Whipple Upgrades on 700SCI Engines
03-07-2019 | 11:36 PM
#1
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Joined: Jun 2016
Posts: 48
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From: Huntington Harbor, CA
Whipple Upgrades on 700SCI Engines
Looking to get some more information on the Whipple upgrades and the effects on the 700SCI Engines.
I've read most all information found online and couldn't really find a lot of real world recent testimonials, good or bad, over just a few old threads here on OSO and a couple other sites.
Dennis at Whipple has been helpful and said he is selling quite a few of 700sci upgrades these days and a lot out in the field working well.
I know that most people that have problems with it, don't come on forums and post about it, most likely because of the understanding that adding power means more maintenance/problems.
Background on my engines: They have about 170 hours since rebuilds/checkout at HRE in Florida. Valve train upgraded with Comp cams springs/rockers and Morell Lifters. Compression the same across all cylinders at 140psi and leakdowns are a few 8s, 10s, 12s and a couple 14s so still fresh. The spring pressures tested out at 180lbs, which sound high, but that could be good for increased rpm to prevent float.
Questions:
1. I've read that the 700sci PCMs adjust trims by individual cylinders dynamically, not across all the same. For this to happen, wouldn't there need to be an O2 sensor for each cylinder? Is this just set when the engine is new, but not dynamically adjusted?
The reason I ask is that I spoke with Dennis at Whipple and he said its a blanket map across all cylinders. My concern is that if the engine has been rebuilt, I don't know exactly where the AFR is currently, so if one of the cylinders is lean currently, then adding more boost/fuel might create more problems.
2. How safe is the new tune on the 700sci (AFR, rich vs lean, stress on engine) if the rev limit is maintained up to the stock 5400rpm max therefore not including any valve float issues, just added pressure/stress on the engine up to the stock RPM limit?
I'd like to know if anyone has done a before and after dyno on a 700sci showing more that just HP/TQ that is on Whipples website. ie. showing AFR, EGT, etc. etc.
My primary goals with adding power would be a better overall driving experience in terms of plane time, acceleration straight line/out of turns. Not high rpm max speed, where I know the valve train will then come into play.
I know the NXT trans is only rated at 800hp, but many have this setup with the 700sci and it works well. I also have 6 drives, so those should hold up good.
Anyway, if anyone has more input on overall stress and the effects on the engine up to the stock rpm limit and how the 700sci reacts to the Whipple upgrades, I would really appreciate any more in depth information.
Thank you!
Maury
I've read most all information found online and couldn't really find a lot of real world recent testimonials, good or bad, over just a few old threads here on OSO and a couple other sites.
Dennis at Whipple has been helpful and said he is selling quite a few of 700sci upgrades these days and a lot out in the field working well.
I know that most people that have problems with it, don't come on forums and post about it, most likely because of the understanding that adding power means more maintenance/problems.
Background on my engines: They have about 170 hours since rebuilds/checkout at HRE in Florida. Valve train upgraded with Comp cams springs/rockers and Morell Lifters. Compression the same across all cylinders at 140psi and leakdowns are a few 8s, 10s, 12s and a couple 14s so still fresh. The spring pressures tested out at 180lbs, which sound high, but that could be good for increased rpm to prevent float.
Questions:
1. I've read that the 700sci PCMs adjust trims by individual cylinders dynamically, not across all the same. For this to happen, wouldn't there need to be an O2 sensor for each cylinder? Is this just set when the engine is new, but not dynamically adjusted?
The reason I ask is that I spoke with Dennis at Whipple and he said its a blanket map across all cylinders. My concern is that if the engine has been rebuilt, I don't know exactly where the AFR is currently, so if one of the cylinders is lean currently, then adding more boost/fuel might create more problems.
2. How safe is the new tune on the 700sci (AFR, rich vs lean, stress on engine) if the rev limit is maintained up to the stock 5400rpm max therefore not including any valve float issues, just added pressure/stress on the engine up to the stock RPM limit?
I'd like to know if anyone has done a before and after dyno on a 700sci showing more that just HP/TQ that is on Whipples website. ie. showing AFR, EGT, etc. etc.
My primary goals with adding power would be a better overall driving experience in terms of plane time, acceleration straight line/out of turns. Not high rpm max speed, where I know the valve train will then come into play.
I know the NXT trans is only rated at 800hp, but many have this setup with the 700sci and it works well. I also have 6 drives, so those should hold up good.
Anyway, if anyone has more input on overall stress and the effects on the engine up to the stock rpm limit and how the 700sci reacts to the Whipple upgrades, I would really appreciate any more in depth information.
Thank you!
Maury
03-10-2019 | 09:52 AM
#2
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Joined: Dec 2007
Posts: 912
Likes: 57
From: Solana Beach,CA
Had the same setup in my 382. The boats that did the hp upgrade did have transmission issues. You are a staggered setup? so why not move the engines forward a bit and go with a real transmission? The NXT transmission is a tiny weak link. It uses Bravo gears and will not last.They are also crazy expensive and usually unrepairable. East coast and lake boats do not have Pacific Ocean swells. The loading and unloading of the trans is the issue at speed. I made a suction evacuator for the 1 quart of oil in the trans. Changed it every oil change and it was burnt, (pacific ocean)
The #6 drive is harder to turn than a NXT so thats another issue............Baca and Mobil Matt are 700 experts and your Neighbors.
Good Luck
The #6 drive is harder to turn than a NXT so thats another issue............Baca and Mobil Matt are 700 experts and your Neighbors.
Good Luck
03-10-2019 | 02:15 PM
#3
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Joined: Jun 2016
Posts: 48
Likes: 2
From: Huntington Harbor, CA
That's good advice and feedback! Yes that's the conclusion I'm coming. I think I should be able to suck out the trans oil with the Sureflo pump system I'm using for the engine oil. I'll have to change that now
Teague and others recommend the 72LHP Trans, so I'll check into those. From what I see that could be a drop in solution without moving the rear engine?
I decided not to upgrade the power for now and get through Desert Storm and the summer on the current setup. I'll check the comp/leak down number here in about 70 more hours, which will be 270hrs since rebuild. The plan I'm thinking will be to change the engine/trans oil every 25 hrs to keep all working well, then when I take the engines/heads out for rebuild, swap the trans at that time.
Not sure, but is there any value in used NXT transmissions? Maybe that could be a factor on getting the swap done sooner, but for efficiency sake, I think best to swap out at the next engine rebuild event.
Thanks for your feedback and any further thoughts!
Teague and others recommend the 72LHP Trans, so I'll check into those. From what I see that could be a drop in solution without moving the rear engine?
I decided not to upgrade the power for now and get through Desert Storm and the summer on the current setup. I'll check the comp/leak down number here in about 70 more hours, which will be 270hrs since rebuild. The plan I'm thinking will be to change the engine/trans oil every 25 hrs to keep all working well, then when I take the engines/heads out for rebuild, swap the trans at that time.
Not sure, but is there any value in used NXT transmissions? Maybe that could be a factor on getting the swap done sooner, but for efficiency sake, I think best to swap out at the next engine rebuild event.
Thanks for your feedback and any further thoughts!
