![]() I'm thinking something like a btr 220 & cid heads for my car. I imagine it drives excellent in that 416 and with an a10 would always be in power on track. #Gpi ss4 no flycut full#i'm not a fan of the lsa or exhaust duration but i think it would drive well in a full weight stick car, in trade for some low end tq. gpi gave me the basic response when i emailed them, leaving almost all of my questions unanswered. i've been eyeing that camshaft for several months. Yes but id expect it to make more power in a 14:1 416. On a STOCK CI engine though I doubt you would see any HP increase over the LT2 set up. The DIFFERENCE in HP was solely due to the MSD and NW103 on a LME 416 engine that wanted more air than the LT2/LT5 combo could provide. The heads were the same using an AMP proprietary port. Porting in general picks up MAYBE 5-7 HP in regards to manifold and TB. The LT2 manifold and LT5 combo were BOTH ported. The ROTOFAB BIG GULP is the same on both. It certainly is not as lumpy an idle as it would have been on a stock cubic inch engine but you can definitely tell something is going on when she fires up LOL Good info, albeit the 14:1 big motor really makes this cam look like a dud. what does the car have for air induction? What cylinder heads are on the car? trying to put this in a format that's easier to digest. I DID NOT want to use a higher stall speed convertor because those inherently have SOME amount of slippage in them and that is NOT really ideal for a road racing application. It is not bad at all but the tranny needs to lock up at a slightly HIGHER RPM level than what the stock convertor is allowing. The ONE thing we ARE going to change is that AMP will be tuning the A10 tranny because the car DOES have some minor surging issues when at idle. Those numbers are indicative of a VERY efficient engine based on the power it produces along with the fact it is on E85 which burns at a 30% faster rate than 93. When driving on the street the car gets 12-13MPG typically. The car with this COMBO gets around 14 MPG on the highway pulling an 800 pound loaded tire trailer at around 80-85 MPH. I run an A10 so the car in track mode is pretty much always in that range and above. My RPM range when tracking is the 4500 RPM range and UP. The LT2 combo picks p a very solid 15-20HP over a stock LT1 manifold though. GWATNEY"s own testing showed that the MSD manifold DOES NOT pick up any additional power on a stock cubic inch engine compared to an LT2 LT5 combo. This is fully evident by the fact that car made 25 more HP than the LT2 combo was producing. Obviously the engine wanted MORE air because it is a LME 416 with VERY good heads on it. #Gpi ss4 no flycut driver#A side note here that this LME 416 has forged pistons with valve reliefs already in them so I could easily run the TRACK ATTACK or SS4 Cam but we felt those cams were a little BIG for the daily driver side ESPECIALLY since I did NOT want to use a higher stall speed convertor. The graph below is THAT cam on my car comparing a side by side comparison of the LT NFC with an LT2 LT5TB and a MSD NW103TB. AMP used a GWATNEY PERFORMANCE LT NFC cam. DI can tolerate more overlap since it doesn't suffer the same reversion issues being that fuel is sprayed directly into the combustion chambers.OK my application is one of a DAILY DRIVER and TRACK car. That is race car stuff.for a street car I would keep overlap under 12 degrees on a DI motor and under 8 degrees on a PI motor. I certainly wouldn't expect a cam with 21 degrees of overlap to behave like stock. There becomes a point when you introduce enough overlap into the system, you will get some odd behavior that you didn't have when stock. I agree it's likely tuning related and not mechanical, However the GPI stage 4 has A LOT more Overlap then a TSP VVT3. Need to make sure that if your tuner left dymanic airflow enabled he tuned the VE correctly. I start at 1300 rpm and go down to 850 rpm after 60s in a linear way.Īfter that it could be your virtual torque table off around idle for certain airmass (more airmass engine cold). If your rpm setpoint cold engine is at 800-900 rpm it is going to surge a lot. GPI stage 4 with milled head and no fly cutting must be really close.ĭoes your engine start right away cold ? When I first tuned my cam I had to bump my cranking airmass a lot and of course adjust my rpm setpoint from cold to hot engine. ![]()
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