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Max Boost on Stock Short Block?

Posted by TurboRay, Aug 13, 2019

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  1. TurboRay

    TurboRay Probationary Member

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    Hey guys and gals.....I'm sure this (question at end of post) must've been asked before and I tried searching, but apparently I didn't enter the correct criteria in the search engine. I'm contemplating the construction of a very light street roadster - powered by a 4G63T and a PowerGlide - to compete in NHRA Super Gas.

    I did it a long time ago (3 decades) with a 2500lb home-built BBC Vega, but nowadays the class seems to be primarily populated with $60K Suncoast Corvette Roadsters, $22K Shaffroff 1200-ish horsepower 632-in motors, $6K Mike's Transmission 'Glides, etc., etc., ad nausea.......

    It just makes me wanna throw up every time I see coverage of Super Class racing on "dragracer.tv" or FS1, showing these $100K rigs (cars + towing) blasting off the line for 10ft and immediately stopping the throttle down.....only to "let it go" at about half track so they can fly past the finish line (and, hopefully, the competition) at 160+ mph.

    Anyway, enough ranting! I'm convinced that I can build a very lightweight (1200lbs "minimum" for 4-cyl cars) fiberglass roadster or "Locost 7" with a turbocharged DSM, a "Bill's-Adapted" homebuilt Powerglide (Munroe P/G book) with a 7 or 8-in converter and an 8-in Ford diff.....that will run (are you sitting?) 9-flat, for less than $8K. I would just LUV to stir the pot at some of the nearby (NorCal) Lucas Oil divisional races by running right along side of the V-8 "big dawgs" with a 2.0L 4-cyl engine, LOL..

    Anyway, one of the "keys" to doing such a cheap alternative-car is to use a stock-ish 1G or 2G J/Y 4G63T ($300 @ P-n-P) with a Holset HX35W that I already have, along with bigger inj's, ARP studs and an MS ECU. Sooooo.......after this long diatribe (SORRY), my question is ~ how much boost can the stock pistons, rods and crank take on E85 w/o "ventilating" the block?? Also, what head gasket holds up best.....MLS, copper, or ???. My always-accurate <rolleyes> Power-Speed calculator sez it "only" takes about 400hp to push a 1400lb car to an 8.75 ET with good traction! <eek> TIA!
     
  2. dwdsm

    dwdsm Proven Member

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    You could make your goal with a 6 bolt block, MLS head gaskets, and ARP head studs. Why a HX35 tho? With a modest HP goal of 400 I would think you would be better suited to go smaller and get the max torque curve (although rods may like this less). I'm a little ignorant to setting up a car for drag tho so take that with a grain of salt.
     

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  3. 1990TSIAWDTALON

    1990TSIAWDTALON Moderator

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    Remember, your gonna have to make it STICK on the RWD setup but I would say you throw 35 lbs at it but start out lower on a 6 BOLT block, 2g head setup with the above mentioned parts and a good head/cam setup. Just my 02¢
     

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  4. b00stedtalon2

    b00stedtalon2 Proven Member

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    Make sure it's a 6 bolt so you get the beefy rods. I've pushed a 7 bolt to 44lbs on a 62mm turbo that trapped 146mph (3200lb car). It lived a few years before bending a rod.
     

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  5. TurboRay

    TurboRay Probationary Member

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    THANX for the replies, guys! I've been lurking for awhile, so I'm somewhat familiar with the 6-bolt vs 7-bolt phenomenon. BUT.....as much as I would prefer a 6-bolt motor, the "7's" are far more plentiful in the local J/Y's. P-n-P has a nice search engine for checking inventory within whatever radius you enter from your ZIP. In my neck of the woods (Sacramento area) I found 8 Talons, Lasers &/or Eclipses having 4G63T's scattered among the 5 yards that are within 150 miles from my home. BUT, only one is early enough ('91 Talon TSI) to have a 6-bolt engine, AND it's the farthest away, in Sparks, NV.

    The "other issue" with that Talon is that the photo depicts it w/o any body damage - at least from the angle shown. The etched-in-stone rule of shopping for any major drivetrain component in a J/Y is to find it/them in a severely-CRASHED vehicle......since you then know it was running when junked. OTOH, a "clean"-looking vehicle is probably there due to a FUBAR engine or tranny! Sooooo........it's comforting to know that bOOstedtalon2 was able to stuff 44psi into a stock 7-bolt short block for two years w/o folding the rods &/or ventilating the block!

    I ASSume that amount of boost came in above 3500-ish RPM with a turbo having a relatively-big turbine housing? That much boost "down low" would probably have caused carnage. The HX35W that I already have has been proven to flow enough for roughly 500hp, which is way more power than I need, BUT......Holset's are also generally known to have "light-switch" boost onset. Soooo.....I'm open to other turbo suggestions that will achieve my 400-ish hp goal - especially those that will bolt to a lightly-ported stock twin-scroll manifold.

    For the sake of simplicity and lack of "real estate", I had also hoped to build this combo with (gasp)......no intercooler ~ hoping instead that the ethanol content of E85 would provide enough latent heat of vaporization to sufficiently-offset the increased charge temps associated with 25-30psi - I guess I'll find out. Water injection is another possible option, altho I'm not sure that NHRA allows it. Also.....in keeping with the "cheap SOB" aspect of this build ~ are the stock cams sufficient? What about retarding or advancing either or both of 'em (decent-looking vernier cam sprockets are fairly-cheap on eBay)?
     
    Last edited: Aug 13, 2019
  6. iugrad92turbo

    iugrad92turbo Proven Member

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    Healthy engine known maintenance, good tune some have gone 20 30 psi.
     

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  7. motomattx

    motomattx Proven Member

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    An Evo3 16g turbo would get you to 400hp on E85 and would spool very well, a factory style composite head gasket with Arp studs should seal it well enough for your goal, the head and block surface needs to be checked for square and milled if they aren't well within specs, a flashable ecu or Dsmlink would probably be easier to tune than Megasquirt, King bearings or the like and high zinc motor oil such as Valvoline VR1 would be wise also.
     

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  8. dwdsm

    dwdsm Proven Member

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    Yea I was coming back to say 16G or a slightly bigger option would be a To4e 50trim or FP green mid of the road turbo would do the job and be right in the meat of it's efficiency. You could get those in a BB to increase longevity too.
     

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  9. TurboRay

    TurboRay Probationary Member

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    THANX, Fellas ~ Please excuse my ignorance, BUT......if I'm not mistaken, the E3 (Evo III) manifold(s) and compatible turbos (16G, etc.) that y'all are recommending at least appear to do away with the twin-scroll strategy that I was hoping to retain. OTOH, the OEM E8(??) manifold and compatible turbo(s) definitely have it.

    Soooo.......in keeping with my previously-mentioned cheap-ass SOB strategy, I've seen stock, uncracked, E8 manifolds on eBay for $30-70. Will they bolt up to the stock "early" heads that came on the 6 & 7-bolt motors? If so, I ASSume that I could then install the twin-scroll HX35 that I already have......using one of THESE and a couple of Chinese wastegates. What say y'all??

    BTW ~ what's the difference between the so-called "1G" and "2G" heads that I've read about? Also, does anyone have input on the stock cams that came in the 6 or 7-bolt engines.........at 30-ish psi? If they're "doable" for my goals, should I leave 'em "straight up", spread or tighten the LSA, advance/retard either cam separately, or ???.
     
    Last edited: Aug 14, 2019
  10. 1990TSIAWDTALON

    1990TSIAWDTALON Moderator

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    1g heads have more volume in the runners, 2g have smaller runners but more velocity.
    I run a 1g block 2g head combo on one of my cars and really like it. Car was a high 10 car but on a 60mm turbo.
    My son ran a stock 7 bolt, stock cams, big injectors, Link, twin scroll manifold and a HX35 in a full weight car and ran 11.5 first pass off the trailer at 30-35lbs. Ended up windowing that block, but nothing to do with the drag pass. Took out #4 and left a hole you could see straight thru. Broke the rod at the big end at the crank. Carnage but didn't kill the crank.
     

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  11. TurboRay

    TurboRay Probationary Member

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    Soooo......the only real "downside" of the 7-bolt motors at high boost pressures are the rods? How much do the Eagle(?) H-beam rods cost?

    ADDENDUM: After seeing the pics below of the OEM 7-bolt rods compared to their 6-bolt counterparts......I've become paranoid about using 'em with high boost, in spite of the relatively-good reviews posted by a few members. Soooo.......are THESE any good? The description sounds stellar, but I'm sure they're made "over there" (like so many things today) and I wouldn't have expected to find 4340 H-beam rods with ARP fasteners so cheap! Also, can the pin bores in the factory pistons be cut for floating pins?

    OEM 7-bolt (left) vs 6-bolt 4G63T rods:

    teardown007-jpg.jpg
    teardown010-jpg.jpg
     
    Last edited: Aug 14, 2019
  12. jakelandry

    jakelandry Proven Member

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    I think a lot of people are taking the original question and running a bit far with it.

    Both the 6 bolt and 7 bolt motors in complete stock form less a felpro composite head gasket and head studs can handle any amount of power a hx35 can put out.

    As for my input to the already overgrown advice being posted:

    There are many dirt cheap cams that pick up power without losing anything at all. There is no down side to getting cams unless you want to follow an all stock rule or something.

    Stock rods are fine. H-beams are cheap insurance. 500hp worth of controlled force doesn’t bend stock rods, the several ksi of instantaneous cylinder pressure from running on the ragged edge of knock does that.

    The 2g cylinder head offers many benefits at this power level with minimal drawbacks aside from the fact that a cyclone intake manifold is made for a 1g head. The midrange torque that manifold offers is still absurd even when compared to all the options we have today.

    A lot of the smaller turbos recommended give out too broad of a power band to really be considered ideal in a car that will be living at a high rpm.
     

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  13. TurboRay

    TurboRay Probationary Member

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    Originally posted by jakelandry:
    "There is no down side to getting cams unless you want to follow an all stock rule or something."

    THANX, Jake! I'm not required to follow an "all stock rule".....except for the sake of holding costs to a bare minimum while trying to prove that one can run low 9's in NHRA S/Gas w/o spending $50K-up (also, because I'm a cheap-ass SOB, LOL). The minimum weight for a V8-powered car or truck in S/Gas is 2100lbs - but it's only 1200lbs if running a 4-cyl motor. Soooo......I "only" need 400-ish hp to run 9-teens with a super-light street roadster or "Locost 7" weighing 1600-ish or less, and I'd like to be able to say I did it with a minimally-modded J/Y motor and a take-off Holset turbo.

    I got my "tight" 7-blade/twin-scroll HX35W for $100 from a fellow member on "TurboFord.org" - but I also realize it was an extremely-lucky bargain that shoulda cost $300-500. As stated earlier in this thread, I've located 8 qualifying 4G63T-"donor cars" at local P-n-P yards, using their xlnt search engine......all within a 150-mi radius from my home. According to P-n-P's price schedule, all complete EFI motors are $206 + tax AND a core charge of fitty bux.

    As for my turbo........everything I've read sez it'll flow enough for 500hp, AND it should be fairly responsive in twin-scroll configuration, which I can retain with a used/stock E8 (Evo VIII) cast manifold and an adapter. As for the cams and intake manifold - I was hoping to retain the stock pieces, unless they're deemed inadequate or too restrictive by the "experts" (y'all). :)
     
  14. TurboRay

    TurboRay Probationary Member

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    Any specific suggestions, Jake? :idontknow:
     
  15. jakelandry

    jakelandry Proven Member

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    Just to save you the hassle of searching around here’s a quick and dirty in the cams for our platform:

    Delta cams makes several regrinds. They arc spray stock cams and turn them to new specs. They can duplicate a lot of popular grinds on the market and I’ve heard word they’ll even make a new cam from scratch for pretty cheap. At one point their regrinds went for like $220 but it’s been a few years. These typically require shims under the lifters to get the geometry “right”. Their hks272 is all I have experience with but it was a drastic increase over stock and I’d say the performance per dollar could only be matched by upgrading to a cheap diesel turbo from stock.

    Kelford and gsc are both very popular for these motors also. They’re relatively comparable in both price and performance. They are both of high quality manufacturing with gsc probably being the dimensional winner here. Gsc had a bad production run a long time ago when they were using the same blanks as a few other cam shops. They got unlucky and made some from inferriorly hardened steel which they eventually admitted to after a few broke or got scarred and made their way to the internet. They have since switched to a different billet style of manufacture that seems better in all ways. Both kelford and gsc seem to tailor to people who actually race as their “272” cams are relatively aggressive and really seem to shift the curve to the right more when compared to other 272’s.

    Comp makes a surprising amount of cams for us also but they’re not as clearly marketed as everyone else. They are definitely of high manufacturing quality and well designed but you’ll have to do quite a bit of research to find which ones affect your curve in the way you would like.

    Most of the other cams are either copy grinds, made by comp, or the same cams as the old tried and true his with subtle variations. There’s dks, Brian crower, old school crower, forced performance, maybe some jun laying around, etc.

    Generally speaking, for your power goals and rpm limit, you’d want to stay in the lower tier gsc like the s1 or kelford 264 range. Any cam period will pick up power so it’ll just be where you find the sweet spot you want it. Most anything larger than those will put your power and more in the 6500+ rpm range. For the price, the delta 272’s are hard to beat. They’re somewhere close to the kelford 264’s and gsc s1 with subtle deficiencies. If you care about the uniformity of the lobes and consistency you’ll have to buy the higher priced cams. From the sound of what you’re doing, the deltas would be more than adequate. I’m sure in the past few years they’ve even grabbed up some more of the competitions stuff and duplicated it by now. Give them a call and come update this thread on what they say. I haven’t seen much about them on here in a while.
     

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  16. bastarddsm

    bastarddsm Supporting Vendor

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    Max boost is the wrong question to ask. You should be asking how can i make the most power on a stock shortblock. Boost makes torque, and that hurts parts. Keep the torque down and the rpm up. You need peak power at 8000rpm or so, and with an auto you wont have to take it 10k like a stick shift dsm to keep it on the power. Stock stuff will live better like that.
    If you want to run a stock shortblock heres what I would do.
    1. take it apart and check it over.
    2. clean and ballhone
    3. new npr rings, and ACL race bearings
    4. Kiggly street beehives
    5. kelford 272's or GSC S2's It will make more power with less torque on these over the other 272 grinds.
    6. 2g head and an evo3 intake
    7. HX35 in a .7A/R T3 BEP housing
    8. Small runner header
    9. good fuel C12/C16 something like that. If it rattles at 30psi it's going to break.

    If your car really only weighs 1200lbs it won't take much to run the number.
     

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  17. jakelandry

    jakelandry Proven Member

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    And be mindful that a stock bottom end’s rod bolts at 8k rpm on an auto is a bit risky.
     

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  18. donniekak

    donniekak DSM Wiseman

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    That’s another 6 bolt advantage, bigger rod bolts than a 7 bolt.
     

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  19. TurboRay

    TurboRay Probationary Member

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    WOW, Jake......THANX for the in-depth response! As a result of my long-time experience with 2.3T Ford engines (SVO, Merkur, TurboCoupe) that also use HLA's (hydraulic lash adjusters), I'm familiar with the "geometry" change and resultant maladies that are caused by using a reground cam with smaller-than stock base circles. However, it's been my experience that - in order to restore the stock "tilt" of the rockers, thus avoiding geometry-related probs - it's necessary not only to shim the HLA's.....but also to "lengthen" the valve stems by an equal amount, using lash caps. Regardless, I agree with your assessment of using the HKS "knockoffs" from Delta to achieve my "cheap-ass SOB" goalsl. Delta's cams traditionally seem to offer the best bang-for-the-buck.

    Also......THANX to you, donniekak for the reminder about the smaller/weaker 7-bolt rods. I've seen some some Chinese H-beam rods on eBay for $250-ish ~ PLUS, the commonly-used Eagle and Scat iterations (also Chinese) are only slightly more. BUT.....all of 'em (at least those that I'VE seen) require floating pins ~ meaning that I'd need to "pop" for new pistons as well, thus defeating the "CA-SOB" strategy. OTOH, I've seen several decent sets of "take-out" 6-bolt rod/piston assemblies (w/o "squeaked"/scored pistons) for sale and - since the crank-pin sizes are the same diameter as the 7-bolt versions.....I can't help but wonder if they could simply be swapped in after installing ARP bolts and having the big ends narrowed to the appropriate width (??). Of course, new rings and honed cyl walls would be required......but that would also be necessary with NEW pistons & rods. :idontknow:

    BTW, Donnie........what's are the "other" 6-bolt advantages?? :confused:
     
    Last edited: Aug 22, 2019
  20. bastarddsm

    bastarddsm Supporting Vendor

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    If it comes down to it, a set of eagle rods and decent pistons can be had cheap cheap these days. No reason to trash the dwindling number of blocks....
     

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  21. bastarddsm

    bastarddsm Supporting Vendor

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    You can cut circlip grooves in a stock type piston.......
     

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  22. TurboRay

    TurboRay Probationary Member

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    bastarddsm said: "You can cut circlip grooves in a stock type piston......."

    Are you sure about that, bastarddsm? The pin bores and thus the pins on most "non-floater" pistons are already much shorter than those on yer typical "floater" variety ~ AND......the pin bore and pin length would need to be shortened even further to make room for c-clip grooves. Therefore, I can't imagine that strategy being doable, but......DUNNO.

    Not counting the rings and honing (that would also be needed for new pistons), I'm figuring the cost of used 6B piston/rod assemblies, plus the cost to narrow the big end and install a set of ARP bolts at, say, 200 bux? I suspect that a set of aftermarket pistons and decent Chinese rods would be at least triple that cost......NO?

    BTW, the only reason I'm talkin' about "crutching" a 7B is because of the lack of 1G/6B engines at my local P-n-P J/Y's.......where there are an abundance of complete 7B engines (
    with accessories) for $204.99 + tax + core (49.99) ~ IOW, about 270 bux outta the door!. :idontknow:
     
    Last edited: Aug 22, 2019

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