VT roller engine- vn v8 5 speed. tuning required?

[vn304turbo]

Just wondering if anyone mighy be able to confirm for me that im more than likely going to need to retune the factory vn v8 manual memcal with the important bits from the vt tune to run the roller cam engine? Or is the vn tune close enough

[delcowizzid]

it probably wont run too badly if its totally stock .and with the realtime tuning gear off this site it wouldnt take much messing round to get it running its best would only have to touch 2 tables in the tune to fix any discrepancies VE and spark advance

[Dazza92VP]

I can confirm your going to have problems with idle in drive it will try and stall also don't forget to fit the IAT into the manifold not into the air box

[vn304turbo]

Thanks for the speedy replies guys, I am going to have a chatvwith vl400 about nvram and associated rt gear, the engine thats going in is bog stock vt roller cam engine, I havnt had any tuning experience altho I am pretty cluey with a pc so with all the info on here it shouldnt be too hard to nut it out. Im going to try an use as many vn sensors as possible to keep the factory loom, or whats left of it after the dog chewed the two coolant sensor lugs and te iac and tps connectors

[immortality]

Isn't the VT dizzy a bit different to the earlier VN-VS models.

[Helical]

If you're using the VN loom you'll also have to adapt the dizzy plug as the VT has an extra terminal for the crank angle sensor. You can leave that terminal out and just connect the others, they do the same thing. I know the VS has the same colours as VT, guessing the VN would too.

To run the coolant sensor for the dash gauge you will need to drill and tap a hole in the front of the intake manifold or use a VN/VR/VS manifold as they deleted the hole and sender on the VT.

The VT uses an electric canister (emissions) purge valve so if you're still running that you'll want to use the vacuum operated one off the VN/VR/VS.

Other than that should be the same and I would expect it to run the same as a VN motor on the same tune. As long as it's a T5 not a Getrag you won't have to worry about the g/box. If it is the Getrag you will have problems with the speed sensor as the Getrag runs a reluctor sensor and the T5 a hall effect. The VN tune will want the hall effect.

I'm not too familiar with VN as I have VS's, but if you wanted to update the tune/wiring/ecu you could possibly get a hold of a VS series 3 V8 loom and PCM. Body to engine plugs are the same as earlier VS where as VT loom is very different. Just need to change the speed sensor wiring on the VS3 loom and change some flags in the tune to get the PCM to read the vehicle speed. I was running a VT 304 with a standard T5 box, VS series 3 engine loom with the g/box part of the loom changed to VS 1/2. I was running the HSV 195 tune with no hassles, just changed the speed sensor flags as mentioned.

Troy

[vn304turbo]

Ok so we got rhe enging the other week and have noticed some abnormalities. On the front of the intake manifold the 2 wire temp sensor was never there as the casting was never drilled (as I was expecting) but the dizzy has the vr vs stylr 3 wire plug? My mate swears to me that he witnessed this engine running in a vt but I call bullshit something just doesnt seem right here. My guess is that he has aquired at vs s3 engine maybe s2. Either wau we are going to pull the intake so I can have a squizz in there to be sure if its a roller engine or not. Someone tried to tell me the other day thay vt 5litre roller cam engine also came with roller rockers as factory fitment but I do not believe this to be true

[Dazza92VP]

What's the prefix on the block if its vn, sm or svm then it's a roller if its vu, svu or su its just a standard 304

[vn304turbo]

I knew it!! I will have to go to my mates amd double check but im certain its a VU PREFIX just like all my other engines (I have a few lol)

[Helical]

... Someone tried to tell me the other day thay vt 5litre roller cam engine also came with roller rockers as factory fitment but I do not believe this to be true

I was told that one too, but I've never seen one with roller rockers from factory.

Differences I know between VT S1 5.0L and VS S3 5.0L is that the VT runs serpentine style belts for everything other than PS, has two 02 sensors, and the coolant sensor as mentioned previously. Otherwise they are physically the same.

The prefix will tell you the truth.