Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 22

Thread: Porting and Polishing

  1. #1
    One of those purists you keep hearing about. sdg3205's Avatar
    Join Date:  May 2011

    Location:  Vancouver, BC

    Posts:    3,300

    My VIN:    thirty two 'o five

    Club(s):   (PNDC)

    Porting and Polishing

    Does anyone by any chance know what the measurable difference is between stock and port and polished heads with aggressive cams? Are we talking 3 hp? 5 hp? 10 hp........ 0.5 hp?!

    Before I go spending the money i like to know its worth it, but i want this to be the first and last time the heads ever come off 3205 so i figure do it once and do it right or don't do it at all.
    Dave

    Here, somewhere.


  2. #2
    Sometimes Owner louielouie2000's Avatar
    Join Date:  May 2011

    Location:  Austin, TX

    Posts:    583

    My VIN:    Pending. Previously 10115 & 5252

    From what Iíve seen, most stock manual transmission DeLoreans make roughly 100hp at the wheels. Most Stage II cars seem to make about 140hp at the wheels. So a 40% bump in power for well under $10k while keeping the car mostly stock looking seems like a pretty decent proposition to me.
    Louie Golden

  3. #3
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

    Posts:    1,960

    My VIN:    01049

    Most of that can be attributed to the cams and the exhaust. On a small displacement motor like this, and without the valve sizes getting modified, porting and polishing isn't going to make a huge difference.
    -Mike
    1981 DeLorean, heads/cams/exhaust, EFI
    1999 Corvette, heads/cam/exhaust, 440 BHP
    2005 Elise, stock
    2016 Chevy Cruze

  4. #4
    Delorean Guru
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    6,193

    My VIN:    10757

    Club(s):   (DMA)

    The heads on the PRV are already pretty good. Not rough iron castings like most American muscle that responds well to porting and polishing. While it can't hurt to port, polish, and gasket match. I don't think it is going to make a noticeable difference. The PRV does respond well to opening up the induction, and exhaust systems. The stock ones are VERY restrictive. More aggressive cams will then make a big difference.
    David Teitelbaum

  5. #5
    Junior Member
    Join Date:  Sep 2017

    Location:  NAPA , CA

    Posts:    12

    My VIN:    10590

    porting and polishing

    from experience you gain 20-60 hp. blending the seats into the ports helps and opening the ports out to the gasket helps. the big question is how much to do this? You can do it yourself like I do and after porting get a valve job. then adding a performance cam will really wake it up. look on you tube for porting videos ,good luck

  6. #6
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

    Posts:    1,960

    My VIN:    01049

    20 - 60? Sure, on an SBC or an LS, but certainly NOT a PRV.
    -Mike
    1981 DeLorean, heads/cams/exhaust, EFI
    1999 Corvette, heads/cam/exhaust, 440 BHP
    2005 Elise, stock
    2016 Chevy Cruze

  7. #7
    Senior Member Christian Dietrich's Avatar
    Join Date:  May 2011

    Location:  Bunker Hill, West Virginia

    Posts:    534

    My VIN:    11035

    My engine in 11035 has the Spec 1 exhaust/no cats mod, larger air box with a K&N filter and CAI tube and a throttle body spacer. Stock heads and cams......... for now and i will say from a seat of your pants feeling, it is definitely a night and day difference over a stock DeLorean and it is much more responsive and the throttle is much more snappier and I have no problem hitting 60mph off the line. I'd say with the mods, that im probably pushing a 25hp gain? It feels it. A good porting and polishing will probably free up between 5 to 7 horsepower it's like Mike said and you polish the seeding real well. I dunno, mabye another 30 hp with cams. I will be really interested to see someone go from a stock engine and have it dynoed then slowly do mods to it from simple bolt ons to full cams and head work to see the gains. Simply getting rid of this cars induction system and exhaust system really does make the PRV engine way better then in stock form. I know I'm loving how my setup is and I have no problem revving my car to redline at times and she pulls very nice. 200hp (engine, not wheels) can be easily done with the right tricks.

    Sent from my SM-N920P using Tapatalk
    Vin 11035 wide stripe, flat hood, 5 speed, Spec 1 exhaust, custom grey/black interior, custom lighting, custom stereo and custom alot of stuff!

  8. #8
    Senior Member Josh's Avatar
    Join Date:  Mar 2013

    Location:  SK, Canada

    Posts:    1,645

    My VIN:    11408

    Club(s):   (TXDMC)

    Quote Originally Posted by Christian Dietrich View Post
    200hp (engine, not wheels) can be easily done with the right tricks.

    200hp out of a 2.8L odd fire PRV with Kjet is not an easy task. Even at the crank.

    You need to consider forced induction. Or get very aggressive with the heads, cams, rebuilding the bottom end for more compression (rods, pistons).

  9. #9
    Senior Member Christian Dietrich's Avatar
    Join Date:  May 2011

    Location:  Bunker Hill, West Virginia

    Posts:    534

    My VIN:    11035

    Quote Originally Posted by Josh View Post
    200hp out of a 2.8L odd fire PRV with Kjet is not an easy task. Even at the crank.

    You need to consider forced induction. Or get very aggressive with the heads, cams, rebuilding the bottom end for more compression (rods, pistons).
    Yeah if you go a little deeper you can but I don't think it's going to be as bad as some think it is and the prv actually responds well to modifications but maybe not as simple as a small block Chevy engine. You might have to get a little bit more aggressive with the heads and maybe even slightly larger valves. I have never really dug too deep in a prv engine but I would love to find one so I can see what I can do with it

    Sent from my SM-N920P using Tapatalk
    Vin 11035 wide stripe, flat hood, 5 speed, Spec 1 exhaust, custom grey/black interior, custom lighting, custom stereo and custom alot of stuff!

  10. #10
    Senior Member Christian Dietrich's Avatar
    Join Date:  May 2011

    Location:  Bunker Hill, West Virginia

    Posts:    534

    My VIN:    11035

    Quote Originally Posted by Christian Dietrich View Post
    Yeah if you go a little deeper you can but I don't think it's going to be as bad as some think it is and the prv actually responds well to modifications but maybe not as simple as a small block Chevy engine. You might have to get a little bit more aggressive with the heads and maybe even slightly larger valves. I have never really dug too deep in a prv engine but I would love to find one so I can see what I can do with it

    Sent from my SM-N920P using Tapatalk
    Naturally aspirated I mean

    Sent from my SM-N920P using Tapatalk
    Vin 11035 wide stripe, flat hood, 5 speed, Spec 1 exhaust, custom grey/black interior, custom lighting, custom stereo and custom alot of stuff!

Page 1 of 3 1 2 3 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •