Is The VQ35DE Engine Considered A High Compression Motor?

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• Is the VQ35DE engine considered a high compression motor?

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Diesel350 View Public Profile Find More Posts by Diesel350 View iTrader Profile 03-14-2004 | 07:15 AM #8 jesseenglish New Member Joined: Apr 2003 Posts: 5,563 Likes: 0 From: Earth What's your point? It's not like I could choose between a low or high compression motor when I bought the car. It's really about how the engine is built. Explain how it's safer? With a improperly tuned low compression motor, it will blow just as fast as a high compression one. Maybe you don't have to worry about timing as much, but that's why I've taken care of that as part of my tuning. Like I said, as long as you take it into account it's not a problem. Reply Like jesseenglish View Public Profile Find More Posts by jesseenglish View iTrader Profile 03-14-2004 | 07:15 AM #9 Fear Night Registered User Joined: Mar 2004 Posts: 161 Likes: 0 From: B'ham, AL Compared to other V6s yes its pretty high compression. GM 3.8L is like 8.5:1 I think? Lol Reply Like Fear Night View Public Profile Find More Posts by Fear Night View iTrader Profile 03-14-2004 | 05:22 PM #10 FLY BY Z Registered User Joined: Dec 2002 Posts: 2,700 Likes: 0 From: Maryland Quote: Originally posted by Fear Night Compared to other V6s yes its pretty high compression. GM 3.8L is like 8.5:1 I think? Lol the supercharged 3.8 is 8.5:1 and the NA version is 9.6:1. Interesting that people think the Z is ok with FI and 10.3:1. This is one reason I am not going FI until my warranty is expired on the powertrain. I am not bulletproofing a motor that will be fixed for free right now if something happens. I won't run FI on a motor with this high of compression as it isn't safe. Pulling timing is a band aid and not a real solution. There have been a ton of blown motors with FI already. Not so many anymore as everyone is pulling timing. You will realize a very limited power potential with high compression and boost at a dangerous level of reliability. Reply Like FLY BY Z View Public Profile Find More Posts by FLY BY Z View iTrader Profile 03-14-2004 | 08:11 PM #11 Scorch268 Registered User Joined: May 2003 Posts: 102 Likes: 0 From: Atlanta fly by z, is there anyone who has purchased new pistons to lower compression on this board? Reply Like Scorch268 View Public Profile Find More Posts by Scorch268 View iTrader Profile 03-14-2004 | 08:47 PM #12 FLY BY Z Registered User Joined: Dec 2002 Posts: 2,700 Likes: 0 From: Maryland Quote: Originally posted by Scorch268 fly by z, is there anyone who has purchased new pistons to lower compression on this board? there are at least a few who have. probably more that don't post much. the only name I can remember at the present moment is something like abogado...something. you may need to click the members link up top to search for the exact name and you can PM her. she is from FL. she also has posts in the FI forum. i know there are others but some screen names run together and i can't remember the difference until they post. sorry. i think that even though she has a motor built to take big boost, the problem now is finding an adequate ECU solution to control everything. Reply Like FLY BY Z View Public Profile Find More Posts by FLY BY Z View iTrader Profile 03-15-2004 | 07:18 AM #13 Dissolved Registered User Joined: Sep 2003 Posts: 1,826 Likes: 0 From: ________ Quote: Originally posted by Diesel350 You still will make more total power with a low compression, high boost engine than you will with a high compression, low boost engine. Plus it's safer. Exactly Reply Like Dissolved View Public Profile Find More Posts by Dissolved View iTrader Profile 03-15-2004 | 01:43 PM #14 D'oh Registered User Joined: Jul 2002 Posts: 1,510 Likes: 1 From: Santa Cruz, CA At this juncture in the vq35 aftermarket, low compression or high compression is in some ways a moot point. People still seem to have problems with 8.5+ psi of boost (about 450 RWHP) due to ECU issues. The engine seems to be running fine up to those boost and HP levels, so until that issue is resolved there isn't much of a point in trying to boost even higher. Also, keep in mind that with a high compression ratio you will have more power @ an equivalent boost level than with a lower compression ratio. Keep in mind that you will also have better performance when you are off boost. So, even though you may be able to make more overall power with a high boost/low compression setup, it may not be necessary for most Z owners. In other words, if you are not looking for more than 450 RWHP anyway, then there may not be much of a point in chaging the engine internals to try and get higher boost. People say "It's safer" to have higher boost and lower compression. What does that mean? You still will blow a poorly tuned motor. It's no safer than a high compression motor in that respect. I'd say that the main difference is that it gives you more margin for error when tuning, but if you run a high boost/low comp motor near the edge in terms of performance, you will still be using up most of your margin to extract that extra performance. On the other hand, if you tune a low boost/high comp motor conservatively, it can still be very safe. Plus, there are tons of Turbo Diesels out there, and they have compression ratios of 20:1 or more. The point is that compression ratio is not all that matters. The entire system is what counts. So, in the end, the obvious reason people run F/I on the Z is because they can do it reliably and still make as much power as they require. Once people start really delving into high HP/high cost systems, you will probably see more people look into the low compression internals, but whether it is necessary is really up to what you want to do with the motor. -D'oh! Reply Like D'oh View Public Profile Find More Posts by D'oh View iTrader Profile 03-15-2004 | 02:10 PM #15 aalzuhair New Member iTrader: (2) Joined: Jan 2004 Posts: 1,295 Likes: 0 From: Riyadh, SA Quote: Originally posted by D'oh At this juncture in the vq35 aftermarket, low compression or high compression is in some ways a moot point. People still seem to have problems with 8.5+ psi of boost (about 450 RWHP) due to ECU issues. The engine seems to be running fine up to those boost and HP levels, so until that issue is resolved there isn't much of a point in trying to boost even higher. Also, keep in mind that with a high compression ratio you will have more power @ an equivalent boost level than with a lower compression ratio. Keep in mind that you will also have better performance when you are off boost. So, even though you may be able to make more overall power with a high boost/low compression setup, it may not be necessary for most Z owners. In other words, if you are not looking for more than 450 RWHP anyway, then there may not be much of a point in chaging the engine internals to try and get higher boost. People say "It's safer" to have higher boost and lower compression. What does that mean? You still will blow a poorly tuned motor. It's no safer than a high compression motor in that respect. I'd say that the main difference is that it gives you more margin for error when tuning, but if you run a high boost/low comp motor near the edge in terms of performance, you will still be using up most of your margin to extract that extra performance. On the other hand, if you tune a low boost/high comp motor conservatively, it can still be very safe. Plus, there are tons of Turbo Diesels out there, and they have compression ratios of 20:1 or more. The point is that compression ratio is not all that matters. The entire system is what counts. So, in the end, the obvious reason people run F/I on the Z is because they can do it reliably and still make as much power as they require. Once people start really delving into high HP/high cost systems, you will probably see more people look into the low compression internals, but whether it is necessary is really up to what you want to do with the motor. -D'oh! Thanks Very nice post Reply Like aalzuhair View Public Profile Visit aalzuhair's homepage! Find More Posts by aalzuhair View iTrader Profile 03-15-2004 | 02:23 PM #16 zeroday Registered User Joined: Jan 2003 Posts: 1,199 Likes: 0 From: . the question posted by the thread starter was obviously loaded but i'm still trying to figure out why.... how else can you explain first asking if the vq is considered a high compression engine, then a few posts later explaining to someone how to calculate compression ratios... Reply Like zeroday View Public Profile Find More Posts by zeroday View iTrader Profile 03-16-2004 | 10:39 PM #17 Sharif@Forged SponsorForged Performance iTrader: (92) Joined: Dec 2003 Posts: 13,733 Likes: 1 From: Marietta, GA I don't think there is line of demarcation for "high compression motors". I'd think that anything about 10:1 is higher compression. The VQ motor is not High Compression when compared to many hondas and Porsche's, which have 11:1 and higher ratios. Reply Like Sharif@Forged View Public Profile Visit Sharif@Forged's homepage! Find More Posts by Sharif@Forged View iTrader Profile 03-17-2004 | 01:35 AM #18 350ZPWNZU Registered User Joined: Jan 2004 Posts: 43 Likes: 0 From: California Not really, only some rarley go above 10:, nsx only 10:, type r only has 10: the RSX-S has 11, only the Ferrari 355 F1 has 11, rest are 10 and lil above like 10.8. So yes the VQDE 10.3 is considered high comp. And its a pretty large displacement so its harder. Reply Like 350ZPWNZU View Public Profile Find More Posts by 350ZPWNZU View iTrader Profile Reply Subscribe Related Topics Thread Thread Starter Forum Replies Last Post JMS Racing Twin Turbo VQ35HR MM'08_350Z VQ35HR 225 04-22-2021 10:42 PM FS: 2003 Touring Edition 350z-6MT-2Tone-40K Miles - $14k - NJ ars88 Zs & Gs For Sale 18 04-04-2016 08:52 AM FS: AMS Aluminum Crank Pulley Fixxxercask Engine 6 11-09-2015 12:10 PM Autocross Brake Pads hajwoj Autocross/Road 27 11-01-2015 06:25 PM Tags 2009, 30, 350z, boost, compression, considered, engine, engines, high, life, low, lower, motor, nissan, vq35, vq35de Back to Subforum 2003-2009 Nissan 350Z View Next Unread Nismo CAI Questions! 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