LT1 intake and nitrous
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Joined: May 2005
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From: Mount Sterling KY
LT1 intake and nitrous If you see my sig you can see I am running high 9's @4200 lbs. I am running a Harris speed works single fogger and bottom outlet solenoids good for 400 HP with a 175 shot. I have always heard that the LT1 intake is s**ty for nitrous distribution. And that you don't want to run over a 175 shot on them due to this reason. Nitrous is lighter than fuel and the 4 back cylinders will go lean. I am running VP 110 and NGK B8EFS non projected tip plugs gapped at .035. With my AI 200cc heads and AI cam on a Forged 385 with 12.4 to 1 compression I am taking out 3 degrees per 50 shot. My question is if I want to go to a larger shot and continue to take 3 degrees per 50 shot out on 110-116 VP fuel will I be able to keep my current setup and run a 200-250 shot or do I need to to go direct port. I have heard good and bad about the direct port systems. I check number 5,7,6,8 plugs after each run and the timing mark is always great. Opinions?
If you see my sig you can see I am running high 9's @4200 lbs. I am running a Harris speed works single fogger and bottom outlet solenoids good for 400 HP with a 175 shot. I have always heard that the LT1 intake is s**ty for nitrous distribution. And that you don't want to run over a 175 shot on them due to this reason. Nitrous is lighter than fuel and the 4 back cylinders will go lean. I am running VP 110 and NGK B8EFS non projected tip plugs gapped at .035. With my AI 200cc heads and AI cam on a Forged 385 with 12.4 to 1 compression I am taking out 3 degrees per 50 shot. My question is if I want to go to a larger shot and continue to take 3 degrees per 50 shot out on 110-116 VP fuel will I be able to keep my current setup and run a 200-250 shot or do I need to to go direct port. I have heard good and bad about the direct port systems. I check number 5,7,6,8 plugs after each run and the timing mark is always great. Opinions?
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Joined: May 2005
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From: Mount Sterling KY
Because I am still running a stock computer. I have an OBD1 conversion and running speed density but don't think i can spin it high enough to take advantage of a single plane intake. 7150 max on the stock PCM. Plus on my AI HR it's done at 6500 N/A. AI is begging me to do that and do the 24x conversion but as of now I have the fastest Impala with stock casting heads, stock computer, HR, and opti.
DP... I would two stage it and run a small first stage with the fogger, like a 75-100 shot. then use the DP for the final stage of whatever is left that you are willing to spray.
You could use the first stage to launch with and bring in the second after the 60 ft.
You could use the first stage to launch with and bring in the second after the 60 ft.
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From: Deep in the heart of Texas
The way I understand any Tuneport setup, LT1 or F.I engine for that matter with the TB in front of the intake, plate or fogger is susceptible to heavier charges of squeeze in the forward cylinders. Hotrod had an article on this topic back in the later 90's. If I remember right the cylinders were monitored with temp probes on the headers. The front cylinders were burning several hundred degrees hotter than the aft ones. I've heard the distribution is so sensitive that the fogger should be placed in the center of the intake tract so not to overload one side of the engine. On my setup the 2 and 4 cylinders would be getting the largest dose of nitrous. The only way I see even distribution of nitrous across all eight is direct port.
Last edited by 93 LT1 Vette; Jan 3, 2012 at 05:12 PM.
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Thread Starter
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From: Mount Sterling KY
The way I understand any Tuneport setup, LT1 or F.I engine for that matter with the TB in front of the intake, plate or fogger is susceptible to heavier charges of squeeze in the forward cylinders. Hotrod had an article on this topic back in the later 90's. If I remember right the cylinders were monitored with temp probes on the headers. The front cylinders were burning several hundred degrees hotter than the aft ones. I've heard the distribution is so sensitive that the fogger should be placed in the center of the intake tract so not to overload one side of the engine. On my setup the 2 and 4 cylinders would be getting the largest dose of nitrous. The only way I see even distribution of nitrous across all eight is direct port.
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what exactly is holding you back from doing a dp? i've heard of jets clogging with smaller shots, but with what you're wanting to hit it with and with a a nitrous filter i wouldn't worry too much about that
if i remember right anything after a 200 shot should really be done with a direct port set up & all those kits are pretty pricey & that sucks Id love a direct port with about 400 & a progressive controller
High 9s in that car, with that setup, Id say its working pretty good. You also run a pretty safe tune pulling 3 degrees per 50hp on high octane gas. I run my tune a litte more aggressive but Ive got 100% peice of mind in the parts Im spraying. As mentioned, the 4150 setup is going to give you a more even distribution on the spray. Im running a single plane (Vic-E) on my LT1 car for this reason alone. The motor is built for nitrous and hardly makes a pass down the track without it. Im running a plate with a stand alone fuel system. A fogger is always seen as better than a plate setup, I think on stock LT1 intake that is the case. I also think you really need to be at a certain theshold before a fogger is needed. Guys that run foggers are typically on huge shots of nitrous (250-500hp per stage). Not to mention plumbing a fogger is super expensive.
You sound like someone that knows what they are doing. Run the bigger shot on the LT1 intake, check your plugs for excessive heat on those front plugs. On my previous motor (stock LT1 intake), I had dual fogger nozzles plumbed into the rubber before the throttle body. I plumbed one nozzle at 8-9 o'clock and the other nozzle at 3-4 o'clock. This basically split my nitrous shot between 2 fogger nozzles which I like to think helped some with distribution. I can dig up some old pics if that would help.
You sound like someone that knows what they are doing. Run the bigger shot on the LT1 intake, check your plugs for excessive heat on those front plugs. On my previous motor (stock LT1 intake), I had dual fogger nozzles plumbed into the rubber before the throttle body. I plumbed one nozzle at 8-9 o'clock and the other nozzle at 3-4 o'clock. This basically split my nitrous shot between 2 fogger nozzles which I like to think helped some with distribution. I can dig up some old pics if that would help.
I tried a 250 shot once on my old 355 combo. Only got to the top of second gear and had to let out due to a slight detonation for a split second. I melted the #7 and #8 plugs in a very short period of time. I also had added 12 % of fuel via a tune for those cylinders. I ran a 6.3@101 letting out with a crappy 1.5 short time (best 1/8 on the 200 was 6.4@108 with a 1.59 short time in July 95 degree heat). I was neck and neck with a 9.6 car until I had to let out so it would have ran very good had it not had the distribution issues. (I was also running 11.4 AF ratio so I was not lean). I had no problems with the 200 shot and was taking out 8 degrees of timing with C10 in the tank and C16 in my 1 gallon fuel cell. I never got to dial in the 200 shot but it should have went an easy 9.9@134 with a 1.4 60ft. This way way back in 04-05.
The new combo should be running this year and I went with a single plane and a monte smith nos plate jetted up to a 250 shot.
BTW, your call hauls for sure. A 200 hit should get you 1-2 tenths and a couple mph while being safe as far as distribution.
The new combo should be running this year and I went with a single plane and a monte smith nos plate jetted up to a 250 shot.
BTW, your call hauls for sure. A 200 hit should get you 1-2 tenths and a couple mph while being safe as far as distribution.
I am running a 255 walbro intank at 43psi for the motor and a 1 gallon fuel cell with a product engineering 290gph pump 8an reduced to a 6an at the holley regulator. I was running an NX SHO single fogger welded straight shot into a trick flow elbow. The new combo is going to run the same fuel system but with a reacetronix 255lph intank and hotwire kit.
So it was a shark nozzle on low psi.
I'm inclined to believe the nitro Dave's plate on EFI jetting will atomize MUCH better than a single shark nozzle. Haven't tested this theory yet but I'm going to. I wonder of T shep could Chinese in. IIRC he ran a NO plate + DP just before this latest iteration of his nitrous system.
I'm inclined to believe the nitro Dave's plate on EFI jetting will atomize MUCH better than a single shark nozzle. Haven't tested this theory yet but I'm going to. I wonder of T shep could Chinese in. IIRC he ran a NO plate + DP just before this latest iteration of his nitrous system.
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From: Mount Sterling KY
I am looking at piecing together a fogger kit. I can do most the work my self with a 1 gallon cell and low pressure pump. As of now my shark knozzle is drilled and tapped into the back side of the MAF and is only about 3" from the throttle body. May still talk to AI about a single plane or may leave it alone. Hell the car is running 9.90's on a 175 shot.
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Plus after 400 hours of OT this year, I should be able to make this a mute point if you know what I mean LOL. Beautiful car it was a pleasure seeing it and hearing it but a swinging drivers side 6 point would be a must for my broken down old ***.
Nostang, I believe the LT1 pcm can only vary cylinder fuel trims at low rpms, have been told at something like 25-3500rpm it goes batch fire.
I say get the injectors flowed and put the fat ones on the leanest cylinders and tweak it up in small stages.
I say get the injectors flowed and put the fat ones on the leanest cylinders and tweak it up in small stages.
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From: Apopka FL
I run a boosted combo so i am just throwing this out there. Is there a better spot to place the single nozzle? If the nozzle didn't spray off to the side would it work if you centered it in the top of the manifold.
Look at the edelbrock e3.
Look at the edelbrock e3.
Last edited by BIGCAT7274; Jan 4, 2012 at 06:42 PM.