I've got a 1990 TT which has done 70,000km, its always had major hesitation etc etc. I pulled the engine to find out the auto shop that replaced the cambelt etc about a year before I bought it must of been run by 12 year olds. Timing was out, tensioner bolts were finger tight and the crank pulley was chipped enough to give it a nice bottom end knock. I could go on but I'll get to the point, while I've got the TT out I'm going to go for a full performance build which is going to take a while of saving. Now, I have two N/A engines their both good runners with low km's and one had just been rebuilt too, I'm looking to +TT one til I get the real TT build finished. I'm just curious weather running n/a heads as well would be possible? I know it's not ideal their quite different + the weaker pins in the bottom end etc but only running low boost i should be okay for a while right? Also can the stock TT ecu run the higher compression ratio without having to tune it? No hate please I know it's gonna be dodgy, just want to be able to drive her til I can afford the tt parts, blowing the n/a up isnt a worry. Getting very depressing seeing her sitting there, any help would be much appreciated
Should be fine on low boost, maybe stick to single figures. Nistune your ECU so you can tune as necessary.
Not that dodgy. Eric (RIP) built a NA+TT for his wife. He said it was super responsive and a good bit of fun. Need to have your tune sorted though!
If I remember rightly Eric(RIP) didn't have intercooling but limited boost to 7psi, as Chrispy says, virtually no lag.
With a tune, intercooler and oil cooler a full stock NA takes 10psi fine. Only real worry with NA heads is some of the first production year had shitty exhaust valves which would burn out quicker with boost, if they haven't already.
Awesome thanks allot! I dropped the n/a + TT in the other day, just waiting on a few gaskets and hopefully be on the road again. I manual swapped it as well so there should be a very noticeable difference. Ill be running stock boost with intercooler and oil cooler, don't wanna give her any excuse to blow up on me lol. Just one more question sorry, will it be drive able without a tune? I live far out of town just wandering if I'll need to trailer her to the tuning shop or not. Cheers guys really appreciate it
If you drive it constantly under 3000rpm it 'should' be OK, boost doesn't come on until 4000+. Though the TT ecu won't know about the higher compression ratio, so I don't know how this will affect it running at 2500-3000rpm for an extended period on the open road into town. Would be safer to trailer it.
It will drive fine on a stock ecu and stock injectors, just don't be tempted to give it a squirt while doing so.
Awesome cheers guys, might trailer it to be safe. Martin im using TT injectors, oil pump and ecu + everything else besides internals. Strangely the block has TT oil squirters as well which is a bonus, i'll let you guys know the results hopefully be finished in a day or two. I'll post a few pics of the process too in case anyone wants a look, thanks again guys appreciate it
Sorry I was under the impression N/A's had no piston squirters, so yes they'll be n/a squirters. Onto the finishing touches now, should be starting her up tomorrow
Sorry for the double post, just one last question please. I was thinking of bypassing the boost solenoids to run in safety boost 7psi max, just curious if being in safety boost affects anything else or only psi? Do I just cap the turbo vac nipples and run a hose straight from the waste gate to the front intake tubes? Any help much appreciated
You can just unplug the electrical connectors from the boost solenoids. If you've got the engine out then run a single hose between the two points the boost solenoid connects to. The ECU won't have a clue that you've done either, so won't affect anything else.
Awesome thank you, engines in the car so that would be easier. ill be starting her up after work so fingers crossed
Hey guys sorry for the late reply. Everything went according to plan, on pre tune startup she idled a bit high but other than that sounded good. I managed to drive it to the tune shop with no worries, just ran low rpm being careful not to build boost. The place I took it too wasn't very flash but they done what they could, lowering the idle and a few other things. Post tune it runs awesome virtually no lag whatsoever and it has roughly triple the power my dodgy TT had lol. I haven't taken it past 6500rpm yet but I think she'll handle it sweet considering I'm only running 7psi, all in all I would definitely recommend +TT to anyone in a similar situation. Although sourcing a genuine TT is always a better option I believe this can be done safely and the power increase is huge. If I was to do this again though I would change to TT rods and thicker Cometic MLS head gaskets for peace of mind and slightly lower compression. By the way what Gas I should be running Im using 95 octane at the moment but a few people have told me to go 91 for safer ignitions is this true? I've also documented the entire swap process, would anyone be interested in a tutorial thread with pics? Was a relatively straight forward swap but it definately would of been easier having something to go off. Thanks again for all the help guys really appreciate it
