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Discussion Starter #1 (Edited)
Some background: Been slowly chipping away at modding my auto 4th gen since 2004. Got an invite to drag racing and everything progressively spiraled out of control from there. Got the auto 4th gen from running ~16.3 to 15.3 but this was not good enough... The need for speed had me looking for a Crx del sol chassy (non transtop manual) for an H22A transplant but after no luck, a 4th gen manual Prelude caught my eye... A phone call + one plain ticket + a heap of cash later I found myself the owner of manual 4th gen.
Having lead a humble life in stock trim for 250k kms, the time has come for a transformation... In the short term, I am aiming for 13 second passes down the ¼ mile and somewhat more long term I aim to get 200wkw NA out of the H (eventually, after much $$$ and hard hours...lol.).

Current mods (Jan 2013 - April 2021):

Engine accessories:

Custom CAI (2.75" staggered to 4") with 4" Blox velocity stack filter
"Mildly ported" stock intake manifold- 70mm inlet tapering to ~66mm.
70mm Skunk2 Alpha throttle body
Three butterfly plates, one operational, one without valves and one gutted.
Vision ignition leads
Iridium plugs
Blox phenolic intake gasket
D1 Spec FPR
Skunk2 Pro cam gears (6 bolt type)
Jun Stage III cams
Ferrea S10070 Valve Springs (80LBS @ 33; 190LBS @ 23)
Ferrea E11000 Titanium retainers (7degree)
Ferrea K10034 Keepers (7 degree)
Ferrea SL1003 Seat locators
Supertech and Ferrea Valve Stem seals (long story lol).
New Crank Pulley (non-OEM but with harmonic balancer)
Kaizenspeed manual tensioner
Hytech replica header (with a 2.5' collector mod)- 3' outlet
3' header back "custom fabricated" exhaust (no cat, small flexi, two resonators, mandrel bends welded together)
3' inlet mufflers
AEM UEGO wideband
SAFCII
P72 (OBDI) with Neptune basemap road and dyno tuned
ACT clutch with stock flywheel
T2W4 Box
Innovative 75A engine mounts

Body work:
Milano Red paint job (for now)
Lip kit (Value Sport type1 front lip, Mugen Sides, Hiro rears)
Custom Mugen Rear spoiler - Drag spec
Some light to moderate weight reduction
Retro fitted S2000 Seats
TunerView App with tablet display
Carbon fibre bonnet
Honda Access shocks and springs (from the 5th gen- modded to fit) and Mugen shocks and springs
16 x 7 BBS RG rims (& other similar looking rims; with Vitour Tempesta Enzo Drifting Tyres).

Future plans- mainly engine work (2021-20xx):

Parts acquired:

Supertech valve guides
P13 closed deck with balance shaft delete and P5M pistons.
Spare T2W4 tranny in unknown condition...
Synchrotech T2W4 rebuild kit (Carbon)
Cometic head gasket
ARP main and head studs
Gates RPM Racing Timing belt


Parts still required:
Ferrea 6000 series valves
Dry sleeves + 12 to 12.5:1 comp. pistons
ACL (Rod + Mains + Thrust) bearings
Competition Clutch Stage III 2600
Fidanza flywheel

Some pic-highlights below (will be updated over time) and the rest of the thread is as per normal.










 

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Discussion Starter #2 (Edited)
Day 1 of ownership, first photo’s.






Coffee stains anyone




Always a worry, dented heat shield...


Still healthy after 250k kms on the clock


Some maintenance post purchase:
Fixing up the mysterious exhaust leak that sounded amazing




Header is still ok at least...




Cleaned the interior, who knew coffee stains just don't want to wash out...




Rare gem:


Note to self, user manual says no messing with the steering wheel.




For the lolz


What do you do when your Prelude's horn buttons pack a sack (yea so I did exactly what the car manual said not to do.haha):



Note the custom boss kit with stock cruise control switches...


Engine maintenance- replaced severely leaking (and smoking) oil cooler gasket, spark plug and valve cover gaskets, new oil (Valvoline VR1 racing, 10w40), new air filter and new Iridium spark plugs.





Car alarm and getting coasy with all the interior panels stripped.






What to do with the Prelude after general maintenance, get a dyno baseline! Also reallocated the number plate, touched up the valve cover (for now.lol.) and detailed the engine bay (degrease, wash, paint etc).




Unfortunately the mighty H broke the dyno (has nothing to do with the Skyline that was on before the H22A) and I got no readings.lol.

Some stock trim drag time:

In prep for the day, I removed the rear tow bar (solid 20kg of iron.lol) and cleared out all the junk minus spanners, wrench set, some oil, spare wheel & jack and some Dot 4.lol. Installed a relay to give me control over the aircon fan in the cabin (helps keep the bay temps down between runs). Also played with the clutch engagement point. It was engaging right up top, little to no free play... Still engages rather high after 6 full rotations of the master cylinder rod but is much better now.

Aside from the absolutely crap "stock" front tyres, my first and best run of the day was 15.200 at 147.64km/h (4.5k rpm feathered launch).lol. Was amazed that I managed to finish the run in 3rd gear; literally hit the limiter in 3rd just after the 1/4 mile line.haha. All other runs had too much wheel spin on the launch, 60' for them between 2.4-2.5...

RT- 0.368
60'- 2.311
330'- 6.42
1/8- 9.832 @ 114.95km/h
1000'- 12.747
1/4- 15.200 @ 147.64km/h

Began with some easy weight reduction






Water and soap does wonders



Seats for now



Previous owner's ash tray




Dyno done, stock H22A was putting down 117wkw (~158whp) at ~580wnm. Love the 14.1:1 air fuel ratio at 5000rpm, stock JDM P13 ECU...







Had the clutch start slipping on me after the dyno... Will fit an Exedy OEM clutch in the mean time to keep her on the road, still need to fit it though.

Fitted the Hytech replica header and 2.5' exhaust









Fitted a cleaned and slightly ported intake manifold and Blox intake gasket







Stock manifold's IAB runner porting is off somewhat:


Smoothed out this transition:


Removed the stock gasket, took ages!


Intake gasket was a tight fit



New mani on








Ran the engine with the AEM wide band, new intake manifold and hytech exhaust and had a full lean air fuel ratio at idle (greater than 18:1) with stock ECU and stock intake pipe. Removing the vacuum hose off the stock FPR yielded an idle rpm of 13.5:1 ... Sorting out the tune is next on the list, along with a CAI.lol

Next up is fitting the Exedy OEM clutch, CAI, SAFCII, P72 ECU and then some TLC for the engine bay.lol
 

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Discussion Starter #3
Half way through the clutch fitment. Ran into an odd issue with the trans not wanting to bolt back up, could fit three of the mounting bolts but for some odd reason the trans would not shift into place completely...



Discovered the reason for clutch slippage... Clutch was still ~75% new...


Cleaned up a little



New clutch on



So close yet so far... Will remove the clutch and check that the clutch splines actually are correct and that it does slide onto the trans...
 

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Looks like a good start there, did you replace the rear main seal while doing the clutch? Oh, and you probably just need to do some wiggling to get the splins lined up right and get the tranny all the way on, hopefully a liberal does of Honda high temp Urea grease on there as well.

I will say this though, with a P72 and Crome, you have no reason for the SAFC, it is redundant, and will only screw things up for you.
 

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Discussion Starter #5 (Edited)
Looks like a good start there, did you replace the rear main seal while doing the clutch? Oh, and you probably just need to do some wiggling to get the splins lined up right and get the tranny all the way on, hopefully a liberal does of Honda high temp Urea grease on there as well.

I will say this though, with a P72 and Crome, you have no reason for the SAFC, it is redundant, and will only screw things up for you.
No I didn't end up replacing it. After the clutch started to slip I was hoping to do a quick "patch-job clutch swap" over the weekend to have the car drivable for drag racing this Friday :roll:, but after the refitment issue (and hence causing me to miss the drag session due to work all week.lol) I will be taking my time. I have a new main seal to fit and I am really wishing I had the uprated clutch and flywheel on hand already so that I would not have to remove the trans again for a long time.lol. I spent a few solid hours trying to get the trans to mate up. I tried everything including wiggling but there was just something out of alignment, a metal on metal clunk. Clutch was centred in the pressure plate perfectly but the flywheel "looks" like it may be out by a small bit but that could just be parallax! Will have another go over the weekend. I used the Exedy supplied high temp grease which I assume is decent enough?

I guess it varies from tuner to tuner but I found that even after a good Crome road and dyno tune (~3hours worth) there were some loop holes in the tune (very "rich" areas at partial cruizing; partial throttle tuned to disable the narrow band) and the SAFC + AEM wide band could round these spots off (baring in mind that I have a FPR with higher than factory fuel press at the moment). If I retune with the stock FPR the SAFC really will be redundant, aside from rpm display and recall.lol.
 

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To be honest, I have been driving the same Exedy oem clutch for the last 7-8 years, everything from a stock H23A1, to my JDM H22, to my H23Vtec and a 100 shot. It has never skipped a beat yet, even running 1.8 second 60 ft times at the track, since I still haven't really broken my slicks in with the whopping 3 runs they have seen.
 

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looking good. be careful with the mahles. i would recommend darton dry sleeves and your choice of forged piston.

but good luck anyway

Sent from my DROID BIONIC using Tapatalk 2
 

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Discussion Starter #8 (Edited)
To be honest, I have been driving the same Exedy oem clutch for the last 7-8 years, everything from a stock H23A1, to my JDM H22, to my H23Vtec and a 100 shot. It has never skipped a beat yet, even running 1.8 second 60 ft times at the track, since I still haven't really broken my slicks in with the whopping 3 runs they have seen.
That is comforting to hear. I expect the OEM Exedy to last relatively well but I just don’t know how long it will take the punishment for.

looking good. be careful with the mahles. i would recommend darton dry sleeves and your choice of forged piston.

but good luck anyway

Sent from my DROID BIONIC using Tapatalk 2
Yea, the Mahle pistons are a risky/foolish way to go but they suit the budget more so than sleeving at the moment (assuming they don’t fail and write off the cylinder walls that is)... Searches found more “good luck” when using the Mahle’s NA than Turbo at least. I was hoping to get away with a bore, hone and trouble free operation but they may well still bomb out. Worst case scenario the FRM liners and pistons fail, at which point I will need to sleeve a block anyway... All that swayed me towards the Mahle “short cut” was the cost of the sleeves, but I will make the final call on using them once I get quotes for the block prepping for both the "Mahle" and "forged with sleeves" options.
 

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That is comforting to hear. I expect the OEM Exedy to last relatively well but I just don’t know how long it will take the punishment for.


Yea, the Mahle pistons are a risky/foolish way to go but they suit the budget more so than sleeving at the moment (assuming they don’t fail and write off the cylinder walls that is)... Searches found more “good luck” when using the Mahle’s NA than Turbo at least. I was hoping to get away with a bore, hone and trouble free operation but they may well still bomb out. Worst case scenario the FRM liners and pistons fail, at which point I will need to sleeve a block anyway... All that swayed me towards the Mahle “short cut” was the cost of the sleeves, but I will make the final call on using them once I get quotes for the block prepping for both the "Mahle" and "forged with sleeves" options.
the darton dry sleeves are inexpensive. hell i picked some up brand new for 100 on craigslist

Sent from my DROID BIONIC using Tapatalk 2
 

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Yeah, when you llok at the price of Mahles as opposed to other pistons, they will actually probably cost for for the mahles, and the FRM hone process usually costs more to do right, as they have to take a long time to do it right.

For those extra costs, you should be able to do a block with the replacement liners, which will be just fine for NA use. I have seen shops advertise a package with the liners installed for around 300 dollars if I recall correctly.

You don't need to do some monster sleeve setup Like AEBS or Golden Eagle unless you plan to push obscene boost through it, and those jobs are 12-1500 or so.
 

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Discussion Starter #12 (Edited)
Yea, I had a quick browse on ebay and the dry sleeves seem to go for ~$300 which isn’t too bad. Main problem for me is that being located outside the USA ramps up the cost of getting parts. When I priced parts up mid last year the sleeves with a decent set of forged pistons was almost double that of just getting the Mahles (best quote for the Mahles was $700 delivered...).

I have a local shop with the graphite stones required and they have done at least one high hp NA H22A with Mahles with success (~264whp on e85 with Pro 2 cams). No idea of the cost for the FRM prepping but I suspect it probably will be about the same as the getting the sleeves in the end... Given the potential issues with Mahles, I’ll probably just spend a little more in parts and grab dry Darton sleeves with decent forged pistons to avoid future problems. Thanks for the input!

Also, removed the pressure plate and clutch and found the reason for the trans fitment issue. Seems the alignment tool I had isn't good enough (its universal, ~4pieces bolt together) and resulted in the trans not mating perfectly with the flywheel. Could see "fresh" metal in the upper right corner of the flywheel-trans hole, so out by a degree or two.lol
 

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Discussion Starter #14 (Edited)
Clutch job done!!! Painful 2 days but the end product is great. Clutch pressure plate feel is much lighter than the clutch that was removed which is odd. Either way, the clutch grabs and the lude lives!



Seems the crank seal was not leaking, but I replaced it anyhow. I now believe it may have been the leaking valve cover that leaked into the trans case through the timing hole... It was leaking rather badly when I got it.






Crank gasket fitting tool, free from a protein shake container.lol




Gearbox did not wiggle on but got closer than the previous attempt. Made sure the clutch-flywheel alignment was spot on this time. Had to mate the gearbox to the engine using its mounting bolts... No matter what I could not get it to "slide on". Once I had both dowels aligned it would not budge, but after fitting 4 trans bolts and tightening them it slid on.


Sway bar bushes replaced




I also took the opportunity to do a wire tuck, one side is clean, the other is a stock mess.lol.
Before tuck


The final product.




 

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Yeah that looks like it was a good leak back there, if the Valve cover gasket is done and you still have leaks, check the VTEC solenoid gasket. Mine had a tiny crack, and was leaking Royal Purple down my block lol.
 

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Discussion Starter #16 (Edited)
Yea, I think I'll try to replace both the vtec solenoid and dizzy gaskets on the weekend (providing I have some lying around!), I am sure they are both leaking to some degree given the oily mess the gearbox external housing was in...lol.

Will have to consider repeating the gasket replacement process on the other side of the engine when I get around to doing the timing belt and tensioner. Also, considering getting a Kaizenspeed tensioner over the auto tensioner for peace of mind.

Safe to say the clutch is worn in and the car feels much more alive at least. To my amazement the crapy worn front tyres are holding grip in the dry (not sure if thats a bad thing or not.lol.), only break traction when shifting.lol. Engine is crying for a tune however. I tried my P72 Crome basemap tune but it was running at full lean (18:1). Stock ECU is doing for now (think the narrow band is dead, no CEL, just not reading right; idle air fuel is 12-13:1 and ~13.8:1 under WOT...). Hoping to book it in for dyno time and a re-crome tune before getting it down the 1/4mile. Realistically expecting ~14.4 down the 1/4 mile at the moment.lol.
 

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Discussion Starter #17
Master cylinder packed a sack...



Yes, I'll have one of these


Think the Master cylinder was shot before doing the clutch and the new clutch killed it completely. Will keep an eye on the slave but for now its working fine.

Tried the Crome P72, air fuel ratio was crazy lean (tuned with a FRP present). Hence FPR fitted to match the tune.




From stock...


...to hacked.


All soldered up and I have set up a wire loom to allow SAFC plug and play.

Test run



 

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Discussion Starter #18 (Edited)
Ok, so not a great weekend. Photobucket bailed on me, some 10GB bandwidth limit is blocking all image hosting. Seems I will be re-doing all the pics in this thread...

Drag session did not go as planned. First run, 14.9 with no grip in first and side ward "drifting" in second and third upon shifting, like driving in the wet...

Second run I had grip bounce like mad off the launch. Broke off the radiator mounted bonnet/hood stay mount. Also lost my exhaust...lol. Seems I had neglected to fit the bolt that holds the hytech header 4-2 section to the 2-1 part. This vibrated loose on the second run, I hesitated for a brief second and figured meh, she'll be right, and finished with a 15.3 open header...

Slid the 2-1 section back into the header (all fire hot) and then stopped racing for ~40min to fit the bolts required that were behind the passenger seat... In the process my battery drained and I required a push start...lol. Left the strip to charge the battery and returned with a vengeance.lol. Best time was 14.929 at 153.2km/h... Due to grip issues I could not/would not launch above 4k rpm, lost the exhaust from launching at 4.5k rpm... Another odd thing, I saw 7940rpm on the SAFCII recall a few times which is odd, limiter does kick in at ~7700rpm (crome p72).

To make it even better, my cabin video recorder packed a sack, only recorded in 5-8 second bursts. Got two sound clips of a couple of runs from my phone (had no where to place the phone for video) but over all not a great session! Even worse, out of over 1200 professional pictures taken of the event there are none of the prelude! haha

Dial 14.85
RT 0.187
60’ 2.395
330 6.443
1/8 9.764
Kmh 120.43 (74.83mph)
1000 12.563

1/4- 14.929
Kmh 153.2 (95.12mph)






Took the valve cover off for a quick inspection and gave the cover a quick paint strip and touch up.






 

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Discussion Starter #19 (Edited)
Figured it was a good time for a re-dyno :shock:

Was hoping for more gains but I guess I will have to take what I got!

Stock H22A (253k km's on the block):
157whp @ 6800rpm with ~ 600wnm @ 5400rpm

Not so stock H22A (Basic boltons, 253k km's on the block):
177whp @ 7300rpm with ~ 630wnm @ 5400rpm

Net gain of 20whp following:

Custom CAI with Blox velocity stack and filter
Mildly ported intake manifold with phenolic gasket
Vision ignition leads
D1 Spec FPR (fuel pressure ~48psi no vacuum)
Hytech replicas
Custom 2.5" exhaust (no cat, 1 resonator, mandrel but in sections welded together)
New Exedy OEM clutch (no gain expected)
SAFCII, AEM UEGO and Crome tuned P72 (Vtec at 4700, unsure of IAB engagement rpm)
And 17's that are slightly lighter than stock rims with a smaller total circumference (fitted with Toyo T1Rs).











 

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Discussion Starter #20 (Edited)
Got a cheap suspension setup sorted. Got a set of 5th gen Honda Access springs and struts which I threw into the 4th gen. Slightly stiffer and a decent drop from factory suspension at the price of second hand stock suspension. Only catch, the front top caps need to be switched due to the design change on the 5th gen (rears are identical).





Decent difference in design between 5th gen and 4th gen front struts.


Stock mammoth gap



Compress...


...Remove...


...Inspect...


... And done!








There is something about lowered suspension that really changes the Prelude's stance.

 
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