is timing retard needed for a 150 shot?

I have a built motor and A4 trans all suspension done and I want to spray a 150 wet shot, I've been doing some research and some of the nitrous companies claim no timing retard needed for their kits up to 150 shot. Now I've never used spray before but I remember reading to retard the timing
2 * for each 50 hp shot so why would these companies say "no need to retard the timing" ? Is it because the pcm will retard the timing automatically if it senses detonation? if so how is this affected if I have the LT4 km in the pcm?

If your timing is now stock, I would take some timing out using a 150shot and pump gas. Stock LT1/LS1 tuning is pretty aggrssive on timing. It also has an aggressive knock sensor, which is what allows the aggressive timing to work. But KR works only after knock is detected, and when it does it pulls a lot of timing. You don't want to reey on it for those reasons. With N2O, especially with stock pisotns, you want to avoid detonation in the first place. Second, you will end up going slower than having the timing right in the first place. This is because when the PCM pulls timing, it pulls a lot and it does so for a fairly long time. Also, with the juice the burn rate is faster than without and the stock timing will be too advanced for max hp anyway, regardless of detonation.

I would start with about 28-30 degrees of timing, at most, with a 150 shot on a stock shortblock.

Rich

Thanks Rich I will head your advice but my motor is an all forged 383, splayed caps fullt ported heads & intake yada yada. I am going to start off with a mail order tune from madwolf or pcm4less and I have the LTCC. Which N2O kit is better Zex or NX express?

I don't have familiarity with Zex, so I can't comment yea or nay. I have used NX with no problems.

Rich

I would go NX. I don't know if it is the same now but I remember when Zex first came out their 125 shot was only putting down like 81HP to the rear wheels.

NX is notorious for rating their HP at the wheels. So if your spraying a 150 shot, most likely you are seeing very close to that at the rear wheels.

I agree that you will want to pull timing out for best results....when companies list "no timing retard needed", this is assuming you are on stock timing. With the built motor you should have custom spark tables...so you will want to have a way of retarding the timing on spray.

The Zex kits are easy to install and make good power...but I prefer the looks of a standard nitrous kit. We have many different options for the LT1....single nozzle, plate, MAF, DP, etc...if you want to call I would be happy to go over tham with you.

Thanks everyone, Dave I will call you tomorrow.

Thanks everyone, Dave I will call you tomorrow.

Looking forward to talking with you...ask for Ray when you call ;)