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From turbo to second dyno day



blog-0359863001438562788.jpgMany of you will have seen an abridged version of this on the 2002 group on Facebook, so apologies for the repetition.

After taking the car to the dyno once the EFI build was finished, I kind of got the bug for more power which is probably no surprise to anyone here. I was somewhat disappointed in the 134rwhp/129tq on ITBs+EFI, and figuring that another dyno session with no substantial changes would only yield modest gains, I decided to stretch myself and go forced induction.

I looked for a bolt-on solution and came to the conclusion that the Century/BAE turbo or DA/Camden supercharger kits out (if I could find one) are several generations behind today’s forced induction technology, and I would likely be more satisfied piecing something together myself. Hey, if I can do EFI myself, turbocharging can’t be that hard - right?

Also, I was/am too emotionally and financially invested to my ITBs to ditch them. It would have been easier to go for a true turbo plenum with single throttle body setup, but that would meant $ wasted on the ITBs. Later in this thread, you might be tempted to think I over-plan, but I refer you back to this part where I went straight for sexy ITBs for my EFI build without considering what I might want to do next.

I compartmentalized the project into discrete, sequential chunks and only purchased the parts necessary to complete that specific chunk. Failure to complete one chunk of work would halt the entire project, but planning always involved at least two chunks ahead. Once I committed to going FI, it was difficult to not immediately splurge on a honking great big turbo. But I know the turbo would only have turned into an object d’art on my mantlepiece if I didn’t plan properly.



  1. pressurized intake
  2. intercooler location
  3. exhaust manifold
  4. coil relocation/upgrade
  5. turbo positioning
  6. plumbing
  7. dyno tuning


I had already decided that it was going to be a “no cut” build meaning no bodywork incisions for routing plumbing of any kind. Couple of reasons:

  • my engine bay had been refreshed just prior to my purchase so looked pretty spiffy without me hacking holes in it
  • I haven’t attempted any body work of any description yet so cutting, welding and any major fabrication is out of scope for now
  • I wanted to either be able to return it to “stock” if desired, or leave that to be a mostly easy choice for the next owner


Phase 1

When I converted to ITBs I had issues with the alternator and clearance for the air filter (see previous blog posts). I surmised I would have the same issue mounting an intake plenum (except that it is not a true plenum) so set about moving the alternator from the traditional 1602/2002 location to that found on 2002Tiis. I wrote that up in a separate post but here it is again for completeness:


I need to make some room up near the inlet manifold by moving the alternator. I saw some posts talking about using the later Tii brackets on a regular 02, but never saw "a recipe" posted, so here is mine. Note that the alternator pictured is a 90A unit from BNR (eBay) with a built in voltage regulator. I don't know whether using an external VR makes this easier or harder as I never tried.


Parts needed:

  • 1x Tii alternator bracket (part # 11141257413)
  • 1x Tii alternator support bracket (part #12311256082)
  • 1x M8 1.25x100mm bolt
  • 1x M8 1.25x90mm bolt
  • 3x Round Spacer, Aluminum, Plain Finish, 5/16" Screw Size, 3/4" OD, 0.315" ID, 3/4" Length
  • 1x XPZ962 (or XPZ0962) v-belt/fan belt from Gates, Goodyear, Contitech, etc.
  • Various other M8 bolts, washers and bushings from your existing alternator bracketry


The round spacers are used to pad the gaps between various components. Re-use your existing bushings and fit them to the new Tii alternator support bracket. You may need to lengthen the wire between your starter and your alternator as mine was only just long enough with the alternator in the new location.


The 90mm bolt which the support bracket attaches to also secures the front timing cover to the block. Best to leave the bolt a little loose, get the alternator into position and secured, and then torque that bolt down last all the while ensuring that it is indeed pressing the timing cover to the block tightly. Use washers between the spacer and timing cover if you need to shim it to you liking, or thinner spacers - whatever your car needs.


See the following thumbnails for detailed pics.






After all that research, I had to move the alternator back to the original position! Read on.


My girlfriend must have thought I was going slightly mad at this point. You know how it is. You obsess over a part (probably one with a large price tag) for weeks, by constantly revisiting the same web pages over and over, comparing specs, but never making a purchase. Lists are drawn up, measurements are taken, and drawings are made. I was like this about the plenum or air intake.


I needed something that would bolt onto my ITBs. I really wanted a sexy carbon fibre one from Reverie Ltd, or the aluminium one from Jenvey, but repeated measurement and kindergarten quality cardboard mockups suggested they would be too big for the space available. Here is where I polled the assembled FAQ brain trust with little success for other ideas. I am surprised no one suggested just going with a E21 or E30 EFI intake system.



After some unsatisfactory communication with Dbilas in Germany I finally ordered their “airbox” designed for Ford Focus and VW 16v ABF engines. Like my EFI air filter, I used silicone hose and t-bolt clamps to mount the plenum on the face of the ITBs. It looks amateurish with all the bolt threads sticking out everywhere, but I am an amateur. Maybe I will revise this mounting in the future for a cleaner look.



My MAT sensor was mounted to the backplate of the air filter on my EFI build so I had to find another location for it. And turbo builds need a fast acting MAT, so I had to purchase a new Bosch open element type. With the new plenum being aluminium, it was easy to drill two appropriately sized holes (one for sensor element, one for bolt securing sensor to plenum) and tap one of them. Hmmm… boost leaks… I should check if those holes air air tight at 18psi...



Phase 2

This is where I discovered that I wasted time relocating the alternator. I did the parts obsessing thing again over intercoolers. For simplicity (avoid plumbing needed for water to air) I wanted an air to air intercooler but I couldn’t find an off the shelf one that was the right dimensions. I would either have had to cut body work (i.e., “gut the nose” of the car) or place the IC on the outside of the car and run piping to it. So, I went for a small heat exchanger and coolant pump behind the grill, and a water to air intercooler in the engine bay. I already had a Spal electric pusher fan mounted in the nose, but I had removed the wiring long ago always meaning to recommission it at some point - it’s a tight fit up there!


The IC stands vertically in the engine bay roughly where the battery once would have been. Many many hours of browsing on plumbing, aquatic and hydroponic sites got me a rudimentary cooling system. I also tapped that IC cooling system to supply the turbo with coolant. I used the radiator filler neck from a sports bike mounted on the inner drivers fender for a remote filler neck for the IC and turbo cooling system. The heat exchanger is a 19-row engine/oil cooler, and the pump is a supercharger Bosch coolant pump used on Mercedes and some Mustangs.






Also shown below is the first and second iterations of the intercooler hoses which were first just hoses and clamps, and looked terrible. I switched to AN fittings for a much cleaner look. Filler cap is from a motorcycle.




Phase 3

I had read a lot about exhaust manifolds at this point. I could go with an ebay special, flip a stock manifold and have an adapter made, look for an old Century/BAE part, or commission one from the various custom guys out there. The more reading I did about the custom ones, the more I thought that the relative expense involved was no guarantee of avoiding manifold failure. I went for a cheap ebay manifold and almost immediately regretted my decision. “Fits 1000x better than the other manifolds” the vendor claims on their ebay ads. If that is true, the “other manifolds” must just simply not fit at all. The holes on the exhaust port flange on the one I purchased needed to be elongated by a good 5mm in places just to get it to fit over the exhaust studs. Anyway, an evening spent removing metal and destroying a drill bit set fixed that. Apparently I was so annoyed by the manifold I didn't take any clear pics of it, but here it is with the header it replaced.



The turbo flange on the manifold was a T3 pattern and I already knew I was going to be purchasing a T25 flanged turbo, but I had already scoped out a T3/T25 adapter… on ebay. You already know where this is headed...


Anyway, phase 3 complete and, from more mockups and measurements, it looked like the little turbo I had in mind (but not yet purchased) would fit without me having cut anything to run intake pipe.


Phase 4

As you may have read, I converted to a coil on plug setup using coils from early 2000’s VW/Audis. It worked really well once I found the right version of the coils, and looked cool in a “that’s unique” kind of way. With the exhaust manifold in place I could see those COPs were no longer going to fit as they stuck out proud of the head a good three inches (reminder: it looked “unique”) and fouled the manifold. My interest had already been sufficiently piqued by reading about the D585/LS2/Yukon coil-near-plug coils on the megasquirt forums that I had purchased four of them, so that’s the route I took.


Not being a fabricator myself, I again turned to my favourite vendor for help. ebay turned up several suppliers who were producing crude brackets for mounting these coils in muscle car conversions, so I bought a set. Being for muscle cars, I got two brackets, with each bracket holding four coils for V8 engines. One bracket is now for sale :)


I found a spot under the exhaust manifold with enough space to mount the coils in the bracket using some universal bendable aluminium brackets left over from mounting a fan. I made up some custom 8mm (Taylor? MSD?) spark plug wires with proper D585 boots. Heat is going to be a concern in this area, so I slipped heat reflective sheathing over as much of the plug wires as I could. I may still have to install some kind of barrier to protect the coils, but I cannot sheath them like the wires as they need cooling too.

The old coils:




The new coils as they arrived (glad I kept them for a few years after I didn't used them and went COP instead):



The new coils:









Phase 5

After another sub-optimal vendor experience (they would not sell me a part unless I discussed it with them in person or by phone. Email was not, in their eyes, a suitable communication medium for this type of consultation despite 99% of my professional communications being via email), I purchased a GT2560R water cooled turbo with a 5-bolt turbine exhaust flange/T25 turbine inlet flange. The ebay special T3/T25 flange adapter was too tall. The turbo compressor housing hit the inner passenger fender and would not mate with the adapter flange. Bugger.

First adapter too tall:


Bits and bobs:




The original adapter didn’t have enough meat on the flanges for it to be machined shorter so back to trawling the interwebs. Found a guy down south who produces all kinds of turbo flange adapters to order including a snazzy T3/T25 one. Purchase made.


F-you, USPS! The new adapter arrived. I was all excited. Oh. Shipping box split open. Only half the adapter present. More hassle, another week wasted getting a replacement, but the vendor was cool and USPS coughed up the insurance.





Second adapter once all the bits are together, plus a height comparison with the first adapter:




The second adapter fitted perfectly with more 1cm clearance between the turbo and inner fender, and more test fittings followed to figure out routing of oil and coolant lines before committing to thread locker.


Another learning moment for me: a T25 5-bolt flange is different to a GT25 5-bolt flange, and an adapter for the former will not fit on the latter without modification. If anyone needs a T25 5-bolt to 3” v-band exhaust adapter….



By now I had all the major system components in place and it was a case of “stringing” them together.


Phase 6

Lots of random stuff in this phase. I needed to run wiring, relays, fuses and switches for the intercooler pump and fan. To do this, I expanded the fuse/relay blocks I had installed for MegaSquirt under the rear seat, and purchased two switches for manually operating the pump and fan. The switches are ‘02 pull switches… for electric choke maybe? I had been running with no center console for years (I like the uncluttered look, and who needs a radio with ITBs?!) so fitted one and got the radio working again. The pull switches are located either side of the ashtray on the console fascia.


I have temporarily mounted a VDO Vision vacuum/boost gauge in a bracket hanging under the dash. It’s in a perfect position to NOT be able to see it while driving. I will have to figure out a more permanent and more visible solution, perhaps involving the center console again. Emails to Parker Performance to that end went unanswered after an initial response.


Before without the console:




Console fitted with boost gauge (will I ever mount it properly?) and pull switches:





I knew enough not to purchase a “complete universal turbo kit” off ebay, or even one described as being for an M10/’02, but I did succumb to a universal 2.5” piping kit and immediately spent the same amount all over again on specific pieces to finish the job. Lots of 2.5” pipe left over if anyone is interested. See a theme here?


The air filter sits on the “cold” side of the engine bay and runs up over the radiator (not ideal) to the compressor inlet. The compressor outlet is routed down the inner fender and under the engine roughly inline with the bottom of the oil pan, and then turns vertically to connect to the vertical intercooler. Exhaust is routed via a 3” stainless pipe, with o2 sensor mounted on it, that connects via a downpipe and reducer to a 2.5” IE stainless exhaust.

The BOV is located on the piping under the engine, tucked up by the coils. I messed up the BOV spring selection and got one way stiffer than I needed. I knew I needed to know vacuum at idle instead of boost PSI, but as the car was not running I couldn’t tell what inHg it pulled so googled, guess and got it wrong. Another duplicate purchase.


A local one-man-band exhaust shop fabricated the downpipe and made the join to the existing exhaust. I had planned to tow it to him on a U-Haul dolly, drop it off and pick it up, but my German SUV tow rig had other ideas. U-haul said my trailer light module was kaput and refused to rent me the dolly. So, the night before the (long awaited) exhaust appointment, I had to rapidly get some outstanding issues resolved so the car was able to move under it’s own momentum. I gingerly drove it (you know the feeling) the two miles or so to the shop, hazards flashing, in the ditch, with a sign attached to hopefully placate any passing police. Nothing burst into flames but it’s loud with an open pipe. And that turbine whines like a MFer with an open pipe. Made it to the shop with the smell of newly heated fresh components permeating the cabin. Only stopped twice to look for flames!









The manual boost controller is mounted (in)conveniently to the compressor housing via a bracket. I will need to relocate it due to potential heat problems and it’s damn difficult to access in its current location. Purchased and installed a vacuum manifold, then tidily as possible ran lines to MAP sensor (I was only running an AN tune before), boost gauge and BOV. Switched out the 29lb/hr fuel injectors for some 60lb’ers which is probably overkill, but drivability doesn’t seem to have suffered. Had a leak from one of the injectors that was not seated properly and the dire warnings of petrol leaking at 43psi were immediately foremost in my mind. Easy fix though.



Cooling and oiling the turbo was a real pain. Someone had previously galled the threads on the oil pressure sensor port on the distributor house, so I had to wrap plumbing tape (I know, I know… I am shamed) around the threads of an adapter I bought to fit in that port. Leak stopped, but it bugs me knowing there is a stripped thread waiting for me or, worse, the next owner. The adapter relocates the oil pressure sensor and provides an NTP port for “expansion”, in this case the oil feed to the turbo. Oil return was a bitch too. I eventually drilled and tapped a hole in the front timing cover after much deliberation. Not wanting to have a soft porous hose after a few months use, I searched high and low for hose suitable for the oil return before finding something somewhere with the right specs.




Cooling systems are simple right? Closed system, pump, blah, blah - that’s it. No air locks. The turbo coolant inlet is at about the same height as the coolant filler neck, and the coolant supply hose runs ever so slightly uphill meaning an air pocket is trapped where it is least welcome - at the turbo housing. With much rocking of the car, squeezing of hoses, and jacking the car up at acute angles (oh, the neighbourhood car guys loved that sight) I could get the air out, but I knew at some point I would have to drain/refill the system and didn’t want that hassle again. I place a fitting in-line in the coolant supply hose that allows me to unscrew a port at the highest point in the system (besides the filler neck) to bleed off air that otherwise would be trapped.



One thing I never fully addressed in my MegaSquirt build was driving the stock tachometer. Tried every home brewed remedy out there I could find - diodes, resistors, lucky rabbits feet and four leafed clover of various specs soldered together but none of them worked with my COP set up. North Hollywood Speedo agreed to convert my existing tach to work with the MegaSquirt output. It was partially successful. Yes, my tach needle moves, but only in some vague approximation of the true RPM value. I call it my lazy tach. It bugs me.





Phase 7

Before I got it all buttoned up, I made an appointment with Shane at DB Performance in Rogers, MN to do the tuning on their dyno. They did the EFI tune for me and were great to work with. There were still lots of things to straighten out before dyno day #2 like getting it to run on a basic speed density tune. Even on the basic tune I could tell power was up!

I didn't bother with a tow dolly this time and drove to the dyno. Discussed my goals with Shane: reliable 200rwhp, max 13PSI (stock internal, stock head gasket), street drivability. She got strapped in and I just hung around feeling useless.



The results were disappointing. 175rwhp and 172tq.




You can see that the PSI line in the graph above tapers off. Shane called me over after a few hours to discuss the problem, it wouldn't hold boost. We went over several causes (exhaust too restrictive, etc.). I volunteered up "boost leaks?". Shane asked "You did check for boost leaks, right?". Sheepishly, I did not. We pressurized the intake and listened to many, many leaks noisily discharge precious boost. His next customer was already outside and I wasn't about to be making gaskets out of my underpants at $150/hour still strapped to the dyno, so we called it quits for the day. Leaks I found:

  • Throttle bodies to intake manifold
  • Shorty, straight air horns to throttle bodies
  • Vacuum hose
  • Silicone coupling hose
  • Throttle body shaft seals


I have fixed all the leaks but the ITB shaft seals. Another reason I should have ditched the ITBs.


I also had a slight hesitation when building boost on hard acceleration. I rectified that by regapping the plugs down from 0.37 to .025. I had forgotten to do that prior to dyno day. So much for my planning.



It's running and driving well on the 175rwhp tune with plenty of power. It's a blast to drive. Had another issue crop up after 600 miles of driving since putting the turbo on. Doing a Sunday drive when I hear some debris get kicked up by my wheels and clatter along the underside of the chassis. No biggie. Happens again a few miles later. Wtf? And again! Nurse it home. Guibo. Must have misaligned the trans/drive shaft, shredded the guibo, and chunks of it or the bolts are flying off. Get it home and up on ramps. Guibo looks brand new! Must have been debris after all.

Drive it to the office. Meet girlfriend after work. More clattering debris episodes. Damn, these tyres are sticky! Oh, my exhaust sounds a bit funny all of a sudden? Nurse it back to the girlfriends garage. No need for ramps this time. Of the five studs and nuts holding the exhaust onto the turbine, only two studs and one nut are left. And the only nut left is the one that is held captive by the exhaust output adapter that has low clearance and basically holds the nut in place. So, there was debris on the road, and I left it there - my studs and nuts.



High temp loctite and we're up and running again. I need to book a follow up dyno session to get the magic 200 number.

Next issue was the waste gate actuator being too close to the fender. The 8mm of clearance wasn't enough and sufficient contact was made occasionally when running to remove some paint. I needed a thinner T25/T3 flange adapter which would bring the turbo closer to the manifold and increase the gap. Ordered another adapter (my third flange adapter!) from Hong Kong on eBay which was a single piece item (last adapter was two piece) which came with both gaskets in copper. Quality and fit was good but one of the copper gaskets blew out (!?) on the first run.





After some sage advice from my uncle back in New Zealand who has a bit of auto racing history and a lot of auto mechanic history, I reverted to regular gaskets, switched to copper coated exhaust nuts (brass wouldn't hold) and it has been rock solid ever since. I have done 1,200 with the turbo and 500 on the current config which seems to be holding together very well.

She even gets me to work rapidly...



...and the grandkids like to play in the "funny little car":





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Any updates - have you made it back to the dyno after sorting out the boost leaks etc?

It's pretty interesting that the peak power has moved up in the rpm range compared to NA (and that despite boost declining). Suggests you are nowhere near the turbo causing back pressure problems.

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Very impressive and incredibly thorough write-up! Nicely done and I look forward to following your build as it evolves!



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