I had to do it all over again, just buy the $3200 Holley Terminator setup and have ability to customize the trans since it comes with built in GM trans controller, though it might need a harness adapter that Holley sells for the newer 93 up 4L80E plug which mine has since it was done when it was rebuilt.