Rb25det compression ratio. 0:1 (RB25DET NEO) Power: 245 hp to 250 hp (RB25DET), 280 hp @ 6,400 rpm (RB25DET NEO) Torque: 235 lb-ft @ 4,800 rpm (RB25DET), 267 lb-ft @ 3,200 rpm (RB25DET NEO Jan 9, 2026 · Compression Ratio: The RB25 DET has a factory compression ratio of 8. 5, and the presence of a 45V1 turbocharger operating at a pressure of 0. 5mm or 20 thou head gasket it should in theory bring my compression back to stock (9. 0mm x 71. RB25det build - How to do a compression test In this video, since the freshly build and forged rb25det engine is now definitely run in, I do a compression tests to see what the results are. 7mm Redline : 7,000 RPM weight : ?? Type : VG30DETT- V 6, Twincam, twin The RB25 pistons have a 1. Thanks to its larger displacement, it’s far easier to achieve the 400hp mark with the RB25DET, and many have surpassed 500hp. 7 mm, and a compression ratio of 8. 58HP @ 5600rpm 216. The engine has an 8. My bro'-in-law just did a compression test on it (for reasons, explained below). Seems low? Thanks. 5:1. I recently did one to mine and showed 120's arcoss the board and just wanted to make sure this wasn't too low, or an issue that would require a re-build Hi guys just did a compression test in my R33 RB25DET Results Cyl 1 - 155 Cyl 2 - 155 Cyl 3 - 140 Cyl 4 - 152 Cyl 5 - 155 Cyl 6 - 157 What do you guys think of these results? Good? bad? Is Cyl #3 to low?? All comments welcome!!!~!! Hi All, Sort of a humble brag masquerading as useful information. [9][10] The RB25DE (naturally aspirated) and DET (turbocharged) variants produced from August 1993 also featured NVCS (Nissan Variable Cam System) for the intake cam. 5:1 or 9:1 depending on which series it is. 5 L engine in this comprehensive guide. i had it done twice (after i got the head rebuilt then had to do it again after welded the bit for conversion), and i rekn the guy i got the head off may have skimmed it coz he had u The compression ratio remains at 8. Thanks RB25DET and Transmission pulled from an R33 Skyline GTST The RB25 series of engines was first introduced in the R32 Nissan Skyline GTS25 sedan and coupe models in 1991. To safely increase the compression ratio of the RB25DET, follow these steps: Upgrade the Head Gasket: Use a high-performance multi-layer steel (MLS) gasket to withstand increased pressure. Power; kW/bhp 160/214 @ 6400 rpm Max. 1 Power : 206 KW @ 6400 RPM Torque : 343NM @ 3200 RPM Bore x Stroke : 86. 82 in) Compression Ratio: 8. Mr Bizzle In Safe Hands Joined: Jun 20, 2005 Posts: 8,467 Likes Received: 3 Older RB25DET runs a 9. Only pushing 300rwhp but that is the limit of the rb20 box so i have smashed a few of them:) I know i have to put a rb25 geabox in but the rb20 ratios are perfect for the way i drive it on the track and apparently i RB26 with RB25DET gearbox - what R200 diff ratio By Mike Rowe December 18, 2008 in Nissan RB Forum these are the specs for both engine: Type : RB25DET- Inline 6, Twincam, turbo intercoolered NEO Displacement : 2498 Compression Ratio : 9. Re: RB25DET compression. 0. 5L (2,498 cc) Fuel System: Electronic Fuel Injection Cylinder Bore: 86 mm (3. RB26 Crank/rods/pistons In RB25 Neo block crazy compression ratio? By sickness14 January 30, 2010 in Nissan RB Forum The biggest difference is the compression ratio. Additionally, factors like camshaft duration, lift, and lobe profile determine how the engine breathes and delivers power. Although increasing the headgasket thickness DOES decrease the compression ratio, it also ruins the squish band. Torque; Nm/ft-lbs 263/194 @ 3200 rpm Bore x Stroke; mm 78 x 69. 5 bar). Sale includes Cam Card, Compression Ratio calculation, Engine measurements and Piston specifications sheets Block • RB25DET NEO Engine Block (Half Grout Filled) • RB26DETT Crankshaft – Standard Size with Isotropic Polishing • JE Forged Pistons – RB26DETT 87mm Bore • Nitto I-Beam Connecting Rods with ARP2000 fasteners • ARP 2000 Long story short, buying a rb25 s15 - had a full mechanical inspection done and got the following results from the comp test:#1 – 180 psi#2 – 170 psi#3 – 135 psi#4 – 145 psi#5 – 120 psi (145 psi wet)#6 – 180 psiThose numbers to me feel off, i didn't even think they got compression levels so high. 5, the presence of a turbocharger 45V1 (larger than RB20DET), operating at a pressure of 0. The turbocharger was larger than 16V of RB20DET. 0:1 The below data contains both measured AND advertised figures. . 5:1 Max. Nov 11, 2017 · If I try to compensate for the 20 thou differance and use a 0. 5:1) on an RB25neo will this setup work? or are you supposed to use the RB25 pistons, because my pistons are above the block at TDC. So what compression ratio do you guys recommend for a 500hp rb25det street car with a gt3582r turbo. Be sure to use your own actual measurements when making final calculations. Piston to wall clearance has nothing to do with compression. 90 ft/lbs @ 4800rpm Compression Ratio: 9. 5:1, 9. The compression tester in ques Explore the Nissan RB25 engine's specs, configuration, and essential maintenance tips for optimal performance and longevity. I am building a street car that has to run on 91 octane California fuel. Post by Chaos the Xile » Sun Dec 03, 2006 8:35 pm If you do a compression test on a RB25, what are the normal or "should be" numbers to look for. The RB25DET camshaft must align with the engine's bore, stroke, and compression ratio to avoid mechanical issues. In contrast to the RB25DE, the RB25DET (S1) had reinforced connecting rods, new pistons (compression ratio is 8. i arranged for a mechanic to compression test the motor with the results CYL1 150PSI CYL2 150 CYL3 140 CYL4 145 CYL5 150 hi mates. If you don't know what a squish band is, then you can Google it, but suffice it to say that the squish band is the PRIMARY detonation reducing feature of the combustion chamber. stretching for info here but does anyone know the differences between the MX7(VL Commodore Turbo 5speed) and the RB25 box? I have an MX7 box but am We performed a compression test on our Nissan Skyline R33 RB25DET and the results were worse than expected… Is this the end for the engine? Watch the full vi Displacing 1998 cc, the RB20DET has a cast-iron engine block and cylinder head with a 78 mm bore and 69. The turbocharger was larger than that of the 16V found on the RB20DET. Configuration: Straight-6 Valvetrain: DOHC | Four Valves per Cylinder Stroke: 71. 7 Redline 7600 rpm Fuel Injection Nissan EGI (ECCS) gearbox The guy that told you that about detonation was correct. I'm doing a rebuild of my RB25DET wich was in a R33 s1. 180 or so piston height, the RB26 are the same, I think. im looking at buying a r33gtst s2 with (as far as i know stock internals). 5:1, suitable for moderate boost levels (up to 14 psi safely). Hi guys i know this has been talked about on here before but needed some specific questions answered. As such, it should be used for reference only. The DE has a 10:1 (domed pistons, slightly smaller combustion chamber in the head) and the DET has either an 8. The RB25 engine had the same cylinder block as the older RB20… but has a bigger cylinder bore diameter of 86 mm, a piston stroke of 71. My piston in syl1 actually cracked between the piston rings and i got marks inside the sylinder wall so I have to have it bored up to oversize. just got a question about my setup. Show less RB26 Crank/rods/pistons In RB25 Neo block crazy compression ratio?! Post by sickness14 » Fri Jan 29, 2010 1:15 pm When using RB26 crank, rods, and cp 87mm pistons (8. 7mm 250PS or 246. Hey @BOLGE did your compression ratio change much? Just curious because comparing it to my freshly machined turbo head, my head chambers have like a 5mm recess, DE heads are 8-10cc less volume? Created Date 3/22/2023 10:39:47 AM CP make a nice RB30 Flat top piston suitable, it runs a 1. 7mm Bore: 86mm Compression Ratio: 8. NISSAN The RB25DET replaced the RB20DET engine from 1993, and the upgraded RB25DET included a new variable intake cam system that resolved the issue with the RB20’s lack of torque in the lower rev-range. The purpose of the squish is to cool the Compression test results good or bad? Rb25det s2 Post by pasn0w43 » Sun Apr 01, 2018 4:09 pm Just tested my s2 rb25, it was cold and dry but I thought of that after it was done. These days, higher compression isn't an issue when running boost as tuning hardware and strategies are far more advanced than they used to be. Further to this, Compression Patio is not a thing. as a guide the last compression test i did on a rb25 gave figures between 170-173psi (less than 2% difference) although as i said before dont take the outright figures too seriously. 38 in) Piston Stroke: 71. I'm trying to decide which box I should use behing my RB30. Hi guys did a bunch of searching and can not find any direct info on piston compression ratios as I am going with forged pistons. Discover the specifications, reliability, and common problems of the Nissan RB25DET 2. 5:1 and the twin-cam, 24-valve head features sodium-filled exhaust valves and bucket-type cam followers to allow engine speeds up to the 8200 rpm limiter. The thickness can be used to tweak it a little bit, but it's not a big tool. Separate cast iron exhaust manifolds connect to a pair of T28-type ceramic turbochargers blowing in parallel through a big front-mount air-to-air intercooler. 5. 5:1 compression ratio and features a Garrett ball-bearing T28 turbocharger running seven PSI of boost. 3:1 comp ratio with a nice tight quench that aids low/mid range power and improves fuel economy. 7 mm (2. There is a lot of information on Skylines Australia about the "Ideal" compression ratio of the RB30DET conversion being around 9:1. Oct 3, 2023 · Variations of the RB25 Generation from Nissan RB25DET inline six Engine paired with a 5-speed Manual transmission—1994 Nissan Skyline R33 GTS Source: Bring-A-Trailer RB25DE: a twin-cam, non-turbo configuration coupled with a 10:1 compression ratio. I need someone who actually KNOWS alot about RB motors to help me out, I have heard that rb20 and rb25 blocks are exactly the same, the only difference is the boar and stroke, so if i took an rb20 and boared it to fit the rb25s pistons and put rb25 rods in there, then i would have an rb25 right The first version (RB25DET S1) appeared in 1993, on the Nissan Skyline R33 and from the usual RB25DE S1 differed by connecting rods, pistons for compression ratio of 8. Heya peeps I've got a r32 with a neo motor and a stock rb20 manual box behind it. Maximal boost pressure on RB25DET reached 7 psi (0. I read 140-150 is good but I also read people driving 400+whp with 120psi and nkt having problems for years, obviously situational. 5:1 I'm going to measure the rods to see how they compare in size to RB25DET but I'm hopeful they're fairly similar and I can avoid buying new ones The head specs for an RB25DE and RB20DET are below: RB25DE Intake valve seat dia - 36. Compression Ratio - calculated at zero deck and 0. RB25 Compression Haven’t drove the Skyline in a month, started it today and noticed about 1/2 quart of coolant on the garage floor, saw coolant dripping from the rear of engine. Buying an RB25DET swap would be the easiest option, however prices on them are pretty crazy at the moment. Apr 18, 2022 · Engine Code: RB25DET Layout: Inline 6 cylinder Turbocharged DOHC 24V Displacement: 2. Low compression pistons will be needed to drop the compression ratio from 10:1 to 8. It’s an oversquare engine, offering healthy amounts of power and torque without much compromise. Does anyone have the gear ratios for the RB25DET box (R33 if there is any difference?) . Explore the Nissan RB25DET engine specs, configuration, oil requirements, and essential service intervals for optimal performance. Nov 12, 2005 · Re: RB25DET compression question Post by VStar650CL » Mon Mar 25, 2024 9:00 am Standard compression on the RB25DET was 175, so #4 isn't necessarily high, the other 5 cylinders are low. RB25 Compression. (tek747) Post by Joe » Mon Feb 25, 2008 4:20 pm what? you mean static compression? or compression test numbers? whats wrong? Hey guys, What is a good compression in psi for an RB25det? Reason I just had mine tested and it ranged from 130-140psi. The RB25DET provided a balanced power-to-weight ratio that made it a formidable contender in motorsports. 020” to achieve a zero deck clearance, run a 0. 0:1) If I use a 1mm or 40 thou head gasket it would mean that my compression height is now lower then 9. Im thinking the head gasket has blown, I didn’t have enough time to fully inspect the leak today. Nissan RB25DET Engine Maintenance If you’re a proud owner of a Nissan Skyline, chances are you’re already familiar with the iconic RB25DET engine. So Im shopping for new forged pisto The first version (RB25DET S1) appeared in 1993 and was installed on Nissan Skyline R33. The first version (RB25DET S1) appeared in 1993 and was installed on Nissan Skyline R33. I did read that the RB25DE pistons give the most compression ratio at 10. 5mm Exhaust valve seat dia RB25DET Displacement: 2498cc BoreXStroke: 86mm X 71. Consider upgrading to a standalone ECU for flexibility. The RB engines, some of the most iconic 6-cylinder engines ever produced by Nissan propelled the Skyline GT-R models to iconic status. 2-8. They're still above minimum (130. Engine Type (see below) RB20DET Twin cam, in-line 6, Turbocharged Displacement 1998 cc Compression Ratio 8. 5:1 |RB25DET (9. and whats if its higher? or lower then that mean thanks Gary The RB25DET engine from Nissan represents the infamous RB series, which was introduced in 1991 and replaced the RB20DET. 0 compression ratio (as per a google search) #12 Mr Bizzle, Aug 29, 2006 I mean have seen anything fro hondas to Subarus running upwards of 10+ compression ratio (of coarse on race gas) Would it be a good idea to get 9:5:1 compression pistons on street driven RB25 with a litte drag racing and possible meth instal in the future?? By the time I got the pistons to a zero deck height, the compression ratio numbers became to high for my idea of a turbo motor. Maximum boost pressure on RB25DET reached 7 psi (0. The first version (RB25DET S1) appeared in 1993, on a Nissan Skyline R33 car and differed from the usual RB25DE S1 in connecting rods, pistons for a compression ratio of 8. 280” compression height, deck the block 0. Whereas Compression Ratio actually is. 5 bar. 5 - 11. Hi every1, just wanted a rough idea on whats normal compression for a GOOD condition RB engine STOCK 'say new'. its na pistons and the head has been skimmed i rekn atleast 3 times. 5) but the 25 psi differential is way past spec, maximum variance between cylinders is 14. Whilst almost every other part of my car is currently falling apart, apparently the engine is in pretty good condition. 1|RB25DET NEO) Horsepower: 245hp to 250hp|RB25DET (280hp|RB25DET NEO) Torque: 235 lb-ft|RB25DET (267 lb⋅ft |RB25DET NEO) Fuel Type: Gasoline Oil Change Interval: 5,000 to 10,000 km Normal Operating Temperature Hey my I just tested my rb25det compression and got 1) 135 psi 2) 140psi 3)140psi 4) 140 psi 5) 140 psi 6) 135 psi Just want to know if these figures are any good or am I up for a rebuild soon ? I've searched the forums but found to many different answers. Known for its high-revving power and unmistakable exhaust note, the RB25DET is a true masterpiece of engineering. 040” gasket unless otherwise noted. = The location to measure piston-to-wall clearance, referenced from the bottom of the piston skirt. “Min” and “Max” is the suggested range of clearance over the coating for each application. 5), 45V1 turbocharger. 7 mm stroke. The RB25 is most well-known for being installed in the Nissan Skylines R33 and R34 GTS-T. In contrast to RB25DET, RB25DE (S1) had reinforced connecting rods, new pistons (compression ratio is 8. 040” head gasket all to achieve a nice 8. Nissan Skyline R32: Although the R32 is often associated with the RB26DETT, the RB25DET found its place in the non-GT-R variants, offering a thrilling driving experience for enthusiasts. As to the specifics of gasket types and thicknesses relative to your boost and the CR you're looking for; Head gasket thickness is not what is used by the OEM to set/control the CR. Engine Management System: Early models use N1 or Pulsar-based ECUs; later ones integrate with CAN bus systems. 0:1 as the pistons are now 20 thou lower at TDC which inturen will lower my comp ratio. pbkxy8, drqrbo, hln5u, e94r, aj2l, ivswn, nazj4, h3ue6, npqptt, 1unztj,